Engine and Transmission Tech

Can't imagine why but I always seem to get the difficult problems. Here's one that has me entirely buffaloed, but moybe someone will have some sort of an idea. For reference have a look at the series of photos on this page:
[forum.britishv8.org]
What you are looking for is the top of the lifter valley tray at the back of the intake manifold on the right side. This top surface is the location of an oil leak that then runs off the back of the tray and down the side of the block, dripping over the starter and running down the transmission adapter plate. While not a gusher exactly, by the time the engine has warmed up that corner of the plate has enough oil on it that swiping my index finger across it pretty well soaks my finger and it would run off if I let it. There would be several good size drps on the floor and a fairt amount of oil on the engine as well. So it's a lot more oil than can be ignored under any circumstance.

The question is, where does it come from? The valve covers seem to be sealing just fine. There is no oil on the top of the intake, no iol on the opposite side, no oil at the front of the engine. Seems even a hole in the side of the head would be diverted by the valley cover plate.

Any ideas?

Jim

Are the intake bolt holes blind?

I'm shooting in the dark here, but consider

1. Bolt holes that are tapped through into an area with oil.
2. Pin holes in welds- these can often be fixed with a center punch. It really does work.

I have fixed several leaks over the past years with RightStuff gasket maker on the OUTSIDE of the leak. It is really amazing stuff. It's can be a pain for disassembly. I think of it as rubberized JB weld.

Great question Carl! You beat me to it while I was typing.

They are Buick 300 heads, I've never heard of that sort of thing but who knows? Could be. I'm pretty sure the oil galley for the rocker shaft is at that corner but if it was leaking past the head gasket it'd come out below the tray, not above it. I guess I could start pulling intake manifold bolts and look for one that is wet.

Jim

Well. you said that the valve covers weren't leaking. Where else can the oil come from to be on top of the tray? The intake bolt holes, if they are not blind. They are on a 215. I don't know on the 300 heads.

The reason I ask is because there are some engines where too long of an intake bolt will hit the pushrod. So, checking for wet intake bolts would be be a good idea.

Anyone have a 300 head to check the intake bolt holes? Check them all, because the SBC only has four that go into the pushrod hole.

Mike Moor says they are blind on the 300.

Still don't know why it was leaking but maybe I fixed it. I went round and tightened up all the intake manifold bolts, all of them took 1/6 turn or better, some of them weren't much more than snugg. Guess the initial heat cycles loosened them up. Anyway I just ran it and though I checked it hot and it was too warm to do a thorough job my finger came out dry so I'm hopeful that was it.

Still doesn't explain how the oil was getting on top of the tray but maybe Carl was on to something. Mikey says the 300 holes are blind but maybe there was some sort of leak from the tray/head seal into a bolt opening.

Jim



Edited 1 time(s). Last edit at 06/29/2014 06:40PM by BlownMGB-V8.

Well I guess not. Just looked again and the oil is there. But that's another clue, it must come out somewhere farther away. After it cools down again I'll have a look at the oil sender tube. It could possibly be nicked in just the right spot to drip on the front corner of the intake and run down on the tray possibly. Hope so, that'd be an easy fix.

Jim

Not the oil gage line...