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-   -   oil leak from manifold. (http://www.hotrodders.com/forum/oil-leak-manifold-223477.html)

novadan 08-28-2012 09:57 PM

oil leak from manifold.
 
i have a sbc with a tunnel ram manifold set up for fuel injection. never had a problem with oil leaking from the back of the manifold where it seals against the block until recently.

i had to replace the cam because the distributor hold down cam loose and destroyed the drive gear and the cam gear. in other words, tried pushing the distributor out the top. after all was said and done, while breaking in the new cam, the engine developed a leak from the back of the block by the manifold, i removed the manifold again, and resealed the manifold, only to have he same issue. the oil leak is a consistent drip until the engine is shut off, everything else is dry except for the back of the manifold.

my question, has anyone ever seen a manifold get warped at the back from something like this happening. and why wouldnt the sealant fill that gap if it was warped.

any information is apprecaited.
thanks dan.

DoubleVision 08-28-2012 10:41 PM

One thing to check is the oil pressure sending unit is right beside the distributor. You'll need to check it first to assure the leaks not coming from there. If your positive it's coming from where the blocks china wall meets the intake then one thing that can cause it is crank case gas build up. Since tunnel rams don't use PCV valves then I'm guessing your using breathers in the valve covers. Make sure they are both open as if they are clogged it can build up pressure to the point it forces it out. You said you used sealant on top of the china wall, did you clean the top of the china wall spotless?
Did you use the gasket with sealant on it or just a bead of sealant alone?
I never heard of the intake warping due to the issue with the distributor, however it's possible that it cracked the intake and the crack is not visible to the naked eye.

novadan 08-29-2012 06:23 AM

The second time the manifold was off. I removed the plug for the oil pressure port and also resealed that. I'm running the oil pressure sensor from a different location, the one your talking about just has a plug threaded plug in it. But I checked for leaks from there and it's dry.

I never thought about the crankcase pressure. I'm still using a pcv valve in the one vale cover and just a oil fill cap ( nonvented), in the other cover. Is that pressure that high that it could blow out the sealant.

I'm using just sealant along the back of the engine, also have and never had issues until now.

delawarebill 08-29-2012 06:33 AM

leak'n
 
i'm sure u did this.. but i mention it anyway..
if u gottta pull it again.. make sure u clean it good with a rag and brake cleaner... if u use the rubber gasket use some RTV top and bottom of it.. if not use a GOOD bead of RTV making use it ooz's out evenly... leave for at least a day to cure..
if u don't want to pull it again (can understand that), clean the area with bk clean and wipe with paper towel... put some rtv on your finger and press it in the mating surface, let that cure too...

cdminter59 08-29-2012 09:12 AM

oil leak from manifold.
 
It would be best to use a vented breather cap on the other valve cover. Make sure that the valve cover has a baffle under the breather cap to keep oil from splashing on it soaking the filter element. If it isn't baffled use a baffled grommet.

1971BB427 08-29-2012 11:50 AM

Quote:

Originally Posted by delawarebill (Post 1586791)
i'm sure u did this.. but i mention it anyway..
if u gottta pull it again.. make sure u clean it good with a rag and brake cleaner... if u use the rubber gasket use some RTV top and bottom of it.. if not use a GOOD bead of RTV making use it ooz's out evenly... leave for at least a day to cure..
if u don't want to pull it again (can understand that), clean the area with bk clean and wipe with paper towel... put some rtv on your finger and press it in the mating surface, let that cure too...

That's very good advice to let it dry for a day before starting it! I've seen more than one rear seal leak because it was sealed with RTV and started to check as soon as it was finished.
I personally don't use the end seals, but I've seen people use them and RTV them, only to have them push out from the slippery RTV when tightened. If I used them I'd only RTV the ends where they meet the side gaskets, and keep the rest dry so it holds better.


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