DUDE! I have been swinging and missing at my tune on this SBC of mine for well over a year now. Fouled plugs, swapping jets, power valves, timing, fuel octane. All along the way I have left he vacuum advance alone. I watched the video yesterday and today I hooked that advance up to full time vacuum on the carb base (650 double pumper holly) and I'll be dipped. I had a blast driving this ole Rickshaw wagon around today. Runs much much better now. This video here just confirms my actions today. Thanks for the tip to the direction I needed with this tune.
Once you follow the correct procedure to select the correct power valve there should be no reason to change the size! If you don't have a good book on Holley carbs, you should buy one.
When these cars were new they only got 8 to 10 MPG around town, and around 12 to 14 on the highway. Believe me, I was there. That is for the small block versions, big blocks got much less than that. You are spot on right about using vacuum advance and dialing the AFR's and maxing out the timing. My 505 in the 73 Charger, a very heavy car, can get up to 15MPG on the highway. Most people do not understand how to dial in a powerful engine for max power, which goes hand in hand with max efficiency.
Fuel mileage has a lot to do with how it's maintained and driven. I can get 13.5 out of my brothers c20 truck, and he gets 10. He's owned it for 40 years
Botton line, what Chris is saying is true. Automakers and the EPA have known this for YEARS. The reason the EPA forced automakers to use ported vacuum for vacuum advance is the fact that engines produce lower emissions at idle with a lower amount of advance.
@lollipop84858 I also like being free from the Gestapo. Everything we do now is under some form of control. And if we don't, we are fined and / or imprisoned. Mostly under a democrat regime.
I’ve been experimenting with these same things. I hooked my mightyvac up to the vacuum canister to find out how much vacuum the engine actually wanted. Then I looked at how many degrees of advance that gave me. Then I adjusted the canister to give me that same amount of vacuum advance. Let me tell you the engine on my old truck ran so smoothly I literally thought it had died at the intersection - no joke. This took my 12-13 mpg 1969 F250 to 19-20 mpgs.
Thanks Chris for letting the cat out of the bag, I used the same timing and vacuum advance technique on my 73 Plymouth Satellite with a 318 , stock 2 barrel and it ran strong back in the day. Only mod was headers and 3.91 gears. Everyone could not believe it was a 318!
A good friend of mine thought that his 1986 Dodge Ramcharger was just completely gutless despite being "cammed" as the previous owner had told him. I spent 3 days fixing vacuum leaks, cleaning and rebuilding the Edelbrock carb. to go back on the Edelbrock intake, set the initial ignition timing to slightly advanced instead of slightly retarded and made sure the carb. got the correct fuel pressure. He was stunned to see that with just a few quick revolutions the truck fired right up. I hooked checked over as much as I could and hooked the vacuum advance back up. After the cleaning, fixing and tuning the truck went from fighting to start, fighting to go, fighting to get to 50 MPH on flat ground.....Suddenly that 318 and 4 speed manual 4x4 was doing 70 MPH on the interstate and he could cleanly take off in 2nd instead of relying on the super low 1st. Even managed to improve his fuel economy by a noticeable amount too. That said, not his daily now so we can swap out the worn out 318 with something more correct for his plans.
Excellent videos Chris! I've been mirroring your experiences while tuning on my Ford 289 over the last several driving seasons. Everything you reference applies to all makes and models; and fuel injected ECU level performance can be achieved once you understand how the vacuum advance works in light load; lean conditions. Tuning vac advance in harmony with the centrifugal advance curve for your specific engine build yields a cool running highly efficient engine that is snappy on throttle and coasts down the freeways. Many hot rodders are running large radiators, and a marginal tune in consequence to not utilizing the information you've detailed so well here. One tip I will add in context of this video: As you optimize the centrifugal timing curve and vacuum; you may need to adjust the idle circuit, the accelerator pump nozzle size, main metering circuit and/or secondary jets to fully realize a unified optimal tune... Each step you take may require a trim on the vac advance adjustment of centrifugal curve; such that you'll achieve optimal AFR from idle to WOT. Some might reply; that's what Fuel Injection is for... but it is an extremely rewarding experience when you put in the effort; and makes driving these classics anywhere, and in any conditions; a true dream.
nice video Chris! I can say it again get one of those Progression Ignition Distrubators. They have a vac sensor so u dont need that much vac for advance. And you can do litterly every timing on every rpm/load. Its nuts!
Great video Chris. Long time fan of your channel, but first time commenting. Glad that you stressed that every engine is different. That's definitely the key. The more you stray from the factory build of the engine, the more the fuel and spark requirements change. Especially when there's more valve overlap from a bigger cam, causing reversion in the intake, pulling exhaust gases back into the cylinder, diluting the intake charge, which is why the engine wants more ignition advance. Same with light throttle, low load conditions. You need much more ignition timing to create ideal cylinder pressure for the engine to run efficiently. Give the engine what it wants, not what you think it needs.
My advance has adjustable vac pod. Had no idea that was possible. Thanks. Also Blue Print suggested a cold plug which works at the track. But only figured that out after fouling plugs. Hotter plug, no problem for cruising. Great info Chris
Chris really does have a good way of explaining things, and he’s totally correct. People could definitely really improve the performance of their engines by listening to him. I didn’t know who he was until people quoted him on my site. Anyway good shout out to chris.
Best video I have seen. Old timer taught me exactly what you were saying. Set base timing with maximum vacuum at idle, retard 2°. Advance hooked up to manifold vacuum. Run hard under load, retard further if pinging. Very impressed with your video. Learned a few new things, and explained things I barely understood
Great demo. I agree, vacuum advance is the way to go. I notices some hesitation on acceleration, that's caused by all that timing dropping out abruptly. had the same problem. I installed an adjustable metering valve in the vacuum line to delay or slow down that vacuum drop rate. No stumble or flat spot, acceleration is snappy and smooth. also help with stumble off idle. adjust to suit. i used a metering valve off a fish tank bubbler.
