Part 2 The Ultimate Vacuum Advance Tuning Guide
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- Опубліковано 24 сер 2020
- In this episode I follow up on Part 1 of what I called The Ultimate Vacuum Advance Tuning video... As you can imagine it sparked great debate.. in this video I touch on how to find out what your engine wants for the Vacuum Advance vs what you think it needs... So get your Vacuum Guage, Mighty Vac, and a good friend and you can begin learning how to tame even the most radical street engine..the results will be improved driveability and fuel economy that your friends wont believe is possible!
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This is what I got from the DV video on setting ignition timing.
Idle timing
Mixture first
Connect vacuum gauge to manifold.
Disconnect distributor vacuum advance and plug. (Or connect to vacuum gauge. )
Set throttle screw little higher than normal.
Adjust idle air screws in until engine starts to slight stumble.
Adjust idle screws and throttle screws until vacuum is the most minimal vacuum. This means your engine is idling on the least amount of possible fuel. At this stage you start advancing the ignition until the idle is steady. (adjust ignition timing at the distributor until the idle is steady)
Readjust idle air mixture if necessary.
(Mixture at idle takes precedence over timing. )
Adjust ignition timing until you get the best vacuum reading.
Idle mixture should be around 15 to 16 to 1 fuel air ratio. And advancing or retarding ignition to set at what it runs best at with best vacuum.
Recap;
Adjust idle mixture by leaning it out as much as possible. Consistent with getting the lowest vacuums possible. At this point start adjusting the timing until you get the most vacuum and highest rpm. Repeat until you have the best idle. Then adjust down the idle speed with the idle screw. Continue this procedure until the engine idles like your grandads pocket watch.
At this point you should have a good idea of what the vacuum is at idle.
Check and note timing.
Connect up the vacuum can.
And with vacuum on you set ignition to the same timing setting as noted. Disconnect vacuum advance. And your static advance should be about 15 BTDC or about 5 BTDC. 10 being a good figure. Put the vacuum back on. Open the throttle slowly until the vacuum drops maybe 6 or seven inches and your rpm’s come up to about 200, and see what the timing is. It should be for a typical street cam V8 engine should be about 25 to 30 degrees with the vacuum advance on. Mechanical advance may be about 15 degrees at that point.
As you are going down the highway you want the non load speed at which you are driving you want to have the highest vacuum.
See UnityMotorSports Video by Andy “the ultimate vacuum advance tuning guide”.
There you GO.
Good stuff, Andy! Being drag only, I don’t expect to run vacuum advance on the 73, but I want to do exactly this procedure on my 70 Dart. Thanks for the great info!
Thank you so much OP, I,ve been working on engines like yours most my life and have learned many tips and tricks over the years from people wiser than myself like you. Very much appreciated because like you said they are all different and need fine tuning, this is a great way to do that.
I'm glad you enjoyed it... I plan on digging deeper once Casper is back up and running with MIXED UP BOSS
Thanks for watching
Andy
Its a magical bond between Man and MACHINE
Most cool. I have a hand vacuum pump and all kinds of vacuum gauges and never thought about doing this. This is a huge part of how you dialed in your tune to get such efficiency.
Yeah it's really simple when you break it down... It is time consuming but WELL worth the increase in throttle response and mileage! Thanks for Watching,
Andy
I locked the timing out on my 347 and honestly it did pretty good for fuel economy. It has 11-1 with a 236-243@50 roller cam. I might just try a vacuum advance and see when I get it back together.
Found you through UTG, Tony's awsome, but I'm a Ford guy, and even better I'm a Ford truck guy 👍 My first hot rod was a 79 dentside with a pump gas 460, great truck. Subbed for Casper and the Mixed up Boss!
On my old ford, I used to increase the vacuum advance to max, then road test and reduce the timing advance until it stopped pinging, then a little less. Like half a turn at a time.
Always used manifold vacuum port and adjustable vacuum distributor. Was simple and easy to do with no equipment.
It ran better and got better mileage.
I am looking forward to using your method to compare the difference between the two methods.
Nope, you are right having a well tuned vacuum advance will run better and give better fuel economy! With the new setup it will be interesting to see what I can do with it
Andy
@@UnityMotorSportsGarage
Could you explain what you did with the numbers you wrote down while driving?
Let's say I find a long flat stretch of highway and I cruise it at 65 mph.
I note down my mph/rpm, vacuum reading, and how much vacuum the MityVac applied.
Ok I come home, grab my Mallory chart and try to recreate what I did while cruising.
Let's say I find I need to add 10 degrees. Your Mallory chart says that requires about 6 turns.
Is that It? Just add turns and I'm done? I feel I'm missing something because I'm ignoring the inches of vacuum at the bottom of the chart.
Straighten me out please.
Maybe I'm confused also because the chart I have for my adjustable vacuum pod shows to screw it in all the way for max advance and each turn out decreases advance.
Edit:
Also....
I have a huge hill that kills me on the incline. Would I benefit me to do what you did here but do it as I climb that hill or is that simply a function of mechanical advance and secondaries tuning?
You ask some great questions. I found this video frustrating to watch because I could tell he has a good technique that he wants to share, which is clearly worthwhile to pursue, but he just can’t seem to explain the steps clearly.
Thanks Andy another video full of relevant and descriptive facts.
This video was full of information that is so useful,andy you know I’m a fuel injection guy but my buddy has a SB 400 Chevy that is very close to the setup you have/had on Casper I can’t wait to try this and I will let ya know how we make out because the weak point of his set up is driveability. Thanks for another great video.
Thanks for watching.
