Vacuum Gauge

[Keith W.]

[Ed H.]

Re: Vacuum Gauge

Hi Keith,

I use this one from Summit Racing - https://www.summitracing.com/parts/wmr-w80594. This one works well for my use in setting the idle air/fuel mixture.

Regards,

Ed H

[Keith W.]

Re: Vacuum Gauge

Hi Keith,

I use this one from Summit Racing - https://www.summitracing.com/parts/wmr-w80594. This one works well for my use in setting the idle air/fuel mixture.

Regards,

Ed H

Thanks Ed. I will get that on order.

[Paul D.]

Re: Vacuum Gauge

I usually use my Mityvac (brand name) hand held pump. It includes various fittings to adapt to different size hoses and includes parts to function as a break bleeder. Works great to get fluid flowing if doing a "gravity bleed". When connected directly to a vacuum source, it provides a very accurate vacuum reading. Just search hand held vacuum pump and you will find many choices.

[John F.]

Re: Vacuum Gauge

O'Rielly's should have one.

[Frank D.]

Re: Vacuum Gauge

There is not much to them and spending $14 to $20 should get you a good one almost anywhere, make sure they include "T" connectors. These gauges are also fuel perssure test gauges - surprising how many don't realize that.

[Duke W.]

Re: Vacuum Gauge

I think you can buy a Mity Vac at harbor freight for about 25 bucks. Having a vacuum pump is really useful... like for checking if your VAC is alive. Most have no idea if it works or not.

If you have a '70 with a Holley carb the engine must be a LT-1. Convert the ported vacuum advance to full time and replace the VAC with a 8" B28 (Airtex 4V1053) and quicken the centrifugal curve. Read my tuning seminar for more details.

Duke

[William F.]

Re: Vacuum Gauge

Tell me how and why to use the pump part of a mity vac to tell if vac advance is alive? Can tell if at least "alive" by watching timing change as you disconnect and connect the vac hose to vac can. Don't you use vac gauge ted into vac advance line and timing light to see if vac can is working as specified in degrees at certain vacuum reading? Guess you connect mity vac to hose to vac can and see how much advance vac can gives at certain vaccum you pull to simulate engine vacuum-correct??
Thanks

[Joe L.]

Re: Vacuum Gauge

I need to dial in the air/fuel mixture for my ‘70 Holley 4bb. Any suggestions for a vacuum gauge that won’t break the bank?

Keith-----

I bought a rather inexpensive one more than 50 years ago. It still works perfectly today. Of course, it was American-manufactured. I can't speak for the current crop. They may be just as good, or not.

[Paul D.]

Re: Vacuum Gauge

I believe you have it figured out William. By checking degrees advance vs vacuum pulled, you can sometimes identify or confirm which can you have. Will also weed out the one can fits all cans out there. Will also identify a tired can that is not quite up to spec although they usually are all or nothing in that area. Chip.

[William F.]

Re: Vacuum Gauge

Thanks Paul

[Duke W.]

Re: Vacuum Gauge

Use the vacuum pump to check that the start and stop points in inches Hg of the VAC meet spec by observing breaker plate rotation. If it meets spec the maximum specified advance is likely okay, and it can be checked on the engine with a dial back timing light.

Also, it is also difficult if not impossible to swap the VAC without removing from the car and disassembling unless you pump it down to pull the pin to the limit.

Duke

[William F.]

Re: Vacuum Gauge

Thanks for explanation and tips Duke