How to set vacuum advance on older cars

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How to set vacuum advance on older cars

Рет қаралды 37,698

pyleup

Күн бұрын

Tuning how to set vacuum advance on older cars

Пікірлер: 71

@3Repete 8 сағат бұрын

Thanks for this. I have been fine adjusting the idle vacuum advance on my crate 350. And you just accidentally reminded me that my actual condition needs to be set while in gear. My car has an automatic transmission, with a pretty sturdy converter.

@rockymini625 Жыл бұрын

Best video on KZfaq on vacuum advance and I’ve been searching forever. Thank you.

@pyleup Жыл бұрын

Glad it was helpful!

@Craignevis19 Жыл бұрын

Just for clarity. The only difference between ported and manifold vacuum is that manifold vacuum gives you vacuum at idle and therefore, timing advance at idle. If you’re hooked to ported vacuum you will not have any vacuum at idle. Therefore you will have no timing advance at idle. Only when you begin to step on the throttle will vacuum come in and timing will begin to advance. So if you set your initial timing while hooked up to manifold vacuum and you want to switch to ported vacuum you will have to increase your initial timing because when you disconnect from manifold vacuum you’re taking away some advance timing the canister added at idle. If you’re driving a vehicle with a stock to mild cam I would suggest using ported vacuum advance. A more radical engine with a big cam will benefit from manifold vacuum advance. There are lots of videos and articles on vacuum advance out there and most are very vague. Hope this helps.

@pyleup Жыл бұрын

I agree with your statement.

@alan6832 Жыл бұрын

Vacuum advance at idle gives a more efficient idle, which is important in traffic jams, and reduces plug fouling at idle, so I use manifold vacuum with my stock cam, though my worn engine has reduced compression at idle.

@28704joe Жыл бұрын

I agree with your statement: "There are lots of videos and articles on vacuum advance out there and most are very vague" I have found NONE that adequately discuss the issue as you have here. My big issue is I see the signals being 180 degrees different : With Ported vacuum your signal is zero at idle and goes to vacuum with throttle opening. With manifold vacuum you start with a vacuum signal and it goes even lower with throttle opening. I think I just identified my reasoning problem here........ I'll get back to you. Thank you for posting I believe I just learned something.

@alan6832 Жыл бұрын

@@28704joe One could just keep bumping it up every week or so until you get a sign that something is too hot, like hearing spark knock or seeing a really hot spark plug, but one can do the same with base timing too, except I can't because my engine has lost so much compression with wear that it still runs cool with the base timing so far advanced that it tries to start backwards, straining the starter motor, so that leaves me with vacuum and centrifugal advance, but even without natural disasters, I idle enough to want an efficient idle and so use manifold vacuum. I also don't want the plugs to foul while idling.

@brucemashburn1579 8 ай бұрын

Great video. But I too agree with Craig. If using ported vac there will be no pull on the distributor until you begin adding throttle. So, if someone wants to keep attached to ported vac (as a lot of people feel is appropriate), do I set my initial timing to the manufacturer's specs? Or do I need to add additional timing as Craig suggests. This is in a Ford 460 that has been rebuilt. Pretty much stock. And, I can't seem to dial the vac canister below 15. Are some vac cans made to require more vac than others? I would think it would be able to dial it down to 10 or so ......at least.

@shawnrivera3071 3 жыл бұрын

Short and to the point love it

@nickrodriguez7293 11 ай бұрын

Thank you for your explanation. I enjoyed your explanation.

@pyleup 11 ай бұрын

Glad you enjoyed it!

@GJJC13 Жыл бұрын

Great video. Very simple & quick. Do you remember what adjustable vacuum can is reliable (Brand / Part #)? I also read that if the can is not fully working this can affect your mpg? How so? Thanks

@mikeuva2273 Жыл бұрын

you explained that great nice job

@pyleup Жыл бұрын

Thanks!