Manifold vacuum only! Get initial, mechanical advance and total timing properly set. Then start working on vacuum advance. Run all you can without detonation! Set the rate as aggressive as you can without detonation! Detonation testing is best done under engine load if you can find a good hill to climb....
You can tune out a lot of your cam lope with a lot of vacuum advance!!! Smoother idle for that sleeper sound! 😂
Good info! Your doing a great job of filling the blanks left buy other channels. Appreciate it very much! Keep on!
Thanks for Watching Connie!
This is a super cool video....if you want to run on the street you got to know what your particular combo needs and vacuum advance is the way to go if you want any kind of MPG.... Plus you get drivablity as a bonus and clean plugs.
So true!
Something you should also note on your next video is some adjustable vacuum cans adjust rate at which the advance comes in and then there are the cans that adjust the total amount of time the vacuum advance will add. Mine was the rate and gave 20° advance no matter how much I adjusted it. So may be something you want to let your viewers know. Once again great video.
Yeah I've talked about how some cans have a fixed rate and others have an adjustable rate... I would say that 90% of all aftermarket distributors today have a fixed can which is WRONG.... There is a company who now offers what I consider is a ingenious distributor... Progression ignition which is full programmable but in the "mechanical advance and vacuum advance" and can be adjusted on the fly via bluetooth from your phone! I really want to try one..
Andy
Would have loved to have seen your afr,s as you did this after watching your stuff on idle/ transition circuit mods, top stuff.
Awesome video, sir! So this can be done when the weather changes as well I’m sure as part of a tuning seasonal… very cool! I am following you Rock the tune!
I thank you and David for the invaluable information. If I remember correctly my friend Ken Shawver that ran stock elimtor and super stock ran a vacuum advance. I think he said it "cleaned up the idle "especially handy when going to the staging lanes. He also phased in the rotor. Another video? I watched other car going to the staging lanes a most of them would run rough and sometimes stall. And maybe even start some plug fouling? I found out the importance of vaccum advance from Davis books and helped me our alot on tuning small block chevys. I got alot of stories about but sometime later.
The value of vacuum advance is far too understated.. you get a cooler running engine, better low speed drivability, better fuel mileage... Plus the engine is just happier by having the right amount of timing lead...
Thanks for Watching Don!
Andy
How do you "phase in a rotor"???
I have experimented with this but you just gave me a whole lot of methods to use to try to tune in my vac advance. My 74 Bronco with a slightly modified 302 burned out its last Ford electronic ign module, I'm done with Dura Spark! I swapped in a original 289HiPo dual point and it runs great under hard acceleration but lost "normal" driving manners, I want the low speed smoothness back and will be swapping a vac advance distributor back in.
Yeah a distributor with a vacuum advance is a must for drivability and mileage! Thanks for Watching
Andy
A few years ago now I asked a question on a forum about tuning by vacuum and if would increase mpg. The forum is very well known but is EFI related. I received 1 answer which was "it wont have any effect". I've been pottering away testing this on my own and have come to the conclusion your videos tell us. If we want performance and good mpg we must give the engine what is needs/wants otherwise we are short changing ourselves.
You are correct! the engine must see the proper timing curves to be happy! People dismiss the vacuum advance distributor because they see folks running Mechanical adv. distributors on the track... If you drive the car any on the street you are short changing yourself a great deal... having a properly setup Vacuum advance will give you increased throttle response in the tip in... and it will give you a nice gain in mileage! Thanks for watching and please subscribe as I have more good stuff coming!
Andy
It makes no difference with efi because efi doesn't need a vacuum signal to adjust a carburetor mixture......2 different animals.
It depends on the type of Fuel injection is being used .. if it has a Map sensor it uses vacuum to reference
@@PTucker0864 Using GM Delco Memcal based ECMs/PCMs I can tell you from personal experience it does make a difference. MAP or MAF it doesn't matter. Timing to achieve the optimum Manifold Air Pressure or Mass Air Flow before you get detonation will get you the best economy.
Thanks a lot Andy!! Great knowledge
Thanks Mike!
Andy
Well hell, now I don't know what my motor wants and I don't know what I want, we need a part three in detail
Sounds like a you problem :/
Hey Andy I’m just binge watching some older vidjas. Great vidja 🤙🏼
I gotcha Dylan! Thanks again brother
Andy
Im going to apply this to my 79 granada with a 250ci 6 along with changing the mechanical advance spring/s to see what it likes a 2bbl will come at a later date. Im running the original duraspark 2
We were doing this Saturday morning after watching your videos. But the car seemed to be quickly loosing power and we had a lifter tapping.
Took it apart and found a lifter not pumped up and the cam is starting to round off. The Competition Cam lifters and camshaft only have around 1,000 miles on them. We have used Royal Purple oil with zink as a break in oil and then their normal zink oil ever since.
We are going to throw a new lifter in it so we can take it to the second and last car show this weekend.
So you are not alone in engines going bad.
It looks as though it might have been only a bad lifter. He put another lifter in and it seems fine. The lifter still spins while it’s running. Will have to see how long it lasts.
Andy this is what I need! I knew this is what the old guys did back before electronics and dynos... but I've never been able to tune properly with a vacuum gauge as you did.
Some numb nuts lost my factory distributor and they installed a cheapo fancy HEI. They said it would be better and I argued the weights and vacuum advance diaphragm aren't tuned to my truck. It's never been right ever since.
1981 GMC c3500
350
Th400
14 bolt with 4.56:1
100% stock except a hydraulic liftgate. She's a heavy GVW so no feedback carb, ecm, cats, nor O2 sensors. All factory built.
She's always loaded heavy and she's my backup tow vehicle. I can get 13-15 MPG on a 200 mile round trip loaded with maybe 1000 lbs of shtuff in the back but she's way down on power and hill climb performance.
