Vacuum leak

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da_bull

Well-known member
Joined
Sep 8, 2019
Messages
51
I know it should be a simple thing but I guess I’m not holding my mouth correctly. I have a SBC with an Edelbrock tunnel ram and 2 500cfm Edelbrocks. This is the second time I’ve put intake gaskets after removing it to fix a small oil leak. I've always installed them dry. I installed a dry set on this intake a couple weeks ago. It leaked at most all the intake ports just a little. I downloaded the install pdf for this intake for their torque sequence and spec to make sure I was doing it correct, and that's when I read about the gasket maker. When I pulled that intake off in the first place to fix a rear oil leak, the previous owner had gasket maker on the front and rear of the Felpro gaskets, and I chastised him for it under my breath while scraping it all off, but I didnt have any vacuum leaks before. It looks like more than is really there. It's just a thin layer, smooshed flat with my finger, and I made sure there wasnt any in the intake or water ports. I am wondering if its just because its a thin (1/4"ish) cast aluminum (unlike a Performer intake that has more support at the runners). Started it up today and it still has a leak at the intake runners. Any advice? Thanks in advance.
 

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Years ago I started putting a thin layer of form a gasket around the intake ports and water ports on both sides of all the intakes gaskets I have installed. Don't need but a thin coat, but it sure solved a lot of leaks. I don't believe the gaskets are as good as they used to be either.
The old parts have had years to have surfaces scarred, scrapped uneven, and warped by improper torque sequences a bit and there are no guarantees the new stuff was ever milled correctly in the first place.
 
I had that problem with my old Edelbrock medium riser, it leaked at the 4 corners but it was easy to pin down because it leaked oil in those spots so I just put an extra dab there!

BoB
 
I watched a "mechanic" replace intake manifold gaskets a few years ago. The guy clean up the gasket surface with one of those 3M roto discs on a 90 degree grinder! He was so impressed that the surface came out so shinny. I suggested that maybe he would want to put a bit of sealer on the intake gaskets. He also looked at me like I had 3 eyes. When he got all done with it, he had coolant and vacuum leaks. I don't believe he ever figured out why.

Maybe that mechanic worked on the intake you are working on, before you were there.
 
I watched a "mechanic" replace intake manifold gaskets a few years ago. The guy clean up the gasket surface with one of those 3M roto discs on a 90 degree grinder! He was so impressed that the surface came out so shinny. I suggested that maybe he would want to put a bit of sealer on the intake gaskets. He also looked at me like I had 3 eyes. When he got all done with it, he had coolant and vacuum leaks. I don't believe he ever figured out why.

Maybe that mechanic worked on the intake you are working on, before you were there.
Ouch, I was a little nervous using the rubber Roloc disc to get the old sealant off, but I knew it wouldnt take any "material" off. On a side note, I did take a 2' straight edge along the head and intake surfaces. They are all surprisingly very straight.
 
get it running and spray some brakecleaner around the inlet manifold, when the motor speeds up a little there is where the leak will be,

once you have a clear start point ....
 

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