Thumbs up on that decision. Thumbs up also on finding 50 more peak HP and 1200 RPM greater HP peak. Finding the missing torque will yield a ton of power across the curve.
Dyno possibly reading rpm wrong. Like it thinks it’s looking at a 6 cylinder. Back in the old days you remember the sun tack that had the switch you could flip for 4,6,8? 4 would double the rpm. I know it’s video but it doesn’t sound like 8k ish rpm.🤷♂️
Dude, I have never read anyone calling you an idiot!! Don't be so hard on yourself!! I for one, really appreciate what you do and give to the community!
Ya man shit happens..could of been worse. Like what happened to me, 2017 in finals with my sml blk 406, and I was at 3/4 track and my fluiddamper snapped the snout , blew my shit up, list the race and I never did find that cranksnout or fluid damper…
Richard Holdner recently had a similar issue with a SBF. He lost 50 ft./lbs. from previous pulls and couldn't figure out why. Turns out the collectors on the headers were way shorter and causing it! Put on the headers with longer collectors they used before and BAM! torque returned to where it was.
I agree with you, this I what I typed in my own comment further down:::::I think it would be good ask someone that is very familiar with the computer program (pipe-max) to simulate what the “ideal” header design would be, then you could at least see, “how close” the headers you used to test are to the “optimized” design......As others have said playing with header extensions would be a good next step on a different dyno (and likely the cheapest experiment), but I’d personally want to go there with multiple sets of headers, because of how much of a difference you saw on the dyno already with just a header swap......The next “cheapest” would be to get a set of (sprint-headers) from Schoenfeld in the raw, with slip on collectors....that way you could cut the primary’s to the length you want, get the merge collector dimensions you want (to match pipe-max calcs), so your going to the dyno with theoretically the best chance of obtaining the max gains from the exhaust side as possible.....I understand they wouldn’t fit his truck, but at least the investment could be re-used in testing future engines, and would tell you if it’s worth him buying a new set of headers / not....LASTLY; I’m by no means a camshaft expert but, I know the trends you observe during header tuning can be a “tell” to an engine having unoptimized camshaft events, and what direction to go with the next cam.
@@ericschumacher5189 If you been around the LS and Fox body debates for the last 10-20 years it seems in a 347-408 situation that 1 7/8" headers win out. 2" are too big. 1 3/4" provide off idle assistance, but you lose a little at the top over 1 7/8" and 1 3/4" stepped into 1 7/8" are a great compromise of the two. 2 1/4" is way too big, 1 5/8" is too small for something over 500HP.
What these guys said. You are super sharp and I greatly apreciate your knowledge, Genius.. But from this idiot me Id bet the huge headers are atleast contributing to the tq loss. I've had similar experiences with big, short primaries and short collectors,, killed tq.
Hey eric, in my engine world - more flow and and area rarely makes more power - OR torque. We work on really advanced 4 valve heads that produce hug power per CI or CC, and really good torque as well. The rev really high, a 4 inch bore engine will limiter at 11500 or 12000 for lower hour engines ( in our world - a 11500 engine will last 100 hours of extreme hard run time). It's frustrating but finding what the engines want is not achievable fo rme on the flow bench. We just dyno our ideas and see now - coupled with baseline flow testing to confirm our measured areas match up to flow rates. Our 80mm bore engines (about half displacement) rev to 15000, last 20 hours, and make even more power per cc but not the torque per cc. I think ultimately heads get to a point were at extremely high delta p's seen in running condition they just want to be taller/straighter rather than more area. Most often we fill floors up - but oddly enough some heads need epoxy in the roof too. Point is - after a certain point, it's not about flow we can measure but about flow quality. WE also see that bigger ports like smaller cams, smaller ports bigger (relatively to one another). Contrary to what the magazine car world says. And we run extremely "advanced" inlet cam timing considering the rpm and cam sizes. Almost always as much advance as we can get in the cam until piston to valve. I think a really informative test moving forward for you will be getting to try diff heads on the dyno back to back to back...with various MCSA and such.
Torque is REAL, can be measured on a scale (Pounds). Horsepower is mathematical. If a engine makes 1. 400 lbs/pounds at 2500 rpm = 190 2. 400 lbs/pounds at 5000 rpm = 380 If the heads can /cam keep the supply of airflow into the cylinders the same, at twice the rpm = twice the horsepower.
@@billywilliams6853 most people don’t understand horsepower….. The fact is horsepower is real, it ultimately is the more important number for racing, and it ALSO can be measured. Inertia dyno’s measure POWER. Torque is calculated from there.
@@garykarenmcgruther6386 the low torque of 501 tq on 406 cubes also jumped out at me. A good built 347 to 355 ci engine will make 500 to even 525 tq in a great build. A good 400 to 414 ci will make over 600 tq. If it made under 550 tq I'd start looking for inefficiencies or mismatch parts.
I would swap the camshaft keep the duration the same but have it ground with the same 103 lobe separation that the old camshaft was ground on I'm pretty sure that would help bring the torque back and pull the power down to a lower RPM for that duration. Between those great heads and the 108 lobe separation that it has now it's probably what's making the engine Carry further up the RPM range
Many years back I built a 383ci engine.11.1 compression. I had built 2” headers with 4” collectors with 5’ extensions. On the Dino torque was way down. I slid in 4” x 4’ spiral baffles from a radiant tube heater. Picked up 50ftlb instantly. My hunch is a combination of the Dino possibly being off and header collector length are playing a big part in your results.
From what I've experienced, with almost 50 years in, I think you're frustrated to the point of having scattered thoughts, I call it. Back off of it for a day or two, put it out of your mind, then return with a fresh mind. You're already chasing what I would naturally go to, which is the cam. Sometimes, engines throw you a pretty big curve, relative to what you know works. It usually only takes a slight difference in a single thing, to wake that particular engine up. You have infinite more resources at your disposal than I have ever had, and I know you will find it. Thanks for sharing this, this is where everyone learns. Keep it up, it will work itself out. I hope you will continue to share your experiences with us.
Eric, try those heads on a larger displacement sbc. You are getting big block, big cubic inch flow numbers from your mods which is what you would want for a full race engine. That 406 would pull like a freight train on the top end!
Hi Eric. In my experience the bigger the problem, the more simple the answer. Because you have overlooked it so many times. That said, you said you checked the cam timing, but you only mentioned the intake lobe. I personally always check the exhaust lobe as well. I have had custom cams supplied to me where they have not ground what I asked for, because they thought they knew better. I've had a few arguments with cam grinders, they even supplied a cam card that said I was supplied what I asked for. I had a motor back firing at 6000rpm through the carby, eventually I rectified it by changing the headers, it was a wave tuning issue/reversion issue. That said, I would suggest carefully looking at the cam, intake and exhaust, adding some collector length. The fact that the power keeps climbing might suggest that the exhaust side is not working as designed. We are of course assuming that the dyno numbers are actually in the ball park. With all of the sensor issues there would appear to be some justification for doubt. Good luck with this challenge, but please go back to basics first. Regards Greg.
Port volosity issues ? Maybe the exhaust port is to big so it's lost the scavenging effect it would explain the tq loss and way the peak power has moved so high in the rpm range because the scavenging doesn't start working again until the engine is reving like a jet the sudden torque jump could be the point the scavenging effect is starting to work
Ask yourself, "what's really changed" compared to your other builds? For starters I would try a different dyno, 2nd I would suspect a camshaft issue if the dyno is eliminated.
Most of it is the cam I think. Those comp K lobes are very aggressive and great until they send the valvetrain crazy and lose control. Plus now your also hurting torque by closing the intake valve later.
I wonder how much a difference a dual plane intake would make. My guess is the air speed has peaked, but because of the intake design it can still keep ingesting more air at high rpms. Or maybe lower the rocker arm ratio so there is less lift. Might help low lift air speed, but these are just ideas. Can't say I know any more than Eric about what is happening. Still a good engine though.
Lowered air speed would decrease cyl pressure which would reduce torque. Higher RPM increases air speed then in comes the power. The 3 most important things for power production is, air speed, air speed and air speed.
That's some impressive HP for that duration cam. I'm thinking the intake is on the big side. Maybe tighter lobe separation. But I am wondering about the dyno calculation of torque .of course I'm guessing
Sometimes we plan on a certain result and the engine does want it wants! I understand you missed the target rpm you wanted. It'll be if he try a dyno once it's installed in the truck and see how it does then. Thank you for your time and all your information you freely share! Ive learned way more being able to better understand head flow, velocities and coefficients/ effects on power. You'll get it figured out thats one thing I know from watching you! Take you time and relax, you got this!
And I enjoy your videos and the tips. I have a Pro street 73 Plymouth Duster that went low 9 seconds in the quarter mile with just a 100 shot of nos. Andy helped me build a 421 cubic inch small block from a 340 block and a set of brodex B1 ba heads.