Could you explain a little further your chart/table you wrote ?
Great video and explanation.
Thank you!
Hello, Great Video, that as a novice, I really want to understand. 1) Say you’re cruising at 3,500 RPM and the engine is making 15” of vacuum, so you keep adding hand pump vacuum until the engine does what, sounds stronger, picks up? 2) So once you know the vacuum it wants at a particular RPM, how to you set that / replicate it in your driveway ? I’m slow, thank you for your time, best, JR (any chance of a video where you take a car not running good and go through the whole procedure beginning to end?)
Thank you for your insitghts and video 🙂❤👍 PS: Thats a strong motor
Thanks for the kind words, Jimmy.. that 393w was a hoss... I hate it that it died.. but I believe the new setup with MIXED UP BOSS will more than make up for it! LOL
Andy
Not sure what to do after you stated to note the timing compared to the vacuum you recorded? My 460 initial timing is at 15, Mechanical brings it to around 24, but when adding in the vacuum advance, it jumps to around 58, @ 3000RPM. This is timed port and no pinging and the engine really likes it. If I use the manifold vacuum, it does not seem to like it as much, mid RPM, starts to shake a bit. I tried to set the vacuum canister back all the way, counter clock wise and it made no difference. Any suggestions? Is this a bad vacuum pod? I was told, if the engine likes it where it is, leave it. Fuel economy seems good so far, will know more on that in the coming days. Thanks for the great videos!!
I would say the same goes for locking up the centrifugal advance. If you don't have the centrifugal advance working properly you are giving up lots of power and economy across the power band as well.
Can you do a 3rd video showing the final steps? Once I get needed vacuum on the gauges, how does that cross over to setting degrees of timing? Thanks
This was really helpful
👍🔔😎
Very good.
There are/were vacuum cans that start to love at different vacuum levels
There are cans that have different total amounts of degrees advance.
The old Ford units of the 60s-70s had a hex outside the vacuum hose, and that hex unscrewed. Inside is a coil spring that resists vacuum. You can change the springs or put a washer shim under the spring to make it tighter.
Some cans had the allen wrench adjustment to set the maximum degrees advance.
Those Ford units converted to electronic distributors are excellent.
JMO.
Thanks HRR 😎😎😎
Not LOVE but MOVE, LOL.
Spell good, just cant type worth a nickel. 😁😁
Hooking manifold vacuum not ported vacuum and getting @ 15* at idle helps smooth out those lumpy cams and makes throttle snappier.
Will the vacuum be affected by the gear selection? Should my manual transmission be in 4th gear or 5th gear overdrive? Or does it make a difference? Your help would be appreciated
It is this simple , I worked for a speed shop when I was a teenager , my boss was a very knowledgeable guy. He always told me the vacuum advance always went to what he called progressive vacuum . So say your leaving a red light as you give your car gas it advances the timing. If you plug your vacuum line in and at idle and your timing advances its wrong.
So you have the cannister hooked up to manifold vacuum? Thanks for posting.
Caspar! What happened with the motor? You should be able to smoke a cigarette,drink a soda, eat a big-mac, text Uncle Tony, and call mom while doing this.ANDY ROCKS🤪🚙🔥🔥🔥💨💨💨
If my 1949 Chevy sty line Deluxe with. New? Engine. New distributor rebuild carborator is hesitating on 1st 2nd and 3rd gear would it be? My vacuum advance any advice would help thanks
I didn't use the road test method a couple of years ago. I just limited the max the can added to 10*, reduced the initial to 4* for starters, on start timing jumps to 14* to 16*, and it idles smoothly even when cold. The engine vacuum jumped up to 20 to 21 inches in park, and at 65 cruise, engine vacuum is 16 to 17. This stuff really works well. I never considered using this with something like a tunnel ram. I guess this will work on a healthy single plane as well. Well Now.
say my advance is all in at 3000 rpm but my cruising rpm is between 2000 and 25000rpm what do i have to do to get the perfect vacuum advance for this cruising rpm?
great fan shroud!
Just checking in and hope Casper's new engine is being built as you planned. I know it takes a lot to do video work when building something then edit all the video.
At the risk of showing my ignorance, I have a question or two. I liked and understood the method you were using to obtain the information for the engine to tell you what it wants to choose it's vacuum canister settings, but I decided to go one step backwards and consider how the centrifigal advance gets optimized before that. After watching a number of videos and some reading, the general info seems to be 'mechanical advance all in by 3000 rpm' for a performance engine. That seems far too generalized in light of the train-of-thought to let the motor say what it wants. I was wondering if tuning the mechanical advance (before tuning vacuum advance) could use a similar approach... do not let the mechanical advance weights swing out as rpm's increase, but use a mity-vac on a vacuum canister to advance the timing for rpm's from say 1000 to 3000 rpm finding the optimized advance setting needed at different points in the 1000-3000 rpm range. Maybe all in is before 3000 rpm, or slightly higher. I welcome information if there is a blindspot in my mechanical advance understanding... THANKS FOR THE VID!
Great videos!! I wish you would show one with a Progression Ignition distributor. You can really dial it in those new units.
Yeah when I get MIXED UP BOSS in CASPER that is on the to do list!
Thanks for Watching
Andy
I agree. Progression is awesome. Unfortunately the company has minimal tuning info.
Andy, great video! Curious if you have used this same method of seeing what you engine wants while using the Progression Ignition distributor?
