Vacuum Pump Recommendation?

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May 31, 2020 | 07:50 AM

KJLive

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Instructor

Joined: Apr 2005

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From: Lebanon PA

Vacuum Pump Recommendation?

Hi. I am not very mechanically inclined and was hoping for some recommendations from forum members. A while back a friend installed 2.02 aluminum heads on my 350 CI (not original), motor. After the change, I needed to purchase a larger intake. Since the upgrade, the wipers and headlights will not work. I tried a variety of different suggestions to no avail. Since the car is fully customized and not original, someone suggested just purchasing an electric vacuum pump opposed to searching for answers to correct the original vacuum system. Any recommendation on what I should consider purchasing? Thanks in advance for your help.

May 31, 2020 | 09:18 AM

68blvert

Racer

Joined: Jan 2016

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Are you sure the main vac line was hooked back up? Since both systems are completely dead, sounds like no vac feed.

May 31, 2020 | 10:45 AM

Bikespace

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From: Virginia

Did you get a new cam at the same time?

I'd look for the simple stuff first (vacuum leak in a hose, incorrect routing, or missing hose), then look for vacuum leaks elsewhere. A vacuum gauge will make this a lot easier. What is your idle vacuum now?

Have you done the @lars style tune, to include setting idle mixture to maximize idle vacuum?

May 31, 2020 | 04:59 PM

KJLive

Thread Starter

Instructor

Joined: Apr 2005

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From: Lebanon PA

Yes. Everything seems to be hooked up correctly. I checked and double checked I also bought a new filter.

May 31, 2020 | 05:01 PM

KJLive

Thread Starter

Instructor

Joined: Apr 2005

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From: Lebanon PA

I did not get a new cam. The vacuum seems to be building, but not enough. I have not tried a vacuum gauge and probably need to also consider this step.

May 31, 2020 | 05:41 PM

Bikespace

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From: Virginia

A vacuum gauge will help you diagnose the problem, and help us help you. You may also want to pick up a pack of vacuum caps to help isolate the problem to a specific system. If you engine is making good vacuum already (or can be tuned to do so), you don't need a vacuum pump. Hopefully that is the case.

May 31, 2020 | 07:11 PM

7T1vette

Team Owner

Joined: Jan 2006

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From: Crossville TN

There is a line disconnected, somewhere. Normal vacuum sequence is from intake manifold to vacuum reservor, then split to the various vacuum-operated systems: headlamp buckets, wiper door, and HVAC system. Follow the vacuum source line to make sure routing is correct and no connection point is left open.

Jun 1, 2020 | 07:35 AM

Jebbysan

Dr. Detroit

Joined: Mar 2012

Posts: 10,097

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From: New Braunfels Texas

Put a vacuum gauge on it.......set the timing per Lars sheet, post your results. Timing can cause low vacuum, so can an intake leak. Simply changing the heads and/or intake will not lower vacuum.
After setting timing.....set idle mixture screws for highest vacuum at idle.
If your system worked before.....it will work again.....

Jebby

Last edited by Jebbysan; Jun 1, 2020 at 07:35 AM.