I ruined a good intake messing around on the floor of it . Lessons hard school . Getting recipes to be perfact & duplicate is like heart surgery's. Cool & Clever vidio 🥂🏁🥂🏁
Eric, Nothing to be ashamed about. I would advance cam timing 4 to 6 degrees. Intake port volume may be too large & could require some epoxy filling. This is why you dyno. Great first attempt. You'll get it. Terry
As with all of your videos, I appreciate all of your efforts to share your knowledge and experiences. I can see how this is a head scratcher. My first thought was cam timing and lobe separation. Further in through watching this, I more and more question the dyno accuracy. I would try another dyno, and if that done fix it, I would try a different intake and then change the cam if the intake don't make much difference. Tighten lobe separation. I'm curious and look forward to a follow up as to what happens with this engine and issue you ran into. I've never seen a cam that size make power that high.
I don’t think it’s one thing! I would try the old cam just to eliminate some variables. I wouldn’t be suprised If the torque is better (but still down from before). It would be really interesting to see where it noses over with that one (If you see what I mean). Still have huge respect for you! Keep up the good work 👍. Johan Lindstrom/LRE Sweden 🇸🇪
I feel your pain, have had similar experience eventually traced to turbulence entering the chamber smooth that out and the power came back, you've probably looked at that one already just thought id pass on my experience. an old guy who used to build Formula one engines said to me never doubt the dyno that is a big mistake. thanks for all the videos.
Another great video Eric. I got faith in you, you'll figure it out. Without a doubt the dyno is off, as well as the camshaft. I don't know your full head flow and valve sizes, or your rocker ratio. I'm not sure how you figured .750 of intake and .690 of exhaust. Based off what you showed I calculated this: The cam has a lift of .590 (intake) and .656 (exhaust) with a 1.6 rocker. 648HP 7100rpm and 539TQ at 5500rpm. I guessed the rocker arm ratio. Just for fun, I'd do a leak down test to see if something could be going on with the rings.
We had similar issue with my TFS R-Series (from TEA 356cfm@700 lift intake 282@700 exhaust) headed 13:1 430W on E-85🌽: 1st cam had to much split duration; it was LSM 55MM 282/296 @.50 768/768 net lift. #Lunati signature series crank, Oliver speedway series rods, diamond pistons. We thought the motor would flirt with 800 horse and it only made 705/559 tq. My engine builder said "F it" and we spec'd another cam. Ended going with a comp 271/281@ .753/753 net lift. The smaller cam made 716/592 hp/tq and made a lot more lower end tq too. The 1st cam from LSM was a custom ground that was heavily nitrous spec'd but because duratiin split was 14* degrees it was bleeding off cylinder press and losing power NA. Sinve the motor will spend most of its life NA - the 2nd cam split duration was only 10* degrees. We still think a motor like that shoulda made mid 700s power and lower 600s tq, but the only thing we can think if is it has a heavy ring pack, so there's rotational friction holding it back. Checkout my channel for both dyno videos: 430W dyno pt 1 & 2. 📷📸📽🏁🎬🔥
Did you ever get new numbers on the 430w? From your results I'd look at bring exhaust duration down even more or run 1.72 rockeer intake and 1.60 exhaust. What was the intake and carb on it? Its wild that you got nearly 50 ftlb but not much more power.
It would be interesting to see the dynamic compression between the two camshafts or cranking compression. The wider lobe separation is going to hamper the torque and raise the rpm range. What was the intake centerline. I’d think it would need to be between 104/105 to peak somewhere near the rpm range you’re looking for. Also was the race fuel oxygenated? If not that will also hurt it some. That’s a lot of torque to be down.
I think you are dead on John. I noticed in the cam video that the .050 number to the seat was forever. I'd bet the difference between .050 and when the valve actually hits the seat between those two cams is a ton. I know Eric said he PAYS NO ATTENTION to advertised numbers but the cam doctor info when the valve actually hits the seat matters!
Excellent opportunity to learn something. You're gonna come out on the other side of this more knowledgeable than before, and thanks to the miracle of youtube we all can benefit from this experience.
Eric, is this just an example of changing too many things at once? From the engine master build you are comparing numbers with, you have a different cam, head port work, different intake, and a larger (950 vs 750?) carb. Interactions of 4 changes??? For what its worth. And at some point, adding another 50 HP is going to cost you torque right? (1.75 hp per cube). Keep going!
Put the same engine masters intake and carb on a dyno pull and split the mental masterbation in half. Did the cam and port work kill the low end torgue, or did the the intake and carb. I am not an expert, hard stop. But watching all the combos with Richard Holder, I bet a twelve pack the intake and 950 shifted the torque peak up. Sacrificig low end torque for HP. Yada yada..... the cliches. Divide and concore. You are a determined man that will not sleep until resolved in your mind. The smaller tube headers are my hint. I would love to see the same combo you dynoed with the same induction (engine masters) you have built you estimates on. AND, let me know your beer of choice. A bet I'm willing to loose out of couiosity. Divide 4 changes in half. I enjoy your videos, and respect your resolve. .
I second what others said about collector extensions. But if you really want to have an accurate test, you've gotta run the headers you're gonna run in the chassis. What engine masters found with collector extension is you basically have resonant tubes behind the headers up until you hit a muffler. For open headers drag racing you'd want a particular length collector extension for optimum torque.
I would re-dyno on a different dyno, all the things you said weren't working properly sends up red flags to me. also, I'm wondering about the CC soft lobes, I think those do soften torque and promote that high rpm peak. another cam with the same numbers (ILC and LCA) with a more aggressive ramp may help....good luck, keep the great ifo coming.
Hey Eric, great information on the video! I seriously doubt it was anything you did. That engine should have hit it out of the park. I think something could have been wrong with the dyno. You said the air hat sensor was questionable. Did he run a known motor on it recently with no known issues? My suggestion would be after Cecil gets it installed to run it on a chassis dyno. If your torque and hp are down similarly across the board, I would suspect some clearance or something in the bottom end is too tight. If you end up making 500 ft lbs or more on the chassis dyno, you found your problem. Keep up the great work, you're an awesome dude!!!
I remember a few years back a local shop that was doing all my machine work was upgrading their customers 418sbc. I can't remember if the engine had a Dart 230 or Brodix 230 but one of the "upgrades" was going to be the brand new AFR245. They fly cut the pistons for some additional P to V so probably lost a little compression (comb chamber volume before/aft?) and changed the rockers taking the cam from around .680" lift to around .725". In doing that they inadvertently added more duration therefore bleeding off even more compression.. On their dyno the engine previously made just over 650hp with the old combo and around 530tq. They spanked that poor engine silly for days and could only get 660hp out of it and lost a whack load of torque. I even lent them a set of 1-7/8x2x3-1/2" sprint car headers with 2 feet of collectors on them. In the end they swapped the AFR245 for an AFR227 and the engine made 685hp and 565tq. Good luck. I hope you get it sorted out. Love the content!
1 7/8 headers seem really big to me. Doing some quick calcs, at 8k rpm your still only getting about 350ft/s. Even with the smallish camshaft i am really surprised it made power way out there at 8k rpm. In the chassis an H pipe would make a bunch in the middle, without the extensions on the headers it doesnt surprise me that it was kind of gutless down low but 100ftlbs seems like a lot to take off the bottom. That 4 degrees of LSA is going to do something as well. It is maybe a confluence of these factors. Without a functioning air hat that makes diagnosis tough.
350-400 ci engines from 6-8000 RPM seem to like 1 7/8" headers. These results come from the many LS dynos. 1 3/4" make a little more torque down low but not much, and 2" are just too big. Like Eric said collector length can make a huge difference, and header design. But check over there, they have tons of data, and 1 7/8" is the winner.
@@the318pop True. I was saying what counts for us is the inside diameter. However, when we model after known combos and they state a known header of a known OD, that data is still useful. But for the engine models and simulations, the ID is what determines the exhaust capability of the engine.
It’s alright Eric, let’s see if we can diagnose this, so the first thing that caught my attention was the headers way to big for the displacement. Maybe 1 3/4 going to 1 7/8 would’ve been about right. Not sure if this cam was bought for this stage of the engine but 108* LSA, I’d probably go with 105-106. I’d almost question the performance of the dyno maybe something is wrong with it, besides some of the sensors. Are the rings broken in? The lash set correctly? A lot of times when things are changed from baseline, you got look back at what has changed and what’s the same. You’ll figure it out Eric your a smart dude!
It's mostly the intake and headers, but you stated everything in this video. You have your answers. It's that the overall combination now hits just right to make it scream. It was being held back before to maximize TQ, and now it's not.