Hi..i just came across your video when searching for how i can achieve better mpg from my bbc 396. I just bought the car and mpg are horrible. I upgraded to a 4l80e and i believe it has 3.07 gears in rear. I do have a petronix distributor w vac adv. I dont have great mechanical knowledge but i did follow along with your video to an extent but couldnt understand how i as a novive can tune my car for better results. With pulling manifold vac instead of ported in and bu itself producevbetter mpg and performance or do i need to fully tune for best results? I would appreciate any help or opinion. Thanks
sound good my brother
I'm so damn confused, Is there a part three that will make sense of this video, what do you do with the numbers you get
You need to tailor a vacuum canister that replicates those vacuum readings for YOUR engine. Different vacuum canisters have different vacuum requirements for advance produced, based on part number and original application.
I totally agree with you. I feel like I just sat in a automotive biology course covering the timing of the heart. Great info. Now I'm being expected to go do heart surgery not not even a lab to show me how to do it. What in the world does the note pad RPM, engine vacuum reading and the readings on the mighty vac relate to how many turns you need to put into the vacuum pod?
Thanks for asking that. I've watched this video oh say 20 times in the last week lol and trying to grab hold of the what exactly to do afterwards. If I can pump in 20 inches of vacuum at 3200 rpm while I'm driving and the engine is responding well that's great!
Then I get back and wind the motor up to 3200 in the garage and then pump that same 20 inches into the va canister and see how many degrees im at on the balancer great again but THEN WHAT ?? LOL
@@life_of_riley88 won't an adjustable canster do the same thing?
Having an adjustable canister is the key to it all...it's not about what you think your engine wants... It's about giving the engine what it wants to be happy!
Can you give us the best order of tuning? Obviously initial Timing first but then Total Timing then adjust vacuum advance or…🤷♂️
Excellent, Thank You
Glad you liked it!
Be interested to see if doing this with a tbi like a sniper would make a nice mpg increase
Hi, were you connect the vaccum hose, thanks!
How does this relate to Base/Initial timing?
Good stuff, thx!
So your dizzy hooked to port or manifold vac?
I like the Finnigan's Speed & Marine hat.
Thank you 👍 👌
I have a DUI distributor that i had them build for me with all of the specs they require upon purchase (vehicle weight, rear gear, cam,cubic inch, converter stall etc etc) I'd have to go dig for the build sheet, but im pretty sure it was 23 degrees of mechanical advance and 12 degrees intial, putting me in the 34-36 sbc range..... now my question is, they never really talked about the advance canister and what kind of advance it pulls at a given amount of vacuum.... the advance canister is smooth and round so im guessing it isn't adjustable?? i wonder if a guy emailed/called DUI if they could shed any light on my question
Yes they should be able to tell you the specs on the canister! Thanks for Watching
Andy
Hi could you please make a follow up video on how you set the vacuum advance at each rpm settings you documented in just lost on how you make these setting at the different rpm ranges
As soon as I get CASPER back on the road with MIXED UP BOSS I plan on continuing this.. Thanks for Watching
Andy
@@UnityMotorSportsGarage that would be great can't wait
@unityMotorsportsgarage I’m attempting to set up a basically stock 460 Ford Duraspark 2. If my idle advance is at 12°, virtually all of it is coming from the vacuum advance, meaning my base mechanical advance is virtually 0. I believe this is causing, a part throttle hesitation due to the lack of total advance. Conventional wisdom, would say move to port vacuum, raise the base timing for idle. However, I’m sold on your (David’s) theory on tuning. So do I’ve leave it at 0° and tear into the distributor to get more mechanical advance?
You need to have the mechanical advance setup for your combo before you do the vacuum advance tuning..
Thanks for watching
Andy
Since Casper is down you should have Dave Vizard do the video of the actual process once you have your numbers and you are back under the hood. That way we can see how to do it. Most mechanical guys are more visual learners. :) Do you need to get a different vacuum canister if you have an adjustable one? Great Video look forward to the final video.
Yeah you will get to see the CASPER's transformation once we get the engine Dyno numbers to having it in the truck and the RWHP from the Chassis dyno to us running it at the track... The icing will be seeing how drivable we can make it! I have some cool tricks up my sleeve! Thanks for Watching Nathan please Subscribe and follow along...
Andy
I also want to know if you need a different canister if you already have an adjustable one.
I'm struggling with this right now. Not perfect, but in the ballpark I think, Since my 400 hp Chevy small block in my 34 Roadster hot rod get a 25 mpg mileage on highway cruising. Probably much thank's to the 0.5 overdrive on 6th gear as well!
Hey Andy: I'm a big fan of the channel, you, and David. Question: How do you replicate this process with the new Progression Ignition dizzy? I have had mine installed about a year and love it but interested in fine tuning the advance curve w/o a dyno?
I'm getting ready to do some videos on that! With this system it makes it very easy
Andy
Hey Andy. I'm currently running my PCV setup utilizing the manifold vacuum ports on both carbs. Do you believe I'd be okay running the PCV off of only one carburetor, so that I'd be able to use the other port/carb to run a vacuum advance? Thank you!
Yeah that will be fine!
Andy
What's happening under the hood as you're cruising down the highway? Around 7:18, it looks like something is burning or glowing in the engine bay on the passenger side. You got gremlins under there smoking?
It's just the hood light... The mercury switch was acting up...
Andy
What size Allen wrench
I ran into this very issue with a 253@.050 cam in a street motor. The motor wanted tons of advance at idle, but was wayyy too much to actually drive with. Ended up using vacuum advance to give it a ton of advance at idle, that drops off right away when you punch the throttle. Perfect solution that was being used as long as engines have been made.
My respect for David and you on this valuable information! but have you thought of trying a ‘Progression Ignition’ instead? Controlled electronically and tuned on your phone or tablet and it doesn’t rely on vacuum or weights.! just a thought....