Your video has me scratching my head! I’ve always ran ported vacuum, with about 16 degrees of initial timing. According to my timing light, timing just the mechanical and initial, I’m at 36 degrees. That’s supposed to be where a small block Chevy is supposed to be happy .I’ve even drilled the primary throttle blades, to get my idle transfer slots in the right place. I’ve done multiple mods to the engine, and it doesn’t seem to work any better. I don’t drive the car much. It hasn’t been on the road for 3 years, but I’ve been watching a few videos about using manifold vacuum, instead of ported vacuum, and now I’m giving it a lot of thought. Thanks for sharing your experience! 👍
Chrysler vacuum pods are often marked for the amount of advance they will give. In the video I posted yesterday, I showed an example labeled 8.5. Depending on the year and model, there was a wide range that can be found and it's easier to tune when you know what you are starting with. You never showed how you are limiting your mechanical advance. I also give one example of how to limit mechanical advance in yesterday's video. Timing is a complex process that involves a depth of understanding that is far ahead of most hobby builders. Thanks for sharing your insights and how they relate to one specific build. Nice car!
It makes sense once you think it through. Back in the day everyone tuned their cars by feel/ear and actual driving results. All this said, I don't run carbs any longer so this may not have as much of an impact although I will have to try some of this out on my 416 stroker in my 73 Cuda.
Great video and I totally agree with connecting the vacuum advance to full manifold vacuum. However, too much timing can cause engine surging which is most noticeable when you let off the gas and coast at highway speeds; so you may need to tune the vacuum canister for slightly less advance.
I’ve been waiting for someone to explain this to me in a way I understand, great video. I’ve watched other good channels but they skip some of the basics. 👍.
Glad I watched this video (after watching the one before this)answered a lot of questions I had , so looks like I don’t have to be worried about a lot of idle or cruising timing as long as when I bring total timing in,when vacuum drops out I should be in the 34-36 range or right before pinging, I think I’m starting to get this, you have done the best job I have seen explaining the whole package😀😀, please reply so I know I’m on the right track, thank you(DRF)
Nice video I have one question I may have missed is your distributor vacuum advance hooked to manifold vacuum or ported vacuum? Thanks again it was a great video I enjoyed watching it learned a lot.
Can you do more videos on tuning like this. Timing and carb please. This is where I have the biggest problem. Is stock different? There’s so many videos but yours is pretty in dept. For example, I didn’t know how to figure out what to set my timing to. In your video you said “advance until you hear pinging then back it off and take it for a drive. If you hear pinging, timing is too high”. That’s exactly what I needed. I really appreciate you making these videos!
I think part of the confusion people run into on the ported vs manifold vacuum debate, is the manifold vacuum nay sayers are already not running enough initial timing. If you're going by off the cuff recommendations of 12-16 deg initial and a slower advance curve ( heavier springs ), the mechanical advance is too slow off idle to provide good driveability. The key Chris touches on here is treating each engine on it's own merits and tuning to best idle vacuum with the vacuum advance hooked up, granted a properly tuned carb. Ported vacuum WAS introduced in the late 60's to reduce off idle emissions passenger cars and light trucks, particularly because it was seen as an effective way to help counteract emissions industry wide when common circumstances were that your average driver would skimp on maintenance ( just like today ) , often waiting until they developed a driveability problem on their vehicle before they would perform recommended maintenance.
What is the method of determining what "Base Timing" value you set your engine at? 22° ? How did you chose that 22° or rather How did you determine your engine wanted that value? Is it dictated by your Max timing? Thanks (Great Video too and killer cars)
Awesome video Chris. That Tall John Science sounds like it works. I think I remember home saying he got 18mph in his 440 ton grille. When I heard that I said, “WTF?”
Wait, there's a screw adjustment in the vacuum pod?! I had to actually go check my Road Runner to see if it wasn't April 1st. Never touched it in my life, but I think that's about to change. Thanks for the video!
Great video!! I don't understand why almost nobody talks about initial timing. Everyone one talks about total or vacuum. Most of your time is spent on initial and vacuum.
Interesting. I have mild 318 in my 69 Satellite. I got 19mpg last summer, but I think there is more. I'll have to check vacuum timing next summer, yeah we already have snow here...
Goldmine of forgotten tuning information. Thanks for sharing and making this video, Chris. I do have a question about that pistol grip shifter handle- as in what’s going on with it in the Charger since the car is an automatic? Is it for a parking brake or overdrive unit? What gives? Thanks in advance.👍🏻
REF 20:21, How does one get total mech advance of 34 degrees, at 1040 rpm, unless the mech advance has been locked out at 34? I thought he sets Max mech advance at 1800 rpm?
I keep forgetting the younger folks have never seem a distributor vacuum advance or ported vacuum takeoffs on a carb and all that pre fuel injection stuff…yes I’m feeling old.
What's your opinion? I daily a carbed rig and I use ported. My problem is the hei distributor has a large timing curve, so I can't set my base as high as I want or it'll ping when I'm towing. The ported helps a lot in town driving but I have to unplug it to drive in the mountains, towing, because of pinging. On my old Chevy that had points, the distributor curve had less total advance, and I ran a lot of initial and hooked the distributor to ported vacuum and it seemed to work great. Not so thrilled with the hei distributor. I liked my points but I have had really bad luck with new manufacture points. The old ones I found in the junkyard last much better.
Some people claim that different weights limit the amount of advance on a GM HEI distributor, but the sure fire way to shorten the amount of advance is to take the distributor apart by knocking out the roll pin that secures the drive gear and pulling the shaft out to access the limiting slot and pin under the mechanical advance mechanism. You will need to get or make a bushing to fit over the pin to shorten the amount of advance travel. You may have to open the sides of the oval slot with a dremel or such for bushing travel clearance. The plate is hard steel, too, so takes a bit of effort to grind the clearance. A less complicated effort for your application might be to use heavy advance springs and even lighten the weights if necessary so that the mechanical advance will never reach it's fully extended limit at the rpm that you turn the motor to. You could probably get your initial timing where you want it that way.