When you degreed the cam to get true valve timing you have to load it with the valve pressure I have seen up to 4 degrees with single point tension belt drives and 1.5 on the jesel according to spring pressure
Double check where the cam is installed, I bet the cam is installed late, 1 tooth off =14.4° maybe the adjuster slipped. After watching your video, I would think that the dyno was the problem, those cam numbers sound a little short to turn those kind of RPMs not to mention it's on a 108 lobe Center
Eric. I've been modifying high performance multi valve heads for race and rally for forty years. Although you are being hard on yourself, you have actually discovered the sweet spot. For an engine curve to not "turn over" and continue revving with more power like that means the system itself is perfect. It's just the numbers don't suit you. Somewhere along the line, a part of the inlet tract (manifold runners?) are too large (or flowing more no matter what size- could be the shapes?) and the whole thing needs choking down up to the throat. As an upside, I bet that engine will sound glorious in a circuit race car.
Just a suggestion, do a leak down test. Check the percentages. Your idea of advancing the cam. Header extensions. Change manifold. Great content. Nice horse power, says heads Are working. The camshaft is conservative. Thank you, EM.
11.5:1 compression have you thought about header extensions? 501tq is great numbers depending on the application the engine is used for plus depending on what chassis is going in. That engine in my 66 Chevy II Nova would run great times in the 1/4 mile.
@@dennisrobinson8008 but remember cam profile, duration, lift and LSA all can cause low torque production and high horsepower production. I would suggest looking at the cam first and see if installing a different cam would change the outcome of the engine powerband/torqueband
@@dennisrobinson8008 I'm a Honda enthusiast, so my main goal for my racecar is to mid range and topend power. My f20b engine makes 14.5:1 compression, 13mm lift with a 315⁰ duration. My rev limit is 10,500rpm and on ignite red I make close to 400whp all motor, and on M1 race gas I make close 450whp. If I want more of a mid range powerband I would change the duration to lower my rpm range and increase my torque production thus increasing my low to mid range usage. But those cams I use it when I'm track/time attack racing my first cams that I talked about that allows me to rev to 10,500rpm are my drag racing cams
curious about the resolution was... I had done a 468 (14.5:1 NA on methanol) and was running different cams through the thing on a Gopower dyno.. One change was for an Erson cam they sent us to try. (was an incrementally larger cam on all numbers) . The first cold fire up and warmup tha thing sounded like a killer.. Engine was probably 25% snappier off load.. So first pull, the torque curve was off by over 100ftlbs.... so back to the dial indicator and degree wheel.. was right were it belonged, so... bumped it up 2º and it did not improve.. Really did not work on that cam any further.. As this was running in a drag boat, there was no room for the impaired torque curve.. I am used to trading torque for HP and vica versa but this cam was only a tiny bit larger but made a giant difference.. Probably should have worked on it more but like you, I was pretty unhappy on that session...
Thinking about my previous comment, I think i would install the original cam and dyno again, i think this would also showcase your porting skills and make an awesome comparison.
What ended up being the answer? I forgot but others mentioned Richard Holdener situation where 50 ft lb was "missing" and it was due to having no extensions after the collector.
Intake plenum volume has a treshold, where it stops pulling new air through the carb, and only feeding the cylinders with the mist that lingers in the plenum. You should've taken it to the 9000, just to see how it reacts. Second thing is the lobe separation/exhaust valve timing. When you are running high octane fuel, it burns slowly and if the exhaust valve opens before the fuel has done it's job, the power output goes down. This is backed by the smaller header, so when there's more back pressure in the exhaust, it makes more power, keeping the combustion inside the chamber. One quick fix is bigger lash on the exhaust valve, another is faster burning fuel. but both of these won't help on the plenum volume. If you have a spacer on the intake, take it off and try again.
Eric, 1st I would test another dyno. If it duplicates or is close to the same results then I’d look at the cam lobes. Is the cam lobe design ( low shock) bleeding off to much cylinder pressure down low hurting the torque but carrying out up top to make good power beyond 7500rpm? Just a thought. 🤷🏻♂️
I would verify those numbers elsewhere if possible. It could have been a loading issue. If it does turn out the same, my personal opinion would be the air speed. Im no porter, but have some experience with it. If by changing the short side it dropped a ton of air speed, it may have hurt it enough to need the higher rpm to meet same demand.
My buddy brought his blown big block Chevy to the dyno, the first run it made 400 horsepower. After almost puking they went over the motor, found nothing wrong mechanically, pulled the plugs and they all looked weird, so they changed the plugs and picked up 300 horsepower with no other changes, sometimes it’s the simple things that you overlook that make the most difference. After that the dominator carb wouldn’t work and after a few pulls they called it quits
I looked some more at your sheet , the dyno correction is drifting or cal is off, look at your torque , it peaks then remain flat for over 1500 rpm , I think the dyno has a strain gauge issue. He needs to rehang his cal weights.
I'd look into the rod ratio at high rpm. Unless it was a raised deck block, that pass poor rod ratio of a 400 can kill torque while making great power with a similar stroke in a taller block.
Hi Eric, brave video sir. What did you do to the ex port? Try a manifold with way less volume, and l dont get the small cam durations. Colin Lloyd, Headsense Engines Heads,, Aust
I would be mad about going to an engine dyno and their equipment being messed up and not working correctly. I my head I am thinking, well if the basic peripherals aren't working, how can I trust what the dyno is telling me? I understand each dyno is different, and for comparison sake using the same one is the best idea, but in this case I'd be tempted to find another dyno.
Man I was just typing out a comment that the cam should be checked and then you go into the details of having it checked. I've got a set of your dragon slayers from 2016 going on my 427 with a Jones 254/256 solid roller an planning on dynoing it before installing in the car.
I build a little 355 engine I called Summit Racing and they told me to put a 465 lift cam in it with 224 intake 224 exhaust I did what they told me to do Andy engine would fly it was fast as hell I went with 10.8 compression ratio that was enough for the street your truck would jump sideways the people at Summit Racing know what they're talkin about but I like the video man keep up the good work
It seems you`ve built an open wheeled circle track motor, more compression, more cam shaft and crank it to 8500+ and that pump would scream. I hosed myself like this about 25yrs ago with a superlate model asphalt motor. I replaced an 034 bowtie casting 207cc intake runner with a 220 RHS head, with a solid roller instead of a solid flat tappet that was in the 034 head. Lost maybe 60ft/lbs of torque and only gained 18hp, it was sleepy under 5500 and reached max hp at 7700rpm. Respectfully I believe the loss of torque was the cylinders weren`t being filled, so I had the intake valves increased to 2.050 on the bowtie heads (new rule change) and bowls blended, kept the solid roller and that was what we needed. Got back 90lbs torque (+30 net) and about 60 hp (48Hp net). For what it`s worth my friend, good luck and don`t beat yourself up too much.
I'm definetly no expert but on my bb 67 Camaro i had 30 years ago and my pressent day 512 ci 73 challenger my lift on the exhaust valve is higher than the intake. I picked this cam based on a formula I found on the youtube channel Myvintageiron. his formula was pretty in depth. You may want to check it out.
I would get that cam measured out, nevermind lol. I think 8 degrees and that LSA change was enough to do it. The valve opening at TDC combined with a different port shape could be really hurting low speed flow
Have you heard of the IOP program? Might be worth checking out? We know the AFR227 you ported was good. If we say 233 ccm / 5.1 inch length, we get average CSA of 2.79 inch square. A 2.08 valve is 3.4 inch square and 2.79 / 3.4 = 82 % as Area and 90.6% as diameter. I belive this is high enough and this latest engine has way more than this. That may kill torque due to low port energy. Also, I must remind all that Darin Morgen has warned us all about touching the "hyper critical SSR" on some heads. ua-cam.com/video/qhsTQn0uUOQ/v-deo.html ua-cam.com/video/lcxp9ufC1DY/v-deo.html AFR @20:34 show way lean in the midrange. Looking at the torque curve, it does taper of.
A 7* later IVC (best I can figure based on the cam numbers and assuming you've got them both 4* advanced) is gonna shift power up substantially, and kill the low end. I'm headed to the redemption video now to see what you learned.
I’m guessing that the dyno is not exactly correct and the headers are hurting more than we really expect them to. But my explanation for the power loss is the intake manifold. Large intake manifold will definitely kill torque and make big rpm’s up top!!! JMO. Great video.
Having looked at this over and over, I have an ide and it is related to the timing of the cam. I am conserned with Smokey Yunicks XO or Cross over point which is very important. This is when both valves are opened the same amount around TDC. XO at TDC is "Straight up". You say you have 248 degrees in and 253 degrees exhaust on a 108. The extra early exhaust valve opening can be confusing as it covers up what overlap wise, this is like a 248/248/106.75 degrees cam. You have installed it at 107.5 degrees and ergo TDC lift confimes that the cam is way retarded with 0.98" lift on the intake valves and 1.16" lift on the exhaust valve in TDC. This usually kills torque and makes the engine rev. We always start with exhaust valve lift 66% - 75% of the lift that the intake valve have in TDC. As a very rough guide; 0.98 + 1.16 = 2.14 / 2 = 107. Then +/- 15 for 1.27 for intake and 0.92 for exhaust. 0.92 / 1.27 = 74.5%. His would be mye least advanced starting point. :) Just my 2 cents.
