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.
Vacuum leak
- Thread starter da_bull
- Start date
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bob w
Still crazy after all these years!
Have you verified where the leak(s) is? Where?
looks as if its to the left and right of each of the intake runners
gene49
Well-known member
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.
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.
Old Iron
Well-known member
Have you checked the intake flange, with a straight edge, to see if it's flat? Both ways
Im going to set the intake back on the heads without the intake, and run a feeler gauge down through there to see.
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
BoB
gene49
Well-known member
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.
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 ....
once you have a clear start point ....
On a side note, I found the issue with the vacuum leak. In putting a thin bead of RTV around the ports was the culprit. I went back to doing it the old school way like I always have (no RTV on the head/intake area, only a tall bead front and rear). No leaks whatsoever. That's what I get for following Edelbrocks instructions I guess, lol...
gene49
Well-known member
Congrats. I
It didn't work that way for me (but that cold just be me). Happy its working out for you.
It didn't work that way for me (but that cold just be me). Happy its working out for you.