How do you tune an engine that a very long connecting rod like a 351m Ford? Would you add more total timing or advance initial? I'm running a HEI distributor on this engine and I have put a curve kit in it with the middle weight springs. Should I go ligh 23:03 ter on the springs? Also this engine is cammed and 4 barrel carb, 750 edelbrock. Stock heads that have been worked over. .020 head gasket and zero deck flat top forged pistons
Thanks for all the info. I have 351c 4v. My engine pings when I have my vacuum connected at high load acceleration. But if I disconnect the vacuum it won’t ping. What can be causing that. Thanks.
Chris your performance camshaft (with a lot of overlap) bleeds off compression at low engine rpm and obviously more at cranking speeds. So at cranking speed and below peak power (at higher rpm) the compression ratio isn't 11:1 as its being bleed off by the large overlap. On a high torque low rpm camshaft 11:1 would definitely kick back on the starter motor if the static timing was kept at 22° BTDC. With a performance cam though, yes, it makes sense and is viable. I gather that you're using manifold vacuum for the vacuum can and not ported vacuum.
I feel ya. I had to take my non daily driver out because the daily was in the shop( repairs beyond i wanted to do) found myself leaving it out of sport setting . Lol.
Great info. Just subscribed. If my distributor does not have hex have old round diaphragm. I'm I able to switch out? I have a mild cam on my old c10 and want to calibrate after watching your video
Thank you very much for the info there Chris that is a a good thing to do to get it more efficient and excellent explanation of how it works and why and you'll turn a lot of people on to that advantage but like you said it takes the right vacuum advance in that is kind of an issue if you use the OEM Chrysler it doesn't work real well but get an aftermarket one and hopefully they still make them that's the problem that old stuff it's tough to find it
PLEASE READ: Hey Chris, thanks for your detailed explanation. Can you address this question please ... What's your thoughts about detonation and cylinder temp? Advancing the timing will fire the fuel mixture before TDC earlier (as you have it set up once the motor is running). So, as the efficiency of the burn increases you use less fuel (leaner mixture) to produce the same power level, which means a (less fuel usage, more efficiency & better MPG). Does not the leaner fuel and advanced timing increase the cylinder temp which could lead to melting a piston? Since higher compression requires more octane is that not the perfect storm? I mean: high compression + higher octane + lean mixture + advanced timing = higher cylinder temp? which may cause melted piston. Am I all wet here? The reason I say this is I melted a piston doing exactly that. Since then, I usually run my engine a bit fat on the fuel mixture to keep the cylinder a bit cooler. I would appreciate your comments. **** An interesting test would be to use an Infrared Thermometer Temperature gun on header right at where it exits the head and measure the exhaust temp with STOCK settings and then with YOUR settings to see if the burn is higher or lower temp.
When I would time my engine with a vacuum gauge I would connect the gauge to a manifold source, and then advance the timing to maximum vacuum. Then back the timing off one inch vacuum from max vacuum because if I left it at max vacuum my car would start pinging. Since the classic vehicle I own now is a TBI engine I time it according to the way the factory requires.
Great video, question, should you not plug up your vacuum line when unplugging it from the vacuum advance canister when setting base timing? I may be wrong, but are you not creating a vacuum leak which causes a rough idle while you are setting base timing. When I disconnect my manifold vacuum advance when doing base timing, I always close off that pipe with a plug or screw to keep a smoother idle for accurate base timing. Then once set, I add the manifold vacuum back onto the canister which adds advance and smooths out idle and slightly increase rpm.
@@junkerup Understandable. I was there and seen with my own eyes and couldn't believe it. lol. Not to mention pulling over hills and I couldn't keep up. Truly was amazing. Could be a pretty cool video to prove it.
What about the "allen headed bolt" inside the vacuum advance for adjustment's. And the different degree mark's on arm and small block & big block difference, I made them there mistake's
After watching this video and the last one from yesterday I’m going to do this to all my ford trucks bc I don’t have any mopars and I wana see if can get more fuel mileage on my big block 79
I have a bone stock '70s slant six with a carter 1bbl. I've had the vac adv plugged into the carbs ported port. The port on my intake manifold had a bolt in it. I found a vac line insert for the manifold and am now running the vac adv there. My question is what do I plug into the ported vac on carb? Right now I just have it capped off.
My buddy had a '66 Chrysler convertible that had a manifold vacuum gauge on the center console (automatic trans). He would race against my '64 Galaxie XL (390 auto trans 1st car). Both would just hunker down when the kickdown engaged and we flew through the blacktop.
Hey chris, first up thankyou for all these videos mate i find them very interesting. I was wondering would this could be applied to a triple weber carb set up. Currently got no vacuum running from the dizzy but still have the module on the side of the dizzy. Thanks mate
@@junkerup alright cool thanks chris, and thanks for getting back to me so quick to. Had to ask cause im still learning 👍👍 i'll let you know how it all goes once im out of hospital and can work on the car again
My 67 Coronet has a wimp 383. Low compression, Low vacuum signal. I run 20 inital and use a FBO lockout plate locked out at 14 degrees. 34 total. I hook up the vacuum can and it detonates it brains out! The last owner had a MP Distributor that made tons of timing. To drive it at 65 mph you had to set base at 6 degrees. I chucked the distributor and bought a reman mom mopar unit. Used FBO plate set to 14 and cranked up intial to 20 , 22 ish. Plug in the can and it`s a train wreck!
Years ago I bought a '68 Polara 500 with a 383 two barrel. The motor was SO carboned up that it pinged and rattled terribly. After blowing all that carbon out I drove that car for many years. I later added a Mopar electronic ignition conversion, Edelbrock intake, Holley carb, & dual exhaust. It was strong and was never finicky for high octane after cleaning the carbon out. Did you try Seafoam or something similar?