My last engine a cleveland 408 with unported CHI heads and manifold with 11.5 comp and 262/272@50 and 721 lift it dynoed from 4500 made 429 hp and 501 lb of torque and peak torque 546.5 at 5500 and made 655 hp @7000.This was done with a superflow 902,but my engine builder says that his dyno is rated differently to a lot of dynos,being a drag race builder he says his hp equats to the moroso calulater,your deal doesnt sound like that weeny cam
if I remember right from the other video you put a new cam with less aggressive lobe profiles to help be easier on the valvetrain. Maybe the profile change is hurting torque? Also think the dyno having some issues that day could be a factor and would probably start there with a different dyno to confirm.
I think you are on the right path with going back to the original camshaft. The compression is a bit low. Were the valve seats ground? Lowering the compression even more? Maybe an angle mill on the heads to raise compression?
I feel your frustration, I invested way too much time just getting all the blue printing aircraft quality right. Seemingly everything fought me. Though it turned out blessedly well. I'm wondering about your dyno personally. But I think 570 torque would be maximum expectation but I'm not sure. your 50 away. As for the peak hp above the 355 is just bizarre. It would keep me up at night. I'd have to spend some money to someone like kaase identify the situation. Thus might keep me up at night. There should be a way to scale reset dyno for torque and power easily.
Erik. What size the carb.I would look at changing carb.from what I saw of the early BSFC was lean.i have run 1,000 cfm pro systems carb on similar cid engines and made 600 trq around 5100.also used 1 7/8 primary 3 1/2 collector.on a quick note did you see if it had a dead cylinder,I have had that happen and it had me itching my head.the engine didn't sound like had any misfire .found it had a closed strap on the plug
I cannot remember if you degreed the camshaft, I've seen timing gears machined wrong as well as camshafts ground incorrectly. Advancing the cam timing or changing to a more narrow LSA might be the simplest trick & where I would investigate first.
I'm sorry. I do believe you had announced that. I was watching some of your older videos today & forgot what you had learned about this engine. I'm glad as it surely was bizarre results as you knew what you should expect. Gladbit worked out well. Very stout SBC and I would be very proud as I am sure you are. We'll done Eric.
Sound s to me you have a cam that makes power above your usable RPM range? Amd a merge collector with a 2.500 " cross section would work way better than a 3.5" straight?
Hey we all have our days shit happens. Did you open the ports in the heads more maybe a loss of velocity? Maybe there is to much volume in the intake I don't know I am taking shots in the dark here.
Same thing happens when people start carving on Vortec heads.. You can go the other way fast and not to mention take reliability out of them and causing weak casting points and get cracks even more...
Could it be the similar issue to the story you told about the timing and the balancer being off where you had the small block with 50°+ of timing to make any power. Seems heads are huge and cam is huge. But you the professional.lol my home built junk 406 has afr 227s and a crower solid roller 269-281 629/639 106 13-1 makes 685. With iron dart 215s 2.08 valve
Seems like those big flow numbers are doing what their supposed to do, making high rpm horsepower. I'm a little surprised that ring seal wasn't compromised at 7k + rpm. I saw a video of a chevy ro 406 Nascar engine running to 9000 rpm and made 930 hp with a 830 cfm carb. Hugh ports and more compression. Dyno readout started at 5500 rpm I think. I drag race a 406 that has run 10.7 at 4200da. I would use this engine in a heart beat. BTW, my cam is 278 deg intake duration, 718 gross lift. I run 12.5 compression using 55 cc 227 heads. I like your pragmatic approach to racing. Imo any porting should be followed with a dyno run or drag strip results.
What was the Length of the Dyno Header's Collector? What type of Carb Spacer, Open or Tapered Four Hole such as the HVH SS4150/4500-1.5A? Did you try advancing the Cam to see if it liked it? How about seeing if it liked 1.6:1 Intake and/or Exhaust Rockers?
Eric a cam I use in my 406 might help. It's a old grind from comp cams and works well. 12-906-9 . I put it in straight up , then retarded it 2 degrees and made great power.and torque.. Using out of box AFR heads , out of box Motown intake and port match to gaskets, 950cfm quick fuel, one inch HVH spacer and made upper 657Hp@ 6700 and. 538 -542 ft Torque@ 5600rpms , if I remember correctly. Shifted at 7000.
I’ve got the 12-909-9 in a 355 12:5:1 with a set of lightly ported sportsman 2 heads. Flow 285cfm on intake and the motor will run 6.50s in a 3350lb car. 750 carb
Did you check swirl on the heads as compared to the last configuration of those heads? Vizard says a lack of swirl will knock torque and power in the head right up to peak power. Maybe get rid of those LST lobes?
Strange to be sure. Degree in the cam on a companion cylinder (6 probably) and on a back cylinder. Maybe the blank slipped while being made. Also, another dyno to back up results is pretty important to not go down the wrong path before you're too invested. I would also swing that cam timing both ways, you might be surprised at some cylinder fill harmonic or something. Lastly, if all that leads no where, I would change the cam on the dyno to a known one and eliminate 1 of the variables. Look at the bright side, maybe what you learn leads to a better 60 ft on your truck by finding torque down low without hurting top end! Good luck.
Despite the numbers it must have lost cylinder pressure, unless the dyno is working different from last time. With sensors being bad and the jump at the start, it is a justified concern. Like you said it doesn't seem right. Dyno could be the reason.
This is just a thought if your intake manifold is higher than previous one and ported that has more plenum volume than the other one then would that kill the torque. But the runners are longer to so the longer runner should help on the bottom end. Another thing I was thinking to I hear a lot of racers who run 400 sbc engine either 406 or 410 like a Sprint car they run a higher compression at 13, 14, or even maybe 15:1 compression. Doesn't more compression help to especially on a bigger engine. But other than that I can't think of anything else. I don't know I don't build engines my dad does and a few people I know do. Also another thing do what's weird is should a 400 cubic inch motor should make more torque than a 350 because of the bigger bore and stroke. I don't know just a thought I figured anything helps
I'm having a hard time trusting the dyno. It clearly isn't well maintained. I understand the frustration brotha but you're certainly no idiot and I think I'd have to see similar numbers on a different dyno to be fully convinced that is a engine combination issue. That's just my opinion though, I've never personally seen less camshaft and more cubic inches move the power up in the curve up. Good luck with figuring it out, Eric, in the mean time I think Cecil will really enjoy the 477 lol!
With your big head ports and valves sound like a Nascar cup engine, you need to get the port velocity up, for the lower rpm that you want to make power at. Come tonight to Richard Holdener podcast at 7pm Pacific and ask about your engine combination
You ever think that you last build was just spot on and you just changed the harmonics and ram charging enough in the new engine where the usable rpm range is in the low spot of the tuning? It might not be the new engine is bad but the last engine was spectacular. I would keep changing intake and exhaust lengths until it is back in tune, I might even change the cam because the cam, exhaust, and intake seem to not be matched in their hmm ..... tune timing?, harmonics, or ram charging? I'm sure there are proper words for that but I'm not remembering them right now lol.
With so many issues going on with the dyno, I wouldn’t trust any of it. I’d dyno it elsewhere before changing anything
My EXACT thoughts!!!
Waste of time and money!!!
That is exactly what I would do, there's no way I would trust that dyno.
Thumbs up on that decision. Thumbs up also on finding 50 more peak HP and 1200 RPM greater HP peak. Finding the missing torque will yield a ton of power across the curve.
Dyno possibly reading rpm wrong. Like it thinks it’s looking at a 6 cylinder. Back in the old days you remember the sun tack that had the switch you could flip for 4,6,8? 4 would double the rpm. I know it’s video but it doesn’t sound like 8k ish rpm.🤷♂️
@@besgar5172 Yes, dyno somewhere else. Just do it on a dynojet.
Dude, I have never read anyone calling you an idiot!! Don't be so hard on yourself!! I for one, really appreciate what you do and give to the community!
Same here
Ya man shit happens..could of been worse. Like what happened to me, 2017 in finals with my sml blk 406, and I was at 3/4 track and my fluiddamper snapped the snout , blew my shit up, list the race and I never did find that cranksnout or fluid damper…
Richard Holdner recently had a similar issue with a SBF. He lost 50 ft./lbs. from previous pulls and couldn't figure out why. Turns out the collectors on the headers were way shorter and causing it! Put on the headers with longer collectors they used before and BAM! torque returned to where it was.
Yep, I remember this, Agreed!! Check collector length!