It funny you say that... Once I have project MIXED UP BOSS in the truck im planning on trying the Progression Ignition and I would like to do a back to back test with it.. I think it has A TON of potential! Thanks for watching,
Andy
@@UnityMotorSportsGarage I don't know the Progression Ignition and how it works, but it surely should take vacuum as a measurement of load into consideration. I have experience with Megajolt where load is defined either by vacuum or a TPS. Nodiz is a more advanced system leaving out the need for a Ford Edis module. On both systems you can build up the advance curve after your own requirements with extra adjustment options available. Best start is to emulate the advance curves (with closed throttle and wot as upper and lower limits) and then experiment. Looking at the routine you went through with writing down the various underpressures you measured while driving, how do you think to apply this on your engine while being stationary? When you rev the engine without load it revs higher on a leaner mixture than while driving, so you end up with a mismatch. Am I missing something in your line of thinking?
Soooo, we can just plug the “ported” vacuum port off the carb and just use the intake manifold vacuum ? Correct... ???? And with a adjustable vacuum advance tune it in.... 🤔👍
That is it!
Andy
Informative & thanks for sharing this. The only comment I would add - and maybe you covered this in another video is get your mechanical advance sorted out first, then work on your vacuum advance. I have been doing essentially what you cover in this video on every car I have owned going back..... 45 years! And it is well worth the effort.
Thanks again.
Yes sir you are correct the Mechanical advance is a whole other animal! That would be a good topic to cover as well... Thanks for Watching and please Subscribe as I have more to come!
Andy
Yeah.....I’m a little new to this,so what is your idle timing with the vacuum hooked up and at what rpm is your total mechanical timing all in?
Just curious because I have a mechanical distributor with idle timing at 26 deg. advance and all mechanical timing in at 3200rpm at 36 deg. I too am running a tunnel ram on a 327 Chev.
My vacuum reading at idle is 6.5 at 850 rpm.
That idle vacuum seems really low... How big is the cam in that 327? On my 393w I had my base timing at 16 degs.. I use Full manifold vacuum and at idle I seen over 30degs ( it could use more ) but you are limited to the Vacuum can on the distributor.. my total advance is 30 degs all in by 3000rpm... By having more timing in at idle it will run smoother and cooler!
My guess is your carbs are really fat at idle to have that low of vacuum... Normally if it is a huge cam you will have a much higher idle than 850rpm.. Thanks for Watching Don
Andy
@@UnityMotorSportsGarage
I don’t know the specs for the cam,but it’s pretty choppy and it’s a good runner too.
But I only street it so that’s why I’m now looking at trying some stuff with a vacuum advance distributor.
478 hp as is.
@@UnityMotorSportsGarage hello Andy my name is al man . I've been pounding this stuff into my head for the last week and getting everything needed for the set up . Seems like the best all around info I've seen and I'm a huge Vizard fan as well although sometimes his awesomeness flys right over my head lol so a guy like you is helpful to me .
What exactly do I do to lock in the scenario I get in the vehicle with the pump and vac gauge and tach ?
.say for instance I'm 20 vacuum @ 3200 rpm in the car then I get bsck and park it and hook the pump up and feed the canister that same 20 inches at 3200 and I check my timing at that point and its say 30 degrees.....then what??
That's the part I'm not picturing/understanding
@@aml3961 At 9:42 Andy shows a graph (specific to his Mallory canister) which plots timing, vacuum and turns of the canister. After you get the timing degrees for each of your points, you have the info you need to compare to the graph and determine how many turns of the canister would most closely match the curve you made from your tests. I suppose you’d have to create your own graph with a your vacuum pump and timing light. You’d then just average out the three points to settle on the number of turns which is most suitable.
Hey mate , what if adding vacuum advance doesn’t increase my engine vacuum ? My can allows 20 degrees of vac advance but doesn’t seem to make a difference when I pump it in while cruising..
Bad canister?
Nobody EVERY explained this !
Or turned their car into a rolling road Dyno for SO LITTLE MONEY
I thank you .
Thanks for Watching, David Vizard tought me over the years all of these little tricks... I want to pass along what was freely given to me! Please Subscribe as I have some really good content on the way with MIXED UP BOSS...
Andy
So you're running manifold vacuum and not ported vacuum???
Do you have trouble with hot starts with your timing at 40 to 50 with it kicking back on the starter or with it pinging under a load accelerating??
I'm going to have to go back and watch video 1 & 2 again lol
No, because the engine will not produce vacuum until it's running then the timing will advance.. the key is having the vacuum pot dialed in... When you are under a load the vacuum drops and pulls timing so it stays out of detonation..
Thanks for Watching
@@UnityMotorSportsGarage
Do you tune your mechanical advance as well?
Oh yes... You need to have that dialed in before you dive into the Vacuum advance.. once I get my new setup running I plan on doing a more deep dive Into this!
Andy
Great videos Andy! At 10:55 in this video, did you mean for the caption to say ‘16 mpg around town’? Or the other way around? Or maybe not, with 4.30 gears on the highway, 12.5 mpg would still be good! lol
Yes it would get the 16mpg around town... Even loaded down with about an extra 1000lbs on the trip to Tennessee doing up into the NC mountains I got 12.5 mpg on the interstate at 70 mph...
@@UnityMotorSportsGarage You should be able to do better on the highway with the proper vacuum advance. That's where you want your advance the most, is at cruising throttle, when your mixture is lean, and coming off idle.
@@andy16666 deep gear gonna kill your highway mileage no matter what. Need OD to get any MPG out there.
@@thereluctantgearhead4544 that, and the lack of a torque converter clutch.