Maybe your carburetor is too lean at part throttle operation(?) Coolant system not full(?)... Make sure to use a coolant RECOVERY bottle to keep system FULL.
Also, if using a stock or very mild cam I would use the ported vacuum source with the 20° initial timing and I would expect it to need more than 34° of total.
I've often argued that non-emissions engines should run manifold vacuum. That way you're getting ignition advance at both idle AND cruise speeds. Why not have both? What's wrong with having lots of advance at idle? You can thin out the mixture too and have a nice lean, clean idle.
If you want to run even more initial timing but experience starter kickback, don't power the ignition until after the starter is already spinning the engine over.
Let me know your thoughts on this. I had a SBC built. The builder tuned the engine on the dyno and said my engine likes 38* max advanced timing. Now I don’t remember what he set the base timing at. But after installing the engine I couldn’t keep the plugs clean when cruising around town. They would foul out jet black soot and at idle you could hear the engine loading up. I met another guy that works more with racing engines and he said I didn’t have enough initial/base timing. So he ran a test on my engine first and then we took my distributor out and he removed the vacuum advance and the mechanical advance and we locked it out at 38* all the time. I have enough valve over lap to do this with zero cranking issues. Spins right over. That made such a difference that I can’t keep my tires from spinning. (Smoke show) After that I took my car to a chassis dyno to see if more timming would help. From 38* to 40* no HP gain. Then 38* to 36* I lost around 6hp So why would I go back to a vacuum advance and a mechanical advance system? I had a 383 stroker TH350 transmission 3000 stall 3.73 gears Engine only on dyno yielded a little over 510hp and 525tq I am running on 87 octane fuel at 10.2:1 compression. Idle vacuum in park 15/16 Engine temp 180*
Good info! Are you running mech secondary carbs? Is there a reason to run vacuum secondary? I get a lot of "what" and very little "why" or "when" on this issue.
My 69 440 New Yorker got around 12mpg on a mechanical Holley 750... without the vacuum advance hooked up. Time to get tuning and do it right. Thanks again.
I have a 318 in a 1985 Ramcharger I bought for a turd project. I dingleballed the cylinders and threw on some rings and bearings, a lumpy cam, timing set, oil pump, warmed over factory heads with bigger SS valves and some self-porting, 4 bbl. intake & carb, headers....all the usual goodies. Oh, and a Mopar performance distributor with removable/adjustable pods? that limit mech. advance. It runs best with 22° initial, and my adjustable vacuum advance puts out 13°, so 35° at idle, then I have the mech. advance set at 15°. I'm getting some ping under load, so I may have to adjust my vacuum and/or pull some mech. out. But, I totally agree.....manifold vacuum for the vacuum advance for economy, shit & git, and overall drivability. Previously, I was all about ported vacuum.....I've seen the light! Good stuff! Thanks!
Chris you guys run 91 octane in Nevada ? With this Cali fuel it’s tough to get cruise tip in without ping with vacuum, I do like the bottom end and idle feel with vacuum, I might try limiting vacuum can.
15° static + 15° vacuum + 5° mech (if at all) = 35° at highest vacuum (say 20~30% throttle?!). Seems like a lot way early, but at wot vacuum is zero remaining only static + mechanical = 32~35° max. So total advance has a dip in between the vacuum max and wot. Is that so?
DUDE! I have been swinging and missing at my tune on this SBC of mine for well over a year now. Fouled plugs, swapping jets, power valves, timing, fuel octane. All along the way I have left he vacuum advance alone. I watched the video yesterday and today I hooked that advance up to full time vacuum on the carb base (650 double pumper holly) and I'll be dipped. I had a blast driving this ole Rickshaw wagon around today. Runs much much better now. This video here just confirms my actions today. Thanks for the tip to the direction I needed with this tune.
Stunned......
Timing definitely helps to get it up in the ketchup........just keep er between the culverts
Once you follow the correct procedure to select the correct power valve there should be no reason to change the size! If you don't have a good book on Holley carbs, you should buy one.
When these cars were new they only got 8 to 10 MPG around town, and around 12 to 14 on the highway. Believe me, I was there. That is for the small block versions, big blocks got much less than that. You are spot on right about using vacuum advance and dialing the AFR's and maxing out the timing. My 505 in the 73 Charger, a very heavy car, can get up to 15MPG on the highway. Most people do not understand how to dial in a powerful engine for max power, which goes hand in hand with max efficiency.
Fuel mileage has a lot to do with how it's maintained and driven. I can get 13.5 out of my brothers c20 truck, and he gets 10. He's owned it for 40 years
Botton line, what Chris is saying is true. Automakers and the EPA have known this for YEARS. The reason the EPA forced automakers to use ported vacuum for vacuum advance is the fact that engines produce lower emissions at idle with a lower amount of advance.
Less advance forces the engine to run hotter, which cleaned up alot of the emissions the EPA tested for.
F the EPA
@@jts9120 You got that right ROFL definitely with a capital "F"
@@jts9120 f the EPA? You like hunting and fishing? Why hate the very agency that helps preserve that for you and your children to do the same?
@lollipop84858 I also like being free from the Gestapo. Everything we do now is under some form of control. And if we don't, we are fined and / or imprisoned. Mostly under a democrat regime.
I’ve been experimenting with these same things. I hooked my mightyvac up to the vacuum canister to find out how much vacuum the engine actually wanted. Then I looked at how many degrees of advance that gave me. Then I adjusted the canister to give me that same amount of vacuum advance. Let me tell you the engine on my old truck ran so smoothly I literally thought it had died at the intersection - no joke. This took my 12-13 mpg 1969 F250 to 19-20 mpgs.
What engine is under the hood in your F250?