@joshuagarvey9362 2 ай бұрын

Great video thanks.👍

@pyleup 2 ай бұрын

No problem 👍

@nursecuenca Жыл бұрын

My 350 chevy small block is hooked to only manifold vaccum. I tuned it to 12 degrees tdc. When I place vaccum gauge the best I could get to tune is at 14 gh vac. Any suggestions? And if I open timed vaccum from distributor will that increase that number?

@OG_DSM 3 жыл бұрын

This is a great way to explain how this vac advance works. I purchased an 87 Starion that has Vac Ad and it has a misfire under wot. It pops and leans out on my af as my foot goes down. It was making over 18lbs of boost and suddenly, can't get past 5 or 6 without a band and pop. Could my vac ad be out of whack? Haven't changed the plugs nor the distributor yet. I plan on checking the vac ad to see if it holds pressure... At idle, I feel no suction on that line and it goes right to the throttle body. Any suggestions would be great!

@pyleup 3 жыл бұрын

Vacuum advance should play no part when in boost . it's only at idle it has an effect.

@OG_DSM 3 жыл бұрын

@@pyleup OK... That's good to know.

@JoeVinson Жыл бұрын

So, do you want it to be equal to the vacuum your engine is pulling at idle? Thank you for this video!

@pyleup Жыл бұрын

yes

@johnc7431 2 жыл бұрын

I'm really curious I have my vacuum advance coming off my distributor on the side of my carburetor. Should I be hooked up to the manifold vacuum for this to work correctly

@pyleup 2 жыл бұрын

I hook mine to the baseplate on the carb but it's a manifold vacuum port. some carb ports will not give you full engine vacuum and I set all my vacuum advance cannisters to manifold vacuum you want the same vacuum you measure with a vacuum gauge . to set your cannister.

@butchking154 2 ай бұрын

iv seen a lot of vids and out of all of them this is the best one i seen on how to set your adj vacuume canister very well explained

@pyleup 2 ай бұрын

Thanks

@paulthompson1654 4 ай бұрын

U forgot the No1 point . Vacuum advance occurs at light throttle steady state cruise ie between 27mph ---- 55mph . U set the xtra advance between these vacuum /road speed points . If u still have a very basic distributor u may need xtra advance pending your setup so either manifold or ported setup might be better for you . When u have standalone programmable timing idle timing and cruise advance can be what ever u want

@Skeksi_Man 2 жыл бұрын

My 1977 Camaro (250 inline 6 automatic) has a dead spot / hesitation just off idle when I hit the gas pedal from stopped and when I hit the gas pedal from cruising. I’ll hit the accelerator and it momentarily feels like it’s going to stall before the car springs into action and then it runs fine Sometimes it causes the car to stall completely when I accelerate around a sharp corner or bend unless I coast it and accelerate gently. Could the vacuum advance cause this ? I’ve already had a carb rebuild , accelerator pump and new fuel pump.

@pyleup 2 жыл бұрын

Sounds more like a Carb problem. Check the vacuum advance canister to see if it's holding a vacuum and that it's plugged into a manifold vacuum port. Also check your base timing and make sure it's set between 10 and 12 degrees. Make sure the vacuum canister is unplugged when you check the timing.

@pyleup 2 жыл бұрын

The carb may have been rebuilt, but I'm wondering if it was properly adjusted - idle mixture settings and accelerator pump adjustments. What you are describing, the bog, sounds like a temporary lean fuel condition before the main jets are flowing enough gas for the engine to stabilize.

@S_C_A_R_F_A_C_E 3 жыл бұрын

So just for the record, the vacuum advance canister should be pulled in to the max at idle?

@pyleup 3 жыл бұрын

Yes and that's the point of the video, if you have low vacuum at idle or the canister is bad it may not pull in at all or only half way, big cams can cause this .

@S_C_A_R_F_A_C_E 3 жыл бұрын

@@pyleup So we want to adjust that canister screw so that there's barely any advance timing while idling because if there is none then there will be a flat spot or delay after hitting throttle.