@@andy16666 yep, non lockup converter definitely burn more fuel too.
First, thanks for the info on the vacuum advance setup! Subbed!
Q1: In part 1 you mentioned a company that makes custom vacuum advance units. Who are they?
Q2: _How do I sort out the mechanical advance?_ It's been mentioned in comments for both of these videos to get the mechanical advance sorted out first. Given the objectives of the Vacuum side you just covered, how do I figure out how to set up the mechanical advance? I know how to open it up and change it, but not _how_ it should be changed.
BACKSTORY:
I've been struggling to get decent mileage out of my 48 Willys CJ daily driver. It's got the wrong carb, but it's the only one I have. More on that in a minute.
The engine is a 67 Dauntless V6.
From the top down, it's got a 650 Edelbrock sitting on top of an Offenhauser Dual-Port* with a Comp Cams sub .5" lift torque cam. The motor is stock bore & stroke breathing out a hand-fabbed 'dual-Y' headers I 'mathed out' to be as correct as I know how for tubing dimensions and lengths.
Between the stock 5.38 gears, 32" tires, and no overdrive, top speed is about 65mph at ~3650rpm. I rarely (like once a year) get into the secondaries so I don't worry much about the carb being 'too big' for a 225. Yeah, I could swap back to the stock 1bbl and intake, but the dinky primary runners on the Offy manifold give great torque and throttle response.
Ignition is an unknown brand aftermarket HEI for an oddfire motor. I'm mixed on whether I like it or not. The computer (stock type) has shit itself twice now. The last time I was 90 miles from the nearest parts store out in the back-country of Idaho with no cell signal...
Current mileage is between 7 and the rare 10 depending on how much gear I have loaded and whether or not the top is on. For a 2600 pound truck this is kinda bad.
* Think of it as a single-plane manifold that has been split in two - the top third of the runners are a single plane fed from the primaries. The bottom two-thirds are a single plane fed by the secondaries.
The name of the Company is Performance Distributors
hope this helps.
Andy
@@UnityMotorSportsGarage Sweet! thanks a lot!
I set my vacuum advance i bit different. I set my throttle to form a sqare at the t slot. The i set the mix screws and flote hight. Then i adjust the timing with vacuum advance not conected for max stable vacuum then back the timing to drop the vacuum 1/2 hg. Then i take a timing reading and say it is 21* , and say the centrifical advance is 24* and i know that best take off happens at 6* of base timing .then the totel is 30* vary normal so then i know that 6* on the static timing is ok then i take 21* as that is best for idle so 21-6 =15* of vacuum advance. It works good for me! Keep us posted on the progress!
I may try this method. I’m in the process of doing a proper tune on my 440 GTX. Ive always heard that a square at the transfer slot is the desired setting. Doing this as a first step makes sense to me. This way you can be assured that the idle circuit is actually functioning through the mixture screws as it’s designed. Sounds good in theory at least. So long as the idle can be dialed in at the highest vacuum reading with the mixture screws at say 21• like your example. The recommended total timing for my application is 36-38 degrees (according to cam manufacturer) as well as Mopar Performance tuning guidelines. Hmm lots to think about
@@mikeberry2135 the 21* degrees i was referencing was best idle timing determined by max vacuum - 1/2 hg as a example. around 20* is normal for a stock to mild cam for best idle timing. so if total timing is best at 36-38 it is best to shoot for 25-30* on the street as you will have more tork at peak tork over a wide range. 36-38* gives best hp but less tq and is on the edge of pinging. so if 21* is best idle and typical vacuum advance pulls in 14-15* . best idle timing =21*-14*= 7* for base timing. for a total timing of say 28* -7*=21* degrees of mechanical advance. a timing curve of 7* for base ,21* for mechanical, 14* for vacuum advance is a vary typical. so 7*+21*=28* total at 3500 rpm . a good starting point for having total timing in is 3500 rpm. if the idle timing if was say 21* based on the test i gave was best, you would use 7* degrees for base timing and 14* for vacuum advance as that =21*. the rule of thumb is a total advance of 25-30* for street total timing. so the typical static timing will be vary based on how much is in the mechanical advance. so for a total of say 26* with 20* mechanical you would use 6* degrees base timing. say best idle is at 18* based on vacuum and square t slot is 18*-6= 12* vacuum advance. the rule of thumb is 20* in the mechanical advance, 10-15* in the vacuum advance and 5-10*in the base timing for the street. hope this is of help. hope you get the 440 GTX running good! if you need help i am willing to give tips.
After watching this, part 1 makes way more sense.
Thanks for Watching! Hope it all makes sense... When I get MIXED UP BOSS in CASPER I want to continue the series
Andy
I'm confused I have a vacuum advance and people tell me it connects to the carb.. your saying the manifold?
Many (most?) carbs nowadays will have two useful vacuum ports: one above the throttle plates (ported or timed vacuum), and another below the throttle plated (manifold vacuum). The phrase 'manifold vacuum' doesn't necessarily mean the connection is 'on' the intake, but rather the vacuum available at that port = manifold vacuum, as it will if that particular port on the carb is below the throttle plates.
So...two ports on newer carbs. One gets used, the other gets blocked off. 'Course, on 50's and 60's cars (up to about '69 or so), there was only one vacuum port, and it connected to a hole in the throttle body 'under' the throttle plates, thus supplying full manifold vacuum to the distributor. Ported vacuum showed up around '68 or '69 as a way to reduce emissions. Lots of advance as idle and low engine speeds and under light loads means a cooler running engine, but lots of NOx emissions. Ported vacuum reduces advance at idle and low engine speeds under light load and reduces NOx emissions, but makes for a hotter running engine if you're idling or sitting in traffic a lot.