@@matthewmiller2268 360 FE
Thanks Chris for letting the cat out of the bag, I used the same timing and vacuum advance technique on my 73 Plymouth Satellite with a 318 , stock 2 barrel and it ran strong back in the day. Only mod was headers and 3.91 gears. Everyone could not believe it was a 318!
A good friend of mine thought that his 1986 Dodge Ramcharger was just completely gutless despite being "cammed" as the previous owner had told him. I spent 3 days fixing vacuum leaks, cleaning and rebuilding the Edelbrock carb. to go back on the Edelbrock intake, set the initial ignition timing to slightly advanced instead of slightly retarded and made sure the carb. got the correct fuel pressure. He was stunned to see that with just a few quick revolutions the truck fired right up. I hooked checked over as much as I could and hooked the vacuum advance back up. After the cleaning, fixing and tuning the truck went from fighting to start, fighting to go, fighting to get to 50 MPH on flat ground.....Suddenly that 318 and 4 speed manual 4x4 was doing 70 MPH on the interstate and he could cleanly take off in 2nd instead of relying on the super low 1st. Even managed to improve his fuel economy by a noticeable amount too. That said, not his daily now so we can swap out the worn out 318 with something more correct for his plans.
Excellent videos Chris! I've been mirroring your experiences while tuning on my Ford 289 over the last several driving seasons. Everything you reference applies to all makes and models; and fuel injected ECU level performance can be achieved once you understand how the vacuum advance works in light load; lean conditions. Tuning vac advance in harmony with the centrifugal advance curve for your specific engine build yields a cool running highly efficient engine that is snappy on throttle and coasts down the freeways. Many hot rodders are running large radiators, and a marginal tune in consequence to not utilizing the information you've detailed so well here.
One tip I will add in context of this video: As you optimize the centrifugal timing curve and vacuum; you may need to adjust the idle circuit, the accelerator pump nozzle size, main metering circuit and/or secondary jets to fully realize a unified optimal tune... Each step you take may require a trim on the vac advance adjustment of centrifugal curve; such that you'll achieve optimal AFR from idle to WOT. Some might reply; that's what Fuel Injection is for... but it is an extremely rewarding experience when you put in the effort; and makes driving these classics anywhere, and in any conditions; a true dream.
What initial timing do you use for your 289?
nice video Chris! I can say it again get one of those Progression Ignition Distrubators. They have a vac sensor so u dont need that much vac for advance. And you can do litterly every timing on every rpm/load. Its nuts!
on your Phone*
Great video Chris. Long time fan of your channel, but first time commenting. Glad that you stressed that every engine is different. That's definitely the key. The more you stray from the factory build of the engine, the more the fuel and spark requirements change. Especially when there's more valve overlap from a bigger cam, causing reversion in the intake, pulling exhaust gases back into the cylinder, diluting the intake charge, which is why the engine wants more ignition advance. Same with light throttle, low load conditions. You need much more ignition timing to create ideal cylinder pressure for the engine to run efficiently.
Give the engine what it wants, not what you think it needs.
My advance has adjustable vac pod. Had no idea that was possible. Thanks. Also Blue Print suggested a cold plug which works at the track. But only figured that out after fouling plugs. Hotter plug, no problem for cruising. Great info Chris
Chris- Both you and Thunderhead 289 nailed it, its a process most don't understand👏
Chris really does have a good way of explaining things, and he’s totally correct. People could definitely really improve the performance of their engines by listening to him. I didn’t know who he was until people quoted him on my site. Anyway good shout out to chris.
Being able to easily fiddle with the ignition timing, was the most beneficial thing about fitting a Holly EFI to my friend's Chrysler 300.
Best video I have seen. Old timer taught me exactly what you were saying. Set base timing with maximum vacuum at idle, retard 2°. Advance hooked up to manifold vacuum. Run hard under load, retard further if pinging. Very impressed with your video. Learned a few new things, and explained things I barely understood
Great demo. I agree, vacuum advance is the way to go. I notices some hesitation on acceleration, that's caused by all that timing dropping out abruptly. had the same problem. I installed an adjustable metering valve in the vacuum line to delay or slow down that vacuum drop rate. No stumble or flat spot, acceleration is snappy and smooth. also help with stumble off idle. adjust to suit. i used a metering valve off a fish tank bubbler.
Your video has me scratching my head! I’ve always ran ported vacuum, with about 16 degrees of initial timing. According to my timing light, timing just the mechanical and initial, I’m at 36 degrees. That’s supposed to be where a small block Chevy is supposed to be happy .I’ve even drilled the primary throttle blades, to get my idle transfer slots in the right place. I’ve done multiple mods to the engine, and it doesn’t seem to work any better. I don’t drive the car much. It hasn’t been on the road for 3 years, but I’ve been watching a few videos about using manifold vacuum, instead of ported vacuum, and now I’m giving it a lot of thought. Thanks for sharing your experience! 👍
Chrysler vacuum pods are often marked for the amount of advance they will give. In the video I posted yesterday, I showed an example labeled 8.5. Depending on the year and model, there was a wide range that can be found and it's easier to tune when you know what you are starting with. You never showed how you are limiting your mechanical advance. I also give one example of how to limit mechanical advance in yesterday's video. Timing is a complex process that involves a depth of understanding that is far ahead of most hobby builders. Thanks for sharing your insights and how they relate to one specific build. Nice car!
Smart lady. Exactly what you said- "one specific build"👍
Understanding comes a lot easier when explanations start with the "why" before proceeding to the "how".
Hey! Chris.
What a lesson to remind.
Each engine is unique and deal with, just like you' said.
Need to practice 😂
Thanks again.
Chhis I'm 63 years old love your stuff I hope you care about us old guys
It makes sense once you think it through. Back in the day everyone tuned their cars by feel/ear and actual driving results. All this said, I don't run carbs any longer so this may not have as much of an impact although I will have to try some of this out on my 416 stroker in my 73 Cuda.
Solid Gold video Chris, your expertise is greatly appreciated.