I agree with you, this I what I typed in my own comment further down:::::I think it would be good ask someone that is very familiar with the computer program (pipe-max) to simulate what the “ideal” header design would be, then you could at least see, “how close” the headers you used to test are to the “optimized” design......As others have said playing with header extensions would be a good next step on a different dyno (and likely the cheapest experiment), but I’d personally want to go there with multiple sets of headers, because of how much of a difference you saw on the dyno already with just a header swap......The next “cheapest” would be to get a set of (sprint-headers) from Schoenfeld in the raw, with slip on collectors....that way you could cut the primary’s to the length you want, get the merge collector dimensions you want (to match pipe-max calcs), so your going to the dyno with theoretically the best chance of obtaining the max gains from the exhaust side as possible.....I understand they wouldn’t fit his truck, but at least the investment could be re-used in testing future engines, and would tell you if it’s worth him buying a new set of headers / not....LASTLY; I’m by no means a camshaft expert but, I know the trends you observe during header tuning can be a “tell” to an engine having unoptimized camshaft events, and what direction to go with the next cam.
@@ericschumacher5189 If you been around the LS and Fox body debates for the last 10-20 years it seems in a 347-408 situation that 1 7/8" headers win out. 2" are too big. 1 3/4" provide off idle assistance, but you lose a little at the top over 1 7/8" and 1 3/4" stepped into 1 7/8" are a great compromise of the two. 2 1/4" is way too big, 1 5/8" is too small for something over 500HP.
What these guys said. You are super sharp and I greatly apreciate your knowledge, Genius..
But from this idiot me Id bet the huge headers are atleast contributing to the tq loss. I've had similar experiences with big, short primaries and short collectors,, killed tq.
Amazing how much a small design change can help or hurt power so much.
Hey eric, in my engine world - more flow and and area rarely makes more power - OR torque. We work on really advanced 4 valve heads that produce hug power per CI or CC, and really good torque as well. The rev really high, a 4 inch bore engine will limiter at 11500 or 12000 for lower hour engines ( in our world - a 11500 engine will last 100 hours of extreme hard run time). It's frustrating but finding what the engines want is not achievable fo rme on the flow bench. We just dyno our ideas and see now - coupled with baseline flow testing to confirm our measured areas match up to flow rates. Our 80mm bore engines (about half displacement) rev to 15000, last 20 hours, and make even more power per cc but not the torque per cc. I think ultimately heads get to a point were at extremely high delta p's seen in running condition they just want to be taller/straighter rather than more area. Most often we fill floors up - but oddly enough some heads need epoxy in the roof too. Point is - after a certain point, it's not about flow we can measure but about flow quality. WE also see that bigger ports like smaller cams, smaller ports bigger (relatively to one another). Contrary to what the magazine car world says. And we run extremely "advanced" inlet cam timing considering the rpm and cam sizes. Almost always as much advance as we can get in the cam until piston to valve. I think a really informative test moving forward for you will be getting to try diff heads on the dyno back to back to back...with various MCSA and such.
I agree, the intake port is to large.
Or
Engine to small.
Torque is REAL, can be measured on a scale (Pounds).
Horsepower is mathematical.
If a engine makes
1. 400 lbs/pounds at 2500 rpm = 190
2. 400 lbs/pounds at 5000 rpm = 380
If the heads can /cam keep the supply of airflow into the cylinders the same, at twice the rpm = twice the horsepower.
@@billywilliams6853 most people don’t understand horsepower….. The fact is horsepower is real, it ultimately is the more important number for racing, and it ALSO can be measured. Inertia dyno’s measure POWER. Torque is calculated from there.
Great data. Thanks for sharing.
@@garykarenmcgruther6386 the low torque of 501 tq on 406 cubes also jumped out at me. A good built 347 to 355 ci engine will make 500 to even 525 tq in a great build. A good 400 to 414 ci will make over 600 tq. If it made under 550 tq I'd start looking for inefficiencies or mismatch parts.
Haven't even watched the whole video and already appreciate you and your work
I would swap the camshaft keep the duration the same but have it ground with the same 103 lobe separation that the old camshaft was ground on I'm pretty sure that would help bring the torque back and pull the power down to a lower RPM for that duration. Between those great heads and the 108 lobe separation that it has now it's probably what's making the engine Carry further up the RPM range
Many years back I built a 383ci engine.11.1 compression. I had built 2” headers with 4” collectors with 5’ extensions. On the Dino torque was way down. I slid in 4” x 4’ spiral baffles from a radiant tube heater. Picked up 50ftlb instantly. My hunch is a combination of the Dino possibly being off and header collector length are playing a big part in your results.
Would add in the exhaust mods which will push the RPM higher easier
From what I've experienced, with almost 50 years in, I think you're frustrated to the point of having scattered thoughts, I call it. Back off of it for a day or two, put it out of your mind, then return with a fresh mind. You're already chasing what I would naturally go to, which is the cam. Sometimes, engines throw you a pretty big curve, relative to what you know works. It usually only takes a slight difference in a single thing, to wake that particular engine up. You have infinite more resources at your disposal than I have ever had, and I know you will find it. Thanks for sharing this, this is where everyone learns. Keep it up, it will work itself out. I hope you will continue to share your experiences with us.
That seems like the Cam is much bigger than a 248 @ .050 on a 108 for it to make peak at 7900...
Eric, try those heads on a larger displacement sbc. You are getting big block, big cubic inch flow numbers from your mods which is what you would want for a full race engine. That 406 would pull like a freight train on the top end!
@@garykarenmcgruther6386 CR...
David Vizard did a piece on dynoes w/blown engines w/some pretty interesting intel!
Hi Eric. In my experience the bigger the problem, the more simple the answer. Because you have overlooked it so many times. That said, you said you checked the cam timing, but you only mentioned the intake lobe. I personally always check the exhaust lobe as well. I have had custom cams supplied to me where they have not ground what I asked for, because they thought they knew better. I've had a few arguments with cam grinders, they even supplied a cam card that said I was supplied what I asked for. I had a motor back firing at 6000rpm through the carby, eventually I rectified it by changing the headers, it was a wave tuning issue/reversion issue. That said, I would suggest carefully looking at the cam, intake and exhaust, adding some collector length. The fact that the power keeps climbing might suggest that the exhaust side is not working as designed. We are of course assuming that the dyno numbers are actually in the ball park. With all of the sensor issues there would appear to be some justification for doubt. Good luck with this challenge, but please go back to basics first. Regards Greg.
It sounds like you have 20-30 degrees more cam duration than what you thought.
Seeing those 310+ numbers of duration seat on that cam doctor. 60+ degrees from .050 to the seat? That thing is killing power!!
How much power is he expecting here? Is this not normal?
Glad you figured it out. Was thinking it may have been the wider LSA, but the fact that it was the dyno must have been a HUGE relief!
I think the lobe separation angle has reduced the tourque number as you have widened the angle and taken cylinder pressure away.
Agreed and more duration adding to the low speed problem
Port volosity issues ? Maybe the exhaust port is to big so it's lost the scavenging effect it would explain the tq loss and way the peak power has moved so high in the rpm range because the scavenging doesn't start working again until the engine is reving like a jet the sudden torque jump could be the point the scavenging effect is starting to work
Ask yourself, "what's really changed" compared to your other builds?
For starters I would try a different dyno, 2nd I would suspect a camshaft issue if the dyno is eliminated.
That’s what I was thinking…… maybe advance the cam ( I have not watched the whole video at time of leaving this comment)
With a lobe separation of 108 I don't see what surprising
He will be driving his pick up
Quarter mile @ a time.
Going to the Grocery store.
Most of it is the cam I think. Those comp K lobes are very aggressive and great until they send the valvetrain crazy and lose control. Plus now your also hurting torque by closing the intake valve later.
I wonder how much a difference a dual plane intake would make. My guess is the air speed has peaked, but because of the intake design it can still keep ingesting more air at high rpms. Or maybe lower the rocker arm ratio so there is less lift. Might help low lift air speed, but these are just ideas. Can't say I know any more than Eric about what is happening. Still a good engine though.
Lowered air speed would decrease cyl pressure which would reduce torque. Higher RPM increases air speed then in comes the power. The 3 most important things for power production is, air speed, air speed and air speed.
That's some impressive HP for that duration cam. I'm thinking the intake is on the big side. Maybe tighter lobe separation. But I am wondering about the dyno calculation of torque .of course I'm guessing
Sometimes we plan on a certain result and the engine does want it wants! I understand you missed the target rpm you wanted. It'll be if he try a dyno once it's installed in the truck and see how it does then. Thank you for your time and all your information you freely share! Ive learned way more being able to better understand head flow, velocities and coefficients/ effects on power. You'll get it figured out thats one thing I know from watching you! Take you time and relax, you got this!
And I enjoy your videos and the tips. I have a Pro street 73 Plymouth Duster that went low 9 seconds in the quarter mile with just a 100 shot of nos. Andy helped me build a 421 cubic inch small block from a 340 block and a set of brodex B1 ba heads.
I ruined a good intake messing around on the floor of it . Lessons hard school . Getting recipes to be perfact & duplicate is like heart surgery's. Cool & Clever vidio 🥂🏁🥂🏁
Eric,
Nothing to be ashamed about. I would advance cam timing 4 to 6 degrees. Intake port volume may be too large & could require some epoxy filling.
This is why you dyno. Great first attempt.