You never mentioned which port you use after you've adjusted the advance pod is it ported vacuum or manifold vacuum 🤔
He uses full manifold vacuum. Him and David Vizard discuss that in part 1, it’s a really good watch if you haven’t seen it...
Does it hold pressure. Or you have to keep pumping the hand pump.. thanks
It holds the vacuum.
Thanks for watching
Andy
@@UnityMotorSportsGarage umph. Mine loses the pressure I gotta keep pumping on it.. thanks
Where would you start with the initial mechanical timing before one begins to set the vacuum timing?
I would start around 15-18 degs.. It all depends on your cam and compression ratio but this should be in the ballpark. I would get the Mechical advance curve dialed in then work on the vacuum advance curve... Hope this helps
Andy
@@UnityMotorSportsGarage I might give it a try, but I will need to get another vacuum pot since my current one provides 18 degrees of vacuum advance. If I use it with a 15 degree initial setting I will get 58 degrees of full advance at 2500 rpm. That might be too much. That is why I presently have my initial timing set at only 7 degrees adv. Thanks for the info.
@@darylw792 its not a different vacuum advance you need . You need a limiter plate in the distributor to limit the ammount of vacuum advance
@@aml3961 That is a possibility. An adjustable vacuum can is another.
Are you guys still running any mechanical advance?? Or is it locked down and using all vacuum? Do you have a ballpark rule of thumb regarding that?
Yes we still use the mechanical advance and once you get the curve set for what the engine/car combo likes then you can move to tuning the vacuum advance
Andy
@Unity MotorSports Garage so get what I can out of it curving the mechanical with vacuum hooked up or not hooked up?? And then fine tune the vacuum? It's a pertronix flame thrower III that has both and I believe the vacuum is adjustable.
When I hook up my vacuum advance it starts pings through the exhaust why is this happening. Never used to do it with hook up to port vacuum then I got new AFR heads machine shop built the motor and and I installed it and took it for a ride it was ping like crazy. So I unhooked the vacuum and it stopped. But now it doesn't really perform like the last engine I have and I have a lot better heads. I have a msd hei in it and was thinking I need a msd vacuum advance stop plate install. Will this help my engine run like it used to. This is a 383 Chevy AFR 195cc all forged Eagle bottom eagle bottom end quick fuel 735cfm vacuum secondary carburetor... Please help
Oh yea I got my initial timing at 12 and total timing was 34 at 4,000 rpm
So the stop plate has A B C D on it. so far I start with it at A what says in the directions 17-11 was still pinging but not as bad. So I put it on B and it was pinging less. So tomorrow I will try C see if that works. Please help am I even doing this right 😢😢😢
What distributor are you using?
@@UnityMotorSportsGarage I got the msd street fire hei. Gonna upgrade soon as I get the cash saved up. So last night I put the stop plate on D which is the least amount of vacuum advance and it's still detonating while cruising.so I unhooked it and plugged it and bought the MSD advance curb kit for that distributor had at local parts store put one lighter spring on it and man it made a difference I put the total timing now at 36
@@UnityMotorSportsGarage with the lighter spring now the mechanical Advance comes in a lot quicker I would say like 2,000 RPM I put 36 total timing and it runs way better with one lighter spring and one stiffer Springs. Should I tried both lighter Springs and see how it runs or just leave it???
thank you andy
Thanks for watching
Andy
Ok, so I have watched number 1 and 2 of these videos half dozen times trying to follow this theory.. I don't know if I am the only one having a hard time figuring out this process or not but I am having extreme difficulty trying to understand how to execute this procedure.
I understand that point of hooking the vac and gauge up and say getting to 2500 RPM and recording the reading of the gauge and the vac but I am completely lost at how to figure the numbers to get the timing.. I am a auto body and paint guy and can restore the body of your truck like it's no thing.. but when it comes to the engine tuning I am lost and it's difficult to understand some of this video.. basically once I get the recordings of the gauge I am completely lost to that point
I completely agree with you. The video does not clearly explain step by step what to do…….so you are not the only one confused
Yes, vacuum advance is vital for fuel economy and driveabilty. That is absolutely true.
And yes, it´s also true that the engine might have other needs than you think it has.
But it should be ported, not manifold vacuum.
The reason for that is as follows:
A ported vacuum advance will have the EXACT same ignition curve except when idling so you will get the same driveability and fuel economy, except if you spend a lot of time driving at idle only, which most of us doesn´t.
And manifold vacuum will mean that a split second after the starter engages the engine will see almost full ignition advance which is very tough for the starter motor.
Let´s say you have 10 degrees BTDC and 15 degrees of vacuum advance, that engine will have 10 degrees of advance when the starter motor begins turning the engine around but after half a turn on the crank shaft it will have let´s say 20 degrees of ignition and after another half turn it will have 25 degrees which can mean hitting the starter motor with some serious kickbacks. I heard that just a few days ago on a bigger engine.
If you run ported vaccum the starter motor will never see antyhing more than 10 degrees which means very low risk of kickbacks. Even if you pump the throttle while starting it will have about 10 degrees of ignition since the throttle plates get the vacuum back to atmospheric pressure every time you pump that go-fast pedal. And 10 degrees is MUCH easier on the starter motor than 25 degrees.
With the engine running, as fast as you open the throttle even a very small amount the ported vacuum will open to send vacuum to the distributor, saving fuel and increasing the driveability.
The manifold vacuum should be used for vacuum modulators on transmissions, Corvette frogeyes, brake boosters (bigger concection) etc.
I´m apologise for the language if needed, if you misunderstand that is because English isn´t my first language.