That was a good one, you spent a lot more time on this subject then most people, Thanks.
Great video and I totally agree with connecting the vacuum advance to full manifold vacuum. However, too much timing can cause engine surging which is most noticeable when you let off the gas and coast at highway speeds; so you may need to tune the vacuum canister for slightly less advance.
If you learn to listen, see, feel, etc., every engine will tell you what it wants. Give them what they want. 👍
I’ve been waiting for someone to explain this to me in a way I understand, great video.
I’ve watched other good channels but they skip some of the basics. 👍.
Glad I watched this video (after watching the one before this)answered a lot of questions I had , so looks like I don’t have to be worried about a lot of idle or cruising timing as long as when I bring total timing in,when vacuum drops out I should be in the 34-36 range or right before pinging, I think I’m starting to get this, you have done the best job I have seen explaining the whole package😀😀, please reply so I know I’m on the right track, thank you(DRF)
Nice video I have one question I may have missed is your distributor vacuum advance hooked to manifold vacuum or ported vacuum? Thanks again it was a great video I enjoyed watching it learned a lot.
Can you do more videos on tuning like this. Timing and carb please. This is where I have the biggest problem. Is stock different? There’s so many videos but yours is pretty in dept. For example, I didn’t know how to figure out what to set my timing to. In your video you said “advance until you hear pinging then back it off and take it for a drive. If you hear pinging, timing is too high”. That’s exactly what I needed. I really appreciate you making these videos!
I think part of the confusion people run into on the ported vs manifold vacuum debate, is the manifold vacuum nay sayers are already not running enough initial timing. If you're going by off the cuff recommendations of 12-16 deg initial and a slower advance curve ( heavier springs ), the mechanical advance is too slow off idle to provide good driveability. The key Chris touches on here is treating each engine on it's own merits and tuning to best idle vacuum with the vacuum advance hooked up, granted a properly tuned carb.
Ported vacuum WAS introduced in the late 60's to reduce off idle emissions passenger cars and light trucks, particularly because it was seen as an effective way to help counteract emissions industry wide when common circumstances were that your average driver would skimp on maintenance ( just like today ) , often waiting until they developed a driveability problem on their vehicle before they would perform recommended maintenance.
That’s how I learned to tune a car!
Got a bone stock 340 duster to run 14.0@97 in 4000’da
Good job! I know people that tune cars every day with hp tuners and cannot understand basic distributor ignition. Scary ain't it!
What is the method of determining what "Base Timing" value you set your engine at? 22° ? How did you chose that 22° or rather How did you determine your engine wanted that value? Is it dictated by your Max timing? Thanks (Great Video too and killer cars)
Awesome video Chris. That Tall John Science sounds like it works. I think I remember home saying he got 18mph in his 440 ton grille. When I heard that I said, “WTF?”
Appreciate you sharing your knowledge. Reminded me of what I was told many years ago. Recently subscribed, I will continue to follow you.
Wait, there's a screw adjustment in the vacuum pod?! I had to actually go check my Road Runner to see if it wasn't April 1st. Never touched it in my life, but I think that's about to change. Thanks for the video!
Great video!! I don't understand why almost nobody talks about initial timing. Everyone one talks about total or vacuum. Most of your time is spent on initial and vacuum.
Really great video Chris!
Great video Chris and thanks for sharing your hard learned pearls of knowledge and wisdom 👍
Love this guy, I’ve got a 72 d100 daily love it I don’t bag it but I drive it.
great video, would be great to see how you tune carburetors!
Awesome vid bro!! I need to watch it again sober...lol.
Always take on board your knowledge Chris thanks for sharing very helpful. Keep em coming 👍 👌 👍
Awesome Chris! I sure do wish I was closer to you to time my engine good! Roadtrip🤔?
Good stuff brother.. Thanks for the great info.. Been to many years since ive even touched any of my dizzys..👍👍
Interesting. I have mild 318 in my 69 Satellite. I got 19mpg last summer, but I think there is more. I'll have to check vacuum timing next summer, yeah we already have snow here...
Definitely could get more with it. I got almost 19mpg too with a 400 bbm.
@@aquamarine9979 That is job for next driving season :)
Jungle up what gas do you do you put in your engine for compression from 11:01 and can you run your engine on 1101 compression on pump gas
Goldmine of forgotten tuning information.
Thanks for sharing and making this video, Chris.
I do have a question about that pistol grip shifter handle- as in what’s going on with it in the Charger since the car is an automatic?
Is it for a parking brake or overdrive unit?
What gives?
Thanks in advance.👍🏻
REF 20:21, How does one get total mech advance of 34 degrees, at 1040 rpm, unless the mech advance has been locked out at 34? I thought he sets Max mech advance at 1800 rpm?
I keep forgetting the younger folks have never seem a distributor vacuum advance or ported vacuum takeoffs on a carb and all that pre fuel injection stuff…yes I’m feeling old.
What's your opinion? I daily a carbed rig and I use ported. My problem is the hei distributor has a large timing curve, so I can't set my base as high as I want or it'll ping when I'm towing. The ported helps a lot in town driving but I have to unplug it to drive in the mountains, towing, because of pinging.
On my old Chevy that had points, the distributor curve had less total advance, and I ran a lot of initial and hooked the distributor to ported vacuum and it seemed to work great.
Not so thrilled with the hei distributor. I liked my points but I have had really bad luck with new manufacture points. The old ones I found in the junkyard last much better.
Some people claim that different weights limit the amount of advance on a GM HEI distributor, but the sure fire way to shorten the amount of advance is to take the distributor apart by knocking out the roll pin that secures the drive gear and pulling the shaft out to access the limiting slot and pin under the mechanical advance mechanism. You will need to get or make a bushing to fit over the pin to shorten the amount of advance travel. You may have to open the sides of the oval slot with a dremel or such for bushing travel clearance. The plate is hard steel, too, so takes a bit of effort to grind the clearance. A less complicated effort for your application might be to use heavy advance springs and even lighten the weights if necessary so that the mechanical advance will never reach it's fully extended limit at the rpm that you turn the motor to. You could probably get your initial timing where you want it that way.