@pyleup 3 жыл бұрын

No that’s not it , you want Full vacuum advance timing at idle not part or none of it ,the moment you hit the throttle vacuum will drop and vacuum advance timing will drop out then you will be running on centrifugal advance of the distributor and what ever that timing curve is up to it’s max like 30 to 35 degrees at 3000 rpms. Vacuum advance is only for idle it will make it easier to start and idle better off idle throttle will be better street running. So you want to adjust it so you have full vacuum advance timing at idle.

@kevinragsdale6256 3 жыл бұрын

I cant figure out how to tune/set up the advance on my 300 i6, I stuck all size allens in there and couldnt find anything to bite.

@pyleup 3 жыл бұрын

If you can,t adjust it a least you should be able to test it to see if it is working and at what vacuum it comes in at and test your vacuum on your 300 I6 . If it,s stock the only thing you need to worry about is if it works or not. The cannister can be bad. you need to pull a vacuum on it to see if it works.

@mickangio16 Жыл бұрын

Not ALL cans are adjustable! The only ones that I know of that ARE adjustable have the hex shaped nose like in the video.

@theungoliant9410 Жыл бұрын

what size allen? counter clockwise to be all in sooner?

@pyleup Жыл бұрын

Sorry, I don’t know the exact size of the Allen, but turning it clockwise reduce the amount of vacuum it takes to pull in sooner

@thejodyg 3 жыл бұрын

which way do you turn the wrench to lesson the amount of vacuum that it takes to advance the timing?

@pyleup 3 жыл бұрын

clockwise worked on mine but I recommend retesting it with a meter to verify

@thejodyg 3 жыл бұрын

@@pyleup ok thanks

@S_C_A_R_F_A_C_E 3 жыл бұрын

@@pyleup So just to be sure,, the vacuum advance canister should be pulled in to the max at idle?

@pyleup 2 жыл бұрын

yes

@alan6832 Жыл бұрын

@@28704joe You want vacuum advance at idle to have a clean and efficient idle, since there is little danger of spark knock at idle. Without it, you run the risk of running out of gas in huge traffic jams associated with disasters like Katrina.

@davidpalmer9503 3 жыл бұрын

If I loosen advance is that less.tighten is more you did not mention

@pyleup 3 жыл бұрын

Every distributor will be different. If you test it with a vacuum tool you will know which way to turn it . But you have to be watching it with the distributor cap off, otherwise you will never know if you're doing it right or not. You can't just turn it cw or ccw without testing it. Some stock distributors can't be adjusted, but you can still verify that the advance is working by testing.

@cocopublicnews6766 2 жыл бұрын

Can the vaccume advance keep a older car from starting

@pyleup 2 жыл бұрын

It will make it harder to start but it won’t stop the car from starting itself it’ll just run rougher without the vacuum advance hooked up

@joe-hp4nk 2 жыл бұрын

Do you use the ported or unported for the vacuum advance?

@pyleup 2 жыл бұрын

unported manifold vacuum at the base of the carb but sometimes I will use ported carb vacuum on certain situations. A lot of factory muscle cars had ported vacuum at the carb for the distributor vacuum advance. As described in the video you can check these parameters in ported or unported situation’s and adjust the vacuum advance accordingly.

@joe-hp4nk 2 жыл бұрын

@@pyleup I tried both and fine ported worked the best, no vacuum advance at idle and vacuum advance at part throttle. Manifold vacuum did the opposite which seem to defeat the purpose.

@HonkeyLee 8 ай бұрын

This number 13 is that the amount of vacuum in drive or park?

@pyleup 8 ай бұрын

Park

@tdalexander8859 3 жыл бұрын

I have a '67 Cad deville w/429. Im having what feels like missing at acceleration 35 mph to 55 mph. Been told to replace dist but dont believe that is necessary? Im afraid its just a keep replacing parts to fix mindset. Im wondering about the vac advance? I got new part and when I pulled off old vac advance and found oil inside of it? Any idea why??

@pyleup 3 жыл бұрын

The vacuum advance canister may be leaking. The vacuum leak would pull in any oil from the surrounding area in the engine. If the vacuum advance canister doesn't hold a vacuum, it is bad.