You'll get it.
Terry
As with all of your videos, I appreciate all of your efforts to share your knowledge and experiences. I can see how this is a head scratcher. My first thought was cam timing and lobe separation. Further in through watching this, I more and more question the dyno accuracy. I would try another dyno, and if that done fix it, I would try a different intake and then change the cam if the intake don't make much difference. Tighten lobe separation. I'm curious and look forward to a follow up as to what happens with this engine and issue you ran into. I've never seen a cam that size make power that high.
It ended up being the dyno. It went faster on the track.
I don’t think it’s one thing!
I would try the old cam just to eliminate some variables.
I wouldn’t be suprised If the torque is better (but still down from before).
It would be really interesting to see where it noses over with that one (If you see what I mean).
Still have huge respect for you!
Keep up the good work 👍.
Johan Lindstrom/LRE Sweden 🇸🇪
Absolutely 2nd
I feel your pain, have had similar experience eventually traced to turbulence entering the chamber smooth that out and the power came back, you've probably looked at that one already just thought id pass on my experience. an old guy who used to build Formula one engines said to me never doubt the dyno that is a big mistake. thanks for all the videos.
Another great video Eric. I got faith in you, you'll figure it out.
Without a doubt the dyno is off, as well as the camshaft. I don't know your full head flow and valve sizes, or your rocker ratio. I'm not sure how you figured .750 of intake and .690 of exhaust. Based off what you showed I calculated this:
The cam has a lift of .590 (intake) and .656 (exhaust) with a 1.6 rocker. 648HP 7100rpm and 539TQ at 5500rpm.
I guessed the rocker arm ratio. Just for fun, I'd do a leak down test to see if something could be going on with the rings.
We had similar issue with my TFS R-Series (from TEA 356cfm@700 lift intake 282@700 exhaust) headed 13:1 430W on E-85🌽: 1st cam had to much split duration; it was LSM 55MM 282/296 @.50 768/768 net lift. #Lunati signature series crank, Oliver speedway series rods, diamond pistons. We thought the motor would flirt with 800 horse and it only made 705/559 tq. My engine builder said "F it" and we spec'd another cam. Ended going with a comp 271/281@ .753/753 net lift. The smaller cam made 716/592 hp/tq and made a lot more lower end tq too. The 1st cam from LSM was a custom ground that was heavily nitrous spec'd but because duratiin split was 14* degrees it was bleeding off cylinder press and losing power NA. Sinve the motor will spend most of its life NA - the 2nd cam split duration was only 10* degrees. We still think a motor like that shoulda made mid 700s power and lower 600s tq, but the only thing we can think if is it has a heavy ring pack, so there's rotational friction holding it back. Checkout my channel for both dyno videos: 430W dyno pt 1 & 2. 📷📸📽🏁🎬🔥
Did you ever get new numbers on the 430w? From your results I'd look at bring exhaust duration down even more or run 1.72 rockeer intake and 1.60 exhaust. What was the intake and carb on it? Its wild that you got nearly 50 ftlb but not much more power.
It would be interesting to see the dynamic compression between the two camshafts or cranking compression. The wider lobe separation is going to hamper the torque and raise the rpm range. What was the intake centerline. I’d think it would need to be between 104/105 to peak somewhere near the rpm range you’re looking for. Also was the race fuel oxygenated? If not that will also hurt it some. That’s a lot of torque to be down.
I think you are dead on John. I noticed in the cam video that the .050 number to the seat was forever. I'd bet the difference between .050 and when the valve actually hits the seat between those two cams is a ton. I know Eric said he PAYS NO ATTENTION to advertised numbers but the cam doctor info when the valve actually hits the seat matters!
Especially on that 11:1 CR.
Excellent opportunity to learn something. You're gonna come out on the other side of this more knowledgeable than before, and thanks to the miracle of youtube we all can benefit from this experience.
Eric, is this just an example of changing too many things at once?
From the engine master build you are comparing numbers with, you have a different cam, head port work, different intake, and a larger (950 vs 750?) carb. Interactions of 4 changes???
For what its worth. And at some point, adding another 50 HP is going to cost you torque right? (1.75 hp per cube).
Keep going!
Put the same engine masters intake and carb on a dyno pull and split the mental masterbation in half. Did the cam and port work kill the low end torgue, or did the the intake and carb. I am not an expert, hard stop. But watching all the combos with Richard Holder, I bet a twelve pack the intake and 950 shifted the torque peak up. Sacrificig low end torque for HP. Yada yada..... the cliches.
Divide and concore. You are a determined man that will not sleep until resolved in your mind.
The smaller tube headers are my hint.
I would love to see the same combo you dynoed with the same induction (engine masters) you have built you estimates on.
AND, let me know your beer of choice. A bet I'm willing to loose out of couiosity.
Divide 4 changes in half.
I enjoy your videos, and respect your resolve.
.
I second what others said about collector extensions. But if you really want to have an accurate test, you've gotta run the headers you're gonna run in the chassis. What engine masters found with collector extension is you basically have resonant tubes behind the headers up until you hit a muffler. For open headers drag racing you'd want a particular length collector extension for optimum torque.
I would re-dyno on a different dyno, all the things you said weren't working properly sends up red flags to me. also, I'm wondering about the CC soft lobes, I think those do soften torque and promote that high rpm peak. another cam with the same numbers (ILC and LCA) with a more aggressive ramp may help....good luck, keep the great ifo coming.
Consider trying 1 3/4 × 30" long Headers. .1 7/8 stepped to 2" may be the problem.
Hey Eric, great information on the video! I seriously doubt it was anything you did. That engine should have hit it out of the park. I think something could have been wrong with the dyno. You said the air hat sensor was questionable. Did he run a known motor on it recently with no known issues? My suggestion would be after Cecil gets it installed to run it on a chassis dyno. If your torque and hp are down similarly across the board, I would suspect some clearance or something in the bottom end is too tight. If you end up making 500 ft lbs or more on the chassis dyno, you found your problem. Keep up the great work, you're an awesome dude!!!
I remember a few years back a local shop that was doing all my machine work was upgrading their customers 418sbc. I can't remember if the engine had a Dart 230 or Brodix 230 but one of the "upgrades" was going to be the brand new AFR245. They fly cut the pistons for some additional P to V so probably lost a little compression (comb chamber volume before/aft?) and changed the rockers taking the cam from around .680" lift to around .725". In doing that they inadvertently added more duration therefore bleeding off even more compression.. On their dyno the engine previously made just over 650hp with the old combo and around 530tq. They spanked that poor engine silly for days and could only get 660hp out of it and lost a whack load of torque. I even lent them a set of 1-7/8x2x3-1/2" sprint car headers with 2 feet of collectors on them. In the end they swapped the AFR245 for an AFR227 and the engine made 685hp and 565tq. Good luck. I hope you get it sorted out. Love the content!
1 7/8 headers seem really big to me. Doing some quick calcs, at 8k rpm your still only getting about 350ft/s. Even with the smallish camshaft i am really surprised it made power way out there at 8k rpm. In the chassis an H pipe would make a bunch in the middle, without the extensions on the headers it doesnt surprise me that it was kind of gutless down low but 100ftlbs seems like a lot to take off the bottom.
That 4 degrees of LSA is going to do something as well. It is maybe a confluence of these factors. Without a functioning air hat that makes diagnosis tough.
350-400 ci engines from 6-8000 RPM seem to like 1 7/8" headers. These results come from the many LS dynos. 1 3/4" make a little more torque down low but not much, and 2" are just too big. Like Eric said collector length can make a huge difference, and header design. But check over there, they have tons of data, and 1 7/8" is the winner.
It's also worth noting that that's the o.d. of the primaries, you have to allow for wall thickness when running the numbers.
@@the318pop Inside diameter.
@@dennisrobinson8008 nope, they're all measured on o.d.
@@the318pop True. I was saying what counts for us is the inside diameter. However, when we model after known combos and they state a known header of a known OD, that data is still useful. But for the engine models and simulations, the ID is what determines the exhaust capability of the engine.
It’s alright Eric, let’s see if we can diagnose this, so the first thing that caught my attention was the headers way to big for the displacement. Maybe 1 3/4 going to 1 7/8 would’ve been about right. Not sure if this cam was bought for this stage of the engine but 108* LSA, I’d probably go with 105-106. I’d almost question the performance of the dyno maybe something is wrong with it, besides some of the sensors. Are the rings broken in? The lash set correctly? A lot of times when things are changed from baseline, you got look back at what has changed and what’s the same. You’ll figure it out Eric your a smart dude!
Enjoyed the video, and good luck sorting things out. Thanks for sharing
It's mostly the intake and headers, but you stated everything in this video. You have your answers. It's that the overall combination now hits just right to make it scream. It was being held back before to maximize TQ, and now it's not.
When you degreed the cam to get true valve timing you have to load it with the valve pressure I have seen up to 4 degrees with single point tension belt drives and 1.5 on the jesel according to spring pressure
Thanks for sharing your knowledge.