@@kyleclearwater7380 sorry- my reply was intended for your comment.
@divadyrdnal- being old beats the alternative. Let's just try to get older😁
How do you tune an engine that a very long connecting rod like a 351m Ford? Would you add more total timing or advance initial? I'm running a HEI distributor on this engine and I have put a curve kit in it with the middle weight springs. Should I go ligh 23:03 ter on the springs? Also this engine is cammed and 4 barrel carb, 750 edelbrock. Stock heads that have been worked over. .020 head gasket and zero deck flat top forged pistons
Hit the thumbs up, folks
👍👍
Thanks for all the info. I have 351c 4v. My engine pings when I have my vacuum connected at high load acceleration. But if I disconnect the vacuum it won’t ping. What can be causing that. Thanks.
Chris your performance camshaft (with a lot of overlap) bleeds off compression at low engine rpm and obviously more at cranking speeds. So at cranking speed and below peak power (at higher rpm) the compression ratio isn't 11:1 as its being bleed off by the large overlap. On a high torque low rpm camshaft 11:1 would definitely kick back on the starter motor if the static timing was kept at 22° BTDC. With a performance cam though, yes, it makes sense and is viable. I gather that you're using manifold vacuum for the vacuum can and not ported vacuum.
I feel ya. I had to take my non daily driver out because the daily was in the shop( repairs beyond i wanted to do) found myself leaving it out of sport setting . Lol.
Great info. Just subscribed. If my distributor does not have hex have old round diaphragm. I'm I able to switch out? I have a mild cam on my old c10 and want to calibrate after watching your video
Thank you very much for the info there Chris that is a a good thing to do to get it more efficient and excellent explanation of how it works and why and you'll turn a lot of people on to that advantage but like you said it takes the right vacuum advance in that is kind of an issue if you use the OEM Chrysler it doesn't work real well but get an aftermarket one and hopefully they still make them that's the problem that old stuff it's tough to find it
PLEASE READ: Hey Chris, thanks for your detailed explanation. Can you address this question please ... What's your thoughts about detonation and cylinder temp? Advancing the timing will fire the fuel mixture before TDC earlier (as you have it set up once the motor is running). So, as the efficiency of the burn increases you use less fuel (leaner mixture) to produce the same power level, which means a (less fuel usage, more efficiency & better MPG). Does not the leaner fuel and advanced timing increase the cylinder temp which could lead to melting a piston? Since higher compression requires more octane is that not the perfect storm? I mean: high compression + higher octane + lean mixture + advanced timing = higher cylinder temp? which may cause melted piston. Am I all wet here? The reason I say this is I melted a piston doing exactly that. Since then, I usually run my engine a bit fat on the fuel mixture to keep the cylinder a bit cooler. I would appreciate your comments.
**** An interesting test would be to use an Infrared Thermometer Temperature gun on header right at where it exits the head and measure the exhaust temp with STOCK settings and then with YOUR settings to see if the burn is higher or lower temp.
Not enough cylinder pressure to melt anything
When I would time my engine with a vacuum gauge I would connect the gauge to a manifold source, and then advance the timing to maximum vacuum. Then back the timing off one inch vacuum from max vacuum because if I left it at max vacuum my car would start pinging. Since the classic vehicle I own now is a TBI engine I time it according to the way the factory requires.
Great video, question, should you not plug up your vacuum line when unplugging it from the vacuum advance canister when setting base timing? I may be wrong, but are you not creating a vacuum leak which causes a rough idle while you are setting base timing. When I disconnect my manifold vacuum advance when doing base timing, I always close off that pipe with a plug or screw to keep a smoother idle for accurate base timing. Then once set, I add the manifold vacuum back onto the canister which adds advance and smooths out idle and slightly increase rpm.
Was also awesome to see you get over 12mpg while pulling a trailer with a charger on it, at speed. I would say that that car runs near perfect.
That’s right you were there and saw it, some people deny that happening
@@junkerup Understandable. I was there and seen with my own eyes and couldn't believe it. lol. Not to mention pulling over hills and I couldn't keep up. Truly was amazing. Could be a pretty cool video to prove it.
What about the "allen headed bolt" inside the vacuum advance for adjustment's. And the different degree mark's on arm and small block & big block difference, I made them there mistake's
Keep doing these tech video’s Chris. Very good stuff
We’re where are you when I had my 68 dodge A108 , 360…. I sold it for $1500 and it drove. Dam……. look forward to watching your channel news subscriber
After watching this video and the last one from yesterday I’m going to do this to all my ford trucks bc I don’t have any mopars and I wana see if can get more fuel mileage on my big block 79
This works on all make and models with adjustable timing and vacuum so definitely give it a try
I have a bone stock '70s slant six with a carter 1bbl. I've had the vac adv plugged into the carbs ported port. The port on my intake manifold had a bolt in it. I found a vac line insert for the manifold and am now running the vac adv there. My question is what do I plug into the ported vac on carb? Right now I just have it capped off.
My buddy had a '66 Chrysler convertible that had a manifold vacuum gauge on the center console (automatic trans). He would race against my '64 Galaxie XL (390 auto trans 1st car). Both would just hunker down when the kickdown engaged and we flew through the blacktop.
What a great video Chris!!😊
Hey chris, first up thankyou for all these videos mate i find them very interesting. I was wondering would this could be applied to a triple weber carb set up. Currently got no vacuum running from the dizzy but still have the module on the side of the dizzy. Thanks mate
Doesn’t matter what carb setup is
@@junkerup alright cool thanks chris, and thanks for getting back to me so quick to. Had to ask cause im still learning 👍👍 i'll let you know how it all goes once im out of hospital and can work on the car again
Excellent video. I learned a lot. Thank you so much.
