timothypaul

Hey Folks -

I have been having an issue w/ my intake manifold constantly leaking.

Tried it without the seals - using straight RTV, it leaked, blew out the back of the intake. Tried it with the seals (gorilla glue on bottom to hold them in place) - still blew out (the front this time).

Going to try for a third time tomorrow, but a friend suggested there is too much pressure. I have a PCV valve on the left valve cover and a Edlebrock breather on the right valve cover. He suggested I block off some of the holes on the breather so there is more suction to the PCV valve, or eliminate the breather all together.

I'm curios if this makes sense. Getting tired of leaking a quart of oil / day.


Thanks...TIm

chadman

What condition is your motor in? Have you ever done a leakdown test on it? Maybe the PCV is plugged and needs replaced. If it is functioning correctly and you are still getting that much pressure you probably need a ring job.

rjohnson442

How is the oil filler cap? if the filter is clogged up I can see that adding pressure. I don't see a filter causing the seal to blow out though. How well does the manifold sit on the block before you add any sealer to it. Did you use a punch to dimple the sealing edges? and is it a stock or aftermarket intake?

tru-blue 442

Do the leakdown test.
Sounds like to much blowby.
After it's warm and you have driven it
a few miles, at idle, does the Edelbrock
breather smoke? Change pcv valve 1st.

oldcutlass

Tim, I'm assuming this is the the same 455 from 2011 and the same problems? Were the heads machined down when you had your engine built? If you replaced the gaskets and reassembled were all the bolts centered in the manifold holes or towards the top?

I assure you that if you had that much crankcase pressure to blow out the seals, you'd have other problems.

Octania

Attempting to seal the crankcase entirely is a bad idea.
Having one exit is a bad idea.
If you read up on the function of the PCV system, it also flows the other way under conditions of high blowby- thus the tube to the air cleaner to direct that into the air cleaner.

Blowing out the intake end seals is not proper, but closing the crankcase will not alleviate that...

timothypaul

Hmm - okay, thats why I wanted to put it here on the forums so smarter people could direct me. Yes - this is the same 455 I have had numerous issues with.

So, I am sure this has been discussed numerous times, but...

I am not going to use the seals, I am going straight with RTV. Does it matter which one I use. I always use the Permatex Black.

I am goin g to put the RTV down, wait 5 minutes and then install the intake. I was told the RTV should be tacky. I usually wait about an hour after installation to fire up the engine.

I have an Edelbrock Performer intake, I know the proper torque sequence, and I have followed the Edelbrock site for torque settings, but does anyone have a recommendation for what they know works?

Thanks....TP

oldcutlass

Have you done a dry test first with side gaskets and see where your bolts line up and what your clearance is front and back?

I like the "The RIght Stuff" gasket maker. Use 25-30#s torque, let it sit over night and retorque.

rjohnson442

X2 and dimple the edges where the sealer is.
If the blocks had any machine work over the years this may be why it won't seal properly.

chadman

I use the Permatex Ultra Gray. Don't use the black as it never fully hardens like the gray does. I also let it sit overnight before firing.

442rocketdave

X2 on the dimpling the edges both the block and the manifold and clean them and make sure they are clean and dry from oil and X3 what OldCutlass said!!

timothypaul

Ok. Got everything off. Should I remove the distributor?

MDchanic

Your choice - it makes it easier to set the intake straight down on the new gaskets and sealant, especially when bending forward under the hood, but if you have a good helper, you could probably drop it straight down with the distributor in place.

- Eric