Double check where the cam is installed, I bet the cam is installed late, 1 tooth off =14.4° maybe the adjuster slipped. After watching your video, I would think that the dyno was the problem, those cam numbers sound a little short to turn those kind of RPMs not to mention it's on a 108 lobe Center
I agree... And if it is a tooth off will throw away a ton of torque..
Eric. I've been modifying high performance multi valve heads for race and rally for forty years. Although you are being hard on yourself, you have actually discovered the sweet spot. For an engine curve to not "turn over" and continue revving with more power like that means the system itself is perfect. It's just the numbers don't suit you. Somewhere along the line, a part of the inlet tract (manifold runners?) are too large (or flowing more no matter what size- could be the shapes?) and the whole thing needs choking down up to the throat. As an upside, I bet that engine will sound glorious in a circuit race car.
Ive been around people engine wise since the 80s, your very very good at what you do ,make no mistake
Just a suggestion, do a leak down test.
Check the percentages.
Your idea of advancing the cam.
Header extensions.
Change manifold.
Great content.
Nice horse power, says heads Are working.
The camshaft is conservative.
Thank you, EM.
11.5:1 compression have you thought about header extensions? 501tq is great numbers depending on the application the engine is used for plus depending on what chassis is going in. That engine in my 66 Chevy II Nova would run great times in the 1/4 mile.
They are concerned because people achieve over 500tq out of a well built 350ci.
@@dennisrobinson8008 but remember cam profile, duration, lift and LSA all can cause low torque production and high horsepower production. I would suggest looking at the cam first and see if installing a different cam would change the outcome of the engine powerband/torqueband
@@eliasmelendez1271 Good observation.
@@dennisrobinson8008 I'm a Honda enthusiast, so my main goal for my racecar is to mid range and topend power. My f20b engine makes 14.5:1 compression, 13mm lift with a 315⁰ duration. My rev limit is 10,500rpm and on ignite red I make close to 400whp all motor, and on M1 race gas I make close 450whp. If I want more of a mid range powerband I would change the duration to lower my rpm range and increase my torque production thus increasing my low to mid range usage. But those cams I use it when I'm track/time attack racing my first cams that I talked about that allows me to rev to 10,500rpm are my drag racing cams
@@eliasmelendez1271 incredible numbers
curious about the resolution was... I had done a 468 (14.5:1 NA on methanol) and was running different cams through the thing on a Gopower dyno.. One change was for an Erson cam they sent us to try. (was an incrementally larger cam on all numbers) . The first cold fire up and warmup tha thing sounded like a killer.. Engine was probably 25% snappier off load.. So first pull, the torque curve was off by over 100ftlbs.... so back to the dial indicator and degree wheel.. was right were it belonged, so... bumped it up 2º and it did not improve.. Really did not work on that cam any further.. As this was running in a drag boat, there was no room for the impaired torque curve.. I am used to trading torque for HP and vica versa but this cam was only a tiny bit larger but made a giant difference.. Probably should have worked on it more but like you, I was pretty unhappy on that session...
Thinking about my previous comment, I think i would install the original cam and dyno again, i think this would also showcase your porting skills and make an awesome comparison.
Are the heads too big for the camshaft engine combo?
What ended up being the answer? I forgot but others mentioned Richard Holdener situation where 50 ft lb was "missing" and it was due to having no extensions after the collector.
Intake plenum volume has a treshold, where it stops pulling new air through the carb, and only feeding the cylinders with the mist that lingers in the plenum. You should've taken it to the 9000, just to see how it reacts. Second thing is the lobe separation/exhaust valve timing. When you are running high octane fuel, it burns slowly and if the exhaust valve opens before the fuel has done it's job, the power output goes down. This is backed by the smaller header, so when there's more back pressure in the exhaust, it makes more power, keeping the combustion inside the chamber. One quick fix is bigger lash on the exhaust valve, another is faster burning fuel. but both of these won't help on the plenum volume. If you have a spacer on the intake, take it off and try again.
Eric, 1st I would test another dyno. If it duplicates or is close to the same results then I’d look at the cam lobes.
Is the cam lobe design ( low shock) bleeding off to much cylinder pressure down low hurting the torque but carrying out up top to make good power beyond 7500rpm? Just a thought. 🤷🏻♂️
my guess is intake modifications specificly runner length. might flow better, but maybe the modification messed with the pulse in the runner.
I would verify those numbers elsewhere if possible. It could have been a loading issue. If it does turn out the same, my personal opinion would be the air speed. Im no porter, but have some experience with it. If by changing the short side it dropped a ton of air speed, it may have hurt it enough to need the higher rpm to meet same demand.
I always wondered how close them cam cards actually were on the boxes .
My buddy brought his blown big block Chevy to the dyno, the first run it made 400 horsepower. After almost puking they went over the motor, found nothing wrong mechanically, pulled the plugs and they all looked weird, so they changed the plugs and picked up 300 horsepower with no other changes, sometimes it’s the simple things that you overlook that make the most difference. After that the dominator carb wouldn’t work and after a few pulls they called it quits
I looked some more at your sheet , the dyno correction is drifting or cal is off, look at your torque , it peaks then remain flat for over 1500 rpm , I think the dyno has a strain gauge issue. He needs to rehang his cal weights.
I'd look into the rod ratio at high rpm. Unless it was a raised deck block, that pass poor rod ratio of a 400 can kill torque while making great power with a similar stroke in a taller block.
Hi Eric, brave video sir. What did you do to the ex port? Try a manifold with way less volume, and l dont get the small cam durations.
Colin Lloyd, Headsense Engines Heads,, Aust
I would be mad about going to an engine dyno and their equipment being messed up and not working correctly. I my head I am thinking, well if the basic peripherals aren't working, how can I trust what the dyno is telling me? I understand each dyno is different, and for comparison sake using the same one is the best idea, but in this case I'd be tempted to find another dyno.
Man I was just typing out a comment that the cam should be checked and then you go into the details of having it checked. I've got a set of your dragon slayers from 2016 going on my 427 with a Jones 254/256 solid roller an planning on dynoing it before installing in the car.
I build a little 355 engine I called Summit Racing and they told me to put a 465 lift cam in it with 224 intake 224 exhaust I did what they told me to do Andy engine would fly it was fast as hell I went with 10.8 compression ratio that was enough for the street your truck would jump sideways the people at Summit Racing know what they're talkin about but I like the video man keep up the good work
It seems you`ve built an open wheeled circle track motor, more compression, more cam shaft and crank it to 8500+ and that pump would scream. I hosed myself like this about 25yrs ago with a superlate model asphalt motor. I replaced an 034 bowtie casting 207cc intake runner with a 220 RHS head, with a solid roller instead of a solid flat tappet that was in the 034 head. Lost maybe 60ft/lbs of torque and only gained 18hp, it was sleepy under 5500 and reached max hp at 7700rpm. Respectfully I believe the loss of torque was the cylinders weren`t being filled, so I had the intake valves increased to 2.050 on the bowtie heads (new rule change) and bowls blended, kept the solid roller and that was what we needed. Got back 90lbs torque (+30 net) and about 60 hp (48Hp net). For what it`s worth my friend, good luck and don`t beat yourself up too much.
I'm definetly no expert but on my bb 67 Camaro i had 30 years ago and my pressent day 512 ci 73 challenger my lift on the exhaust valve is higher than the intake. I picked this cam based on a formula I found on the youtube channel Myvintageiron. his formula was pretty in depth. You may want to check it out.
I would get that cam measured out, nevermind lol.
I think 8 degrees and that LSA change was enough to do it. The valve opening at TDC combined with a different port shape could be really hurting low speed flow
Have you heard of the IOP program? Might be worth checking out?
We know the AFR227 you ported was good. If we say 233 ccm / 5.1 inch length, we get average CSA of 2.79 inch square.
A 2.08 valve is 3.4 inch square and 2.79 / 3.4 = 82 % as Area and 90.6% as diameter.
I belive this is high enough and this latest engine has way more than this. That may kill torque due to low port energy.
Also, I must remind all that Darin Morgen has warned us all about touching the "hyper critical SSR" on some heads.
ua-cam.com/video/qhsTQn0uUOQ/v-deo.html
ua-cam.com/video/lcxp9ufC1DY/v-deo.html
AFR @20:34 show way lean in the midrange. Looking at the torque curve, it does taper of.
A 7* later IVC (best I can figure based on the cam numbers and assuming you've got them both 4* advanced) is gonna shift power up substantially, and kill the low end. I'm headed to the redemption video now to see what you learned.
I’m guessing that the dyno is not exactly correct and the headers are hurting more than we really expect them to. But my explanation for the power loss is the intake manifold. Large intake manifold will definitely kill torque and make big rpm’s up top!!! JMO. Great video.
Having looked at this over and over, I have an ide and it is related to the timing of the cam. I am conserned with Smokey Yunicks XO or Cross over point which is very important. This is when both valves are opened the same amount around TDC. XO at TDC is "Straight up".