My 67 Coronet has a wimp 383. Low compression, Low vacuum signal. I run 20 inital and use a FBO lockout plate locked out at 14 degrees. 34 total. I hook up the vacuum can and it detonates it brains out! The last owner had a MP Distributor that made tons of timing. To drive it at 65 mph you had to set base at 6 degrees. I chucked the distributor and bought a reman mom mopar unit. Used FBO plate set to 14 and cranked up intial to 20 , 22 ish. Plug in the can and it`s a train wreck!
I think that anyone who believes "one size fits all" is mistaken.
You have a different issue you need to find
Years ago I bought a '68 Polara 500 with a 383 two barrel. The motor was SO carboned up that it pinged and rattled terribly. After blowing all that carbon out I drove that car for many years. I later added a Mopar electronic ignition conversion, Edelbrock intake, Holley carb, & dual exhaust. It was strong and was never finicky for high octane after cleaning the carbon out. Did you try Seafoam or something similar?
Maybe your carburetor is too lean at part throttle operation(?) Coolant system not full(?)... Make sure to use a coolant RECOVERY bottle to keep system FULL.
Also, if using a stock or very mild cam I would use the ported vacuum source with the 20° initial timing and I would expect it to need more than 34° of total.
Have you ever drilled throttle plates, or seen a reason to?
The valvetrain is pretty quiet. Which specific brand and series lobes are on that camshaft?
Have you ever looked into the progression ignition distributors?
I've often argued that non-emissions engines should run manifold vacuum. That way you're getting ignition advance at both idle AND cruise speeds. Why not have both? What's wrong with having lots of advance at idle? You can thin out the mixture too and have a nice lean, clean idle.
Hey Chris I just wanted to wish you and your whole family a Happy Thanksgiving
If you want to run even more initial timing but experience starter kickback, don't power the ignition until after the starter is already spinning the engine over.
Thank you so much for explaining this and Yes, I learned alot.
Let me know your thoughts on this.
I had a SBC built.
The builder tuned the engine on the dyno and said my engine likes 38* max advanced timing.
Now I don’t remember what he set the base timing at.
But after installing the engine I couldn’t keep the plugs clean when cruising around town.
They would foul out jet black soot and at idle you could hear the engine loading up.
I met another guy that works more with racing engines and he said I didn’t have enough initial/base timing.
So he ran a test on my engine first and then we took my distributor out and he removed the vacuum advance and the mechanical advance and we locked it out at 38* all the time.
I have enough valve over lap to do this with zero cranking issues. Spins right over.
That made such a difference that I can’t keep my tires from spinning. (Smoke show)
After that I took my car to a chassis dyno to see if more timming would help.
From 38* to 40* no HP gain.
Then 38* to 36* I lost around 6hp
So why would I go back to a vacuum advance and a mechanical advance system?
I had a 383 stroker
TH350 transmission
3000 stall
3.73 gears
Engine only on dyno yielded a little over 510hp and 525tq
I am running on 87 octane fuel at 10.2:1 compression.
Idle vacuum in park 15/16
Engine temp 180*
Awesome video great tips. Downloading this for future reference!
If centrifugal advance can not rotate with your pinky ? It need to be cleaned (spring removed)
What outing monder engines in classics
How do you feel about the Rev-N-Nator product that suggests to remove the vacuum advance to perform as it should?
Very, very informative video. Thanks!
Hey Chris thank you for the video and what you're saying there is so very true
I Love your car, General Lee is the coolest car ever!!!! Please don't ever sell it!!!! 😎😁
So can I setup a MSD controller for an LS swap and do the mapping the same way ?
Awesomeness. Many thanks, Chris
Sweet! It’ll be nice when you get the headliner in the general!
Good info! Are you running mech secondary carbs? Is there a reason to run vacuum secondary? I get a lot of "what" and very little "why" or "when" on this issue.
I don’t like vacuum carbs, I want the carb to do what my foot tells it to
My 69 440 New Yorker got around 12mpg on a mechanical Holley 750... without the vacuum advance hooked up. Time to get tuning and do it right. Thanks again.
I have a 318 in a 1985 Ramcharger I bought for a turd project. I dingleballed the cylinders and threw on some rings and bearings, a lumpy cam, timing set, oil pump, warmed over factory heads with bigger SS valves and some self-porting, 4 bbl. intake & carb, headers....all the usual goodies.
Oh, and a Mopar performance distributor with removable/adjustable pods? that limit mech. advance.
It runs best with 22° initial, and my adjustable vacuum advance puts out 13°, so 35° at idle, then I have the mech. advance set at 15°.
I'm getting some ping under load, so I may have to adjust my vacuum and/or pull some mech. out.
But, I totally agree.....manifold vacuum for the vacuum advance for economy, shit & git, and overall drivability.
Previously, I was all about ported vacuum.....I've seen the light!
Good stuff! Thanks!
Chris you guys run 91 octane in Nevada ? With this Cali fuel it’s tough to get cruise tip in without ping with vacuum, I do like the bottom end and idle feel with vacuum, I might try limiting vacuum can.
91, we have same shit gas as Cali now
You buy that place Chris ?
15° static + 15° vacuum + 5° mech (if at all) = 35° at highest vacuum (say 20~30% throttle?!). Seems like a lot way early, but at wot vacuum is zero remaining only static + mechanical = 32~35° max. So total advance has a dip in between the vacuum max and wot. Is that so?
When you go roadtest and get pinging do you remove timing at the distributor or by adjusting the vacuum advance?
Awesome video, thanks Chris
What power valve size you have?
Where did you get that master cylinder? What modern vehicle does it go on?
90 ish Dakota
11.5 to 1, are you running 91 or 93 octane at 1000 feet?
I wish you were in North Carolina
Hey chris , whats the stall on the converter and gear ratio in the rear ?
2600 and 3.23