Adjustable vacuum advance canisters?
Thread Starter
Burning Brakes
Joined: Sep 2017
Posts: 1,073
Likes: 65
From: Belgium
Adjustable vacuum advance canisters?
Hi everyone
I'm looking for an adjustable vacuum advance canister. I found some but they all look the same...
I have a 77 with original HEI. (I already got two re-curve spring kits.)
1) Is it really that helpful and does it work?
2) The Crane adj. canister looked very nice but they don't make them anymore. Is there another substitute for this one?
3) Moroso, Proform, Pertronix, Accel, ... they all look the same. Does it matter?
I'm looking for an adjustable vacuum advance canister. I found some but they all look the same...
I have a 77 with original HEI. (I already got two re-curve spring kits.)
1) Is it really that helpful and does it work?
2) The Crane adj. canister looked very nice but they don't make them anymore. Is there another substitute for this one?
3) Moroso, Proform, Pertronix, Accel, ... they all look the same. Does it matter?
Safety Car
Joined: May 2001
Posts: 4,759
Likes: 1,647
From: Fairfax Virginia
I would imagine that the ones they sell at Summit Racing or Jeg's would be right what you are looking for. They can be set and function just like the factory set unit.
The job the Vacuum Advance plays is fairly simple and I can't imagine that there too many options. I have never used an adjustable unit before so I can't get specific for you. I would definitely check the reviews as some of them appear sub-standard, the Accell HEI Adjustable vacuum seems to have a lot of bad reviews. Not good.
After reading through some of the adjustable vacuum advance advance reviews it would seem that the Proform Adjustable Vacuum advance. Here is the information and check out the reviews!
Part Number: PRO-66952C
And it is only $20
Having swapped my carburetor for a EFI system I had to remove the vacuum advance and disable the centrifugal advance mechanisms. Then the ECU can be set up with a curve of your own design. This is the best way when you have a engine with unusual characteristics and requirements.
The job the Vacuum Advance plays is fairly simple and I can't imagine that there too many options. I have never used an adjustable unit before so I can't get specific for you. I would definitely check the reviews as some of them appear sub-standard, the Accell HEI Adjustable vacuum seems to have a lot of bad reviews. Not good.
After reading through some of the adjustable vacuum advance advance reviews it would seem that the Proform Adjustable Vacuum advance. Here is the information and check out the reviews!
Proform Adjustable Vacuum Advance Canisters 66952C
4.75 out of 5 stars ( 17 )Part Number: PRO-66952C
And it is only $20
Having swapped my carburetor for a EFI system I had to remove the vacuum advance and disable the centrifugal advance mechanisms. Then the ECU can be set up with a curve of your own design. This is the best way when you have a engine with unusual characteristics and requirements.
Burning Brakes
Joined: Sep 2016
Posts: 957
Likes: 444
From: Dutchess county New York
I have to preface this with 'contact @lars to get the most current version' in case there have been updates.
The best result I had with an ancient adjustable vac advance can was to throw it to the curb and get a B26 VC1808 that worked well with my timing curve. I'm not saying that's the one for you only that you have to figure out which works best according to that curve and the attached doc has a list of different cans and their specs.
NAPA is a good source for them, or was anyway. Been a few years.
The best result I had with an ancient adjustable vac advance can was to throw it to the curb and get a B26 VC1808 that worked well with my timing curve. I'm not saying that's the one for you only that you have to figure out which works best according to that curve and the attached doc has a list of different cans and their specs.
NAPA is a good source for them, or was anyway. Been a few years.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Novushu,
The problem with some vac canisters is they apply too much vacuum with engines that have been modified.
The simple solution is to use an adjustable unit to "calm-down" all that unneeded advance.
The adjustment is done through the vac port using an allen wrench. Then tweaking the unit with a Mity-Vac to observe the gauge when the vac arm starts to move and when it stops. I believe with a low vacuum common in bigger cams, you want around 10* - 12* max.
More than that amount, and some vehicles have a tendency to "trailer-hitch". This term is the likeness of pulling a trailer one minute then the trailer pushing the next. aka Surging. This event happens at mid throttle or cruising speed.
Another add-on you might consider is a Vac Adv limit plate. It mounts under the vac arm and has four settings to tailor your needs.
I have no favorites on these canisters. Likely same manufacturer, but . . . . . read reviews.
The problem with some vac canisters is they apply too much vacuum with engines that have been modified.
The simple solution is to use an adjustable unit to "calm-down" all that unneeded advance.
The adjustment is done through the vac port using an allen wrench. Then tweaking the unit with a Mity-Vac to observe the gauge when the vac arm starts to move and when it stops. I believe with a low vacuum common in bigger cams, you want around 10* - 12* max.
More than that amount, and some vehicles have a tendency to "trailer-hitch". This term is the likeness of pulling a trailer one minute then the trailer pushing the next. aka Surging. This event happens at mid throttle or cruising speed.
Another add-on you might consider is a Vac Adv limit plate. It mounts under the vac arm and has four settings to tailor your needs.
I have no favorites on these canisters. Likely same manufacturer, but . . . . . read reviews.
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,391
From: At my Bar drinking and wrenching in Lafayette Colorado
I have to preface this with 'contact @lars to get the most current version' in case there have been updates.
The best result I had with an ancient adjustable vac advance can was to throw it to the curb and get a B26 VC1808 that worked well with my timing curve. I'm not saying that's the one for you only that you have to figure out which works best according to that curve and the attached doc has a list of different cans and their specs.
NAPA is a good source for them, or was anyway. Been a few years.
The best result I had with an ancient adjustable vac advance can was to throw it to the curb and get a B26 VC1808 that worked well with my timing curve. I'm not saying that's the one for you only that you have to figure out which works best according to that curve and the attached doc has a list of different cans and their specs.
NAPA is a good source for them, or was anyway. Been a few years.
Lars
Race Director
Joined: Mar 2017
Posts: 11,953
Likes: 4,509
From: Virginia
I'd absolutely follow @lars' advice, and email him for his latest papers.
I use an Accel 31035 with my stock-ish HEI (ZZ4 takeoff). I followed @lars' instructions to remove endplay with shims, and to set up the springs (one light, and one medium, with the stock weights, is what worked for me).
Anyway, the Accel vac advance can be adjusted to limit the total advance to 10-12 degrees. It is important to note that the available vacuum range is fixed, so this particular unit may not work if you have a big cam and limited vacuum.
I use an Accel 31035 with my stock-ish HEI (ZZ4 takeoff). I followed @lars' instructions to remove endplay with shims, and to set up the springs (one light, and one medium, with the stock weights, is what worked for me).
Anyway, the Accel vac advance can be adjusted to limit the total advance to 10-12 degrees. It is important to note that the available vacuum range is fixed, so this particular unit may not work if you have a big cam and limited vacuum.
Race Director
Joined: Nov 2006
Posts: 13,248
Likes: 7,840
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
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Cruise-In VIII Veteran
I tried 2 different adjustable vacuum advance cans. (A few years back). Convinced that the first one must have been defective, I tried another. A different brand the second time although they both looked identical. The first was a Accel brand.
Totally garbage. I ended up finding the correct vacuum advance can to match my vacuum level.
I would advise you to find the correct advance can to meet the 2 inch rule and not waste your money on these adjustable units. I believe them to be a worthless gimmick.
Totally garbage. I ended up finding the correct vacuum advance can to match my vacuum level.
I would advise you to find the correct advance can to meet the 2 inch rule and not waste your money on these adjustable units. I believe them to be a worthless gimmick.
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