You say you have 248 degrees in and 253 degrees exhaust on a 108. The extra early exhaust valve opening can be confusing as it covers up what overlap wise, this is like a 248/248/106.75 degrees cam. You have installed it at 107.5 degrees and ergo TDC lift confimes that the cam is way retarded with 0.98" lift on the intake valves and 1.16" lift on the exhaust valve in TDC.
This usually kills torque and makes the engine rev.
We always start with exhaust valve lift 66% - 75% of the lift that the intake valve have in TDC.
As a very rough guide; 0.98 + 1.16 = 2.14 / 2 = 107. Then +/- 15 for 1.27 for intake and 0.92 for exhaust.
0.92 / 1.27 = 74.5%. His would be mye least advanced starting point. :) Just my 2 cents.
I doubt it one single thing. Majority of it is likely in the camshaft. What’s the dynamic compression with both camshafts?
My last engine a cleveland 408 with unported CHI heads and manifold with 11.5 comp and 262/272@50 and 721 lift it dynoed from 4500 made 429 hp and 501 lb of torque and peak torque 546.5 at 5500 and made 655 hp @7000.This was done with a superflow 902,but my engine builder says that his dyno is rated differently to a lot of dynos,being a drag race builder he says his hp equats to the moroso calulater,your deal doesnt sound like that weeny cam
if I remember right from the other video you put a new cam with less aggressive lobe profiles to help be easier on the valvetrain. Maybe the profile change is hurting torque? Also think the dyno having some issues that day could be a factor and would probably start there with a different dyno to confirm.
I think you are on the right path with going back to the original camshaft. The compression is a bit low. Were the valve seats ground? Lowering the compression even more? Maybe an angle mill on the heads to raise compression?
Much obliged sir for the insight.
Whats the Bore & Stroke.
Did you have an 18 inch collector extension on the headers? 108 degree lobe center on a 7800 rpm engine is kind of tight.
I feel your frustration, I invested way too much time just getting all the blue printing aircraft quality right. Seemingly everything fought me. Though it turned out blessedly well.
I'm wondering about your dyno personally.
But I think 570 torque would be maximum expectation but I'm not sure. your 50 away. As for the peak hp above the 355 is just bizarre. It would keep me up at night. I'd have to spend some money to someone like kaase identify the situation. Thus might keep me up at night. There should be a way to scale reset dyno for torque and power easily.
Erik. What size the carb.I would look at changing carb.from what I saw of the early BSFC was lean.i have run 1,000 cfm pro systems carb on similar cid engines and made 600 trq around 5100.also used 1 7/8 primary 3 1/2 collector.on a quick note did you see if it had a dead cylinder,I have had that happen and it had me itching my head.the engine didn't sound like had any misfire .found it had a closed strap on the plug
To much cylinder head. Need more compression. Your one of the best cylinder head specialist around.
I cannot remember if you degreed the camshaft, I've seen timing gears machined wrong as well as camshafts ground incorrectly. Advancing the cam timing or changing to a more narrow LSA might be the simplest trick & where I would investigate first.
It was the dyno. It went faster at the track.
I'm sorry. I do believe you had announced that. I was watching some of your older videos today & forgot what you had learned about this engine. I'm glad as it surely was bizarre results as you knew what you should expect. Gladbit worked out well. Very stout SBC and I would be very proud as I am sure you are. We'll done Eric.
Sound s to me you have a cam that makes power above your usable RPM range? Amd a merge collector with a 2.500 " cross section would work way better than a 3.5" straight?
I didn't think there was anything to make that much difference...until the intake change. I've seen big changes with them.
Hey we all have our days shit happens. Did you open the ports in the heads more maybe a loss of velocity? Maybe there is to much volume in the intake I don't know I am taking shots in the dark here.
It’s nice to watch a video about somebody telling the truth and know what he’s talking about at the same time 👍👍
Same thing happens when people start carving on Vortec heads.. You can go the other way fast and not to mention take reliability out of them and causing weak casting points and get cracks even more...
Could it be the similar issue to the story you told about the timing and the balancer being off where you had the small block with 50°+ of timing to make any power.
Seems heads are huge and cam is huge. But you the professional.lol my home built junk 406 has afr 227s and a crower solid roller 269-281 629/639 106 13-1 makes 685. With iron dart 215s 2.08 valve
My cam was smaller than yours mine is 248/256 .750/.690 108lsa. Your cam is much larger.
True idk does seem something is off. My bet is Dyno is wrong
Seems like those big flow numbers are doing what their supposed to do, making high rpm horsepower. I'm a little surprised that ring seal wasn't compromised at 7k + rpm. I saw a video of a chevy ro 406 Nascar engine running to 9000 rpm and made 930 hp with a 830 cfm carb. Hugh ports and more compression. Dyno readout started at 5500 rpm I think. I drag race a 406 that has run 10.7 at 4200da. I would use this engine in a heart beat. BTW, my cam is 278 deg intake duration, 718 gross lift. I run 12.5 compression using 55 cc 227 heads. I like your pragmatic approach to racing. Imo any porting should be followed with a dyno run or drag strip results.
Eric put all the details into engine analyzer pro. See if the torque drop is replicated in EAP.
What was the Length of the Dyno Header's Collector? What type of Carb Spacer, Open or Tapered Four Hole such as the HVH SS4150/4500-1.5A? Did you try advancing the Cam to see if it liked it? How about seeing if it liked 1.6:1 Intake and/or Exhaust Rockers?
Eric a cam I use in my 406 might help. It's a old grind from comp cams and works well. 12-906-9 . I put it in straight up , then retarded it 2 degrees and made great power.and torque.. Using out of box AFR heads , out of box Motown intake and port match to gaskets, 950cfm quick fuel, one inch HVH spacer and made upper 657Hp@ 6700 and. 538 -542 ft Torque@ 5600rpms , if I remember correctly. Shifted at 7000.
I’ve got the 12-909-9 in a 355 12:5:1 with a set of lightly ported sportsman 2 heads. Flow 285cfm on intake and the motor will run 6.50s in a 3350lb car. 750 carb
Did you check swirl on the heads as compared to the last configuration of those heads?
Vizard says a lack of swirl will knock torque and power in the head right up to peak power.
Maybe get rid of those LST lobes?
The cam in my Hemi is a 116 degree and it pulls 22ip of vacuum a old blower helper crane cam from the 70es.
Strange to be sure. Degree in the cam on a companion cylinder (6 probably) and on a back cylinder. Maybe the blank slipped while being made. Also, another dyno to back up results is pretty important to not go down the wrong path before you're too invested. I would also swing that cam timing both ways, you might be surprised at some cylinder fill harmonic or something. Lastly, if all that leads no where, I would change the cam on the dyno to a known one and eliminate 1 of the variables. Look at the bright side, maybe what you learn leads to a better 60 ft on your truck by finding torque down low without hurting top end! Good luck.
Despite the numbers it must have lost cylinder pressure, unless the dyno is working different from last time. With sensors being bad and the jump at the start, it is a justified concern. Like you said it doesn't seem right. Dyno could be the reason.
This is just a thought if your intake manifold is higher than previous one and ported that has more plenum volume than the other one then would that kill the torque. But the runners are longer to so the longer runner should help on the bottom end. Another thing I was thinking to I hear a lot of racers who run 400 sbc engine either 406 or 410 like a Sprint car they run a higher compression at 13, 14, or even maybe 15:1 compression. Doesn't more compression help to especially on a bigger engine. But other than that I can't think of anything else. I don't know I don't build engines my dad does and a few people I know do. Also another thing do what's weird is should a 400 cubic inch motor should make more torque than a 350 because of the bigger bore and stroke. I don't know just a thought I figured anything helps
I'm having a hard time trusting the dyno. It clearly isn't well maintained. I understand the frustration brotha but you're certainly no idiot and I think I'd have to see similar numbers on a different dyno to be fully convinced that is a engine combination issue.
That's just my opinion though, I've never personally seen less camshaft and more cubic inches move the power up in the curve up. Good luck with figuring it out, Eric, in the mean time I think Cecil will really enjoy the 477 lol!
With your big head ports and valves sound like a Nascar cup engine, you need to get the port velocity up, for the lower rpm that you want to make power at. Come tonight to Richard Holdener podcast at 7pm Pacific and ask about your engine combination
You ever think that you last build was just spot on and you just changed the harmonics and ram charging enough in the new engine where the usable rpm range is in the low spot of the tuning? It might not be the new engine is bad but the last engine was spectacular. I would keep changing intake and exhaust lengths until it is back in tune, I might even change the cam because the cam, exhaust, and intake seem to not be matched in their hmm ..... tune timing?, harmonics, or ram charging? I'm sure there are proper words for that but I'm not remembering them right now lol.
It was the dyno. It went faster in the truck.
@@WeingartnerRacing Good, I'm glad, Thanks for the reply.