So is there a part 3?You kind of left everyone hanging
It will come... When Casper kicked the #7 Connecting rod out it put me in high gear on Project MIXED UP BOSS... So once it's up and running I will finish part 3... It will be fun seeing just how drivable I can make a 750hp NA combo on the street...
Thanks for Watching please Subscribe and help me spread the word about the channel!
Andy
Awesome
Hey Andy,I've been out of commission. Still would love to see your technique applied to the distributor that I have. That is progressive ignition. You can tune with a cellphone.
I plan on investing in one of those units to test! It can take things to a whole new level.. in my opinion. Hope all is well your way
Andy
@@UnityMotorSportsGarage thanks. I'll be watching.
A cell phone...SAY WHAT?
@@mikef-gi2dg yup.adjust timing without even opening the hood.
@@randisellingham2551 What? Get out of here!
Shut the front door. Where do I find out more?
Wouldnt a chassis dyno be great for this? I had a engine once, i ran out of money, and had to run a modified computer controlled distributor, with no advance, it had near 13:1, and trying to run it on 93 octane, it got about 10 gallons to the mile, I had it rich, trying to fight detonation, i was young and dumb, it sounded great, 355cid, 285° 507" lunati cam, 750 holley, i put $150 in gas cruising town one weekend, and that's when 93, was under $1.79/gal. Over 20years ago,
I did get some av gas once, that made night and day difference, i could give it more timing, i bet it gained atleast 50-60 HP, and a good bit if TQ! It smelled good too! Just like race gas, it was about $2.25/gal,, a decent distributor and more octane, it would been great!
Like most questions... It depends on the type of chassis Dyno.. if you were to use an inertia Dyno the results wouldn't be accurate but of not having a load... But Eddy current Dyno's can be loaded to simulate the vehicle being driven down the road.. That would be the absolute best way to arrive at these numbers!
Thanks for Watching!
Andy
It's true I ran mainflod vac engine ran cooler and better performance than ported vacuum I do have have other concerns 351 Windsor .
Is this old footage or did you get casper going again?
This was shot before the epic fail. Stay tuned for the resurrection.
@@UnityMotorSportsGarage I can't wait, good luck with the build!
When you're on the highway, why's it look like there's flames under the hood?;
its the under hood light..
Andy
That exit you got off on.
Was it close to a restaurant Hillbilly's?
I'm about 99% sure I know where your at.
Yeah that is the McAdenville exit. That is where we used to live!
Andy
@@UnityMotorSportsGarage dang! . I was hoping you was there. Mcadenville is in the back yard.. I been here all my life ..
You anit still close are you ? , I got a 82 c20 305 pretty sure its stock i bought it from a teenager and I'm sure it could use a seasoned mechanic..runs great though .id like you to tune it you seem to know whats what. I don't mind paying for your time I know time is money. .
Great video by the way its well informed I don't have the gauges or experience to do what you did here.
Thanks for all you've done its greatly appreciated.
I wish I had seen this before I installed my new MSD no vac advance distributor .
Im kinda dumb, what does the timing have to do with setting,,, is that just for future adjustments of resetting timing or ,,do you move the timing,,kinda fuzzy area,,,,can you not just adjust the vacuum pod to the difference in the vacuum the truck liked at that rpm,, I must be missing something,,, like I said I’m kinda dumb
Can’t you just pull the vacuum pod off ,,,adjust it down to be all in at your desired vacuum with the set screw,,,,and reinstall,,,
Say it takes 20 to pull advance full and your motor only pulls 17 at desired rpm so just set the pod with you pump to 17 all in
Explain what the timing has to do with it in your
Like I said I’m kinda slow
Interesting there's definitely some higher understanding I thought you should be all in around 2,000 to 2,500 32_34 degrees no more advance from 2,500 on I know what you mean in stop and go it gets hot like using the above throttle blade ported timed spark port on the carb I could surpass 14:7 on the AFR with less timing full manifold I'm lucky if I get 13:3 before it starts running like crap . Cooler yes but way richer
You are thinking of the mechanical advance for wide open throttle operation.. when the engine is at part throttle and light load the timing requirements are completely different.. that is why a vacuum advance is a must for mpg and drivability! It sounds like you need a different vacuum advance pot.. which one are you using?
Andy
@@UnityMotorSportsGarage now I have a adjustable since I was running a pertronix 3 dist and the diaphragm went out at 500 miles and that design you need to pull the dist and take it apart to change it?? Who designed this? The motorcraft dist diaphragm that went out at 50 miles then I found a good ajustable I have a 390 it likes 10-12 initial then I backed the full manifold advance to about 12 /14 so I'm about 22/24 with both initial and full vacuum timing before the ajustable pod it was off the dial so I think it was about 30/35/40 way too much nice and cool but my AFR was 12 :9 .
The best power and performance is when I ran the lighter bronze spring in the front on dist initial was 14 non ajustable pod on ported or timed spark port that thing rocked although like you said it got hot in stop and go situation needed more timing at idle but for performance it was awesome 👍
You got Casper back together! Did I miss a video?
I must have missed it also
@@philipmazzuca2269 I really wanted to see the damage, and what it took to get it back together!
David- damage had to be extensive...... looked like a rod let loose
Casper is resting comfortably in the driveway. As with any hot rod it takes money and time. This was done before the Epic Fail. Stay tuned for updates on the Mixed up Boss and Casper's resurrection.
If the point of the exercise is to find the ultimate vacuum advance curve that the engine likes then why do you want to know what the timing is. You said that was important but why?
So you can plot it and adjust the vacuum pot to match what you did while driving using the mighty vac