327 with a stubborn oil leak, help

I have a '63 small journal 327 in the roadster that has a leak between the timing cover and oil pan when running, no leak at the balancer, that seal is fine. it'll sling a drop every few seconds through the gap between timing cover and oil pan right in the middle. Fresh rebuild, only about 1 hour running on it. I've tried two different front pan gaskets so far. I know there are thick and thin rubber front pan gaskets, I tried the thick gasket and couldnt even get the pan on. So then I used the thickest of 3 thin gaskets, because they varied a bit from kit to kit and I had some extras. I use RTV at the ends, it looks to be leaking from the center anyway.

What am I missing, i've never had a smallblock leak there? Thanks for any help...

 

Genuine GM pan or made in China pan?

 

i always put a thin coat of silicone on the whole rubber seal. Is it a chrome pan and or timing cover? If so you might want to scuff the sealing surface with 100 grit sand paper before applying the rtv ,gives it something to stick to.

 

pan and timing cover are stock chevrolet and have no bends or dents that I can see

 

Did you put the oil slinger on the crank-between the block and balancer (inside the timing cover)?

 

You're saying you silicone the whole area of the gasket where it mates to the pan? never had to do that before, but theres always a first time.

 

Yes, but a thin layer with your finger ,not half the tube.

 

Also , make sure the pan isnt dimpled were the bolt holes are.I have seen this many times from being overtightend .If they are put the pan on a hard steel table or something sturdy and flatten them back out with a hammer.

 

I had a similar problem. Easy fix in my situation. On a cold motor, by hand degrease all around the area all the way up to the flat flange. Degrease it again. Degrease it again with Q-tips in the grove. Apply a very liberal amount of permatex on the outside around the entire curve. Gently finger wipe it flat. When you get on your feet and look you will never see it. Wait 12-24 hours. It worked on my motor.

 

did you use the correct front pan seal? there is a thick and a thin , most gaskets sets come with both

 

I had the same problem once..I learned that one hole at the front of the engine where tri 5 chev front motor mounts needs to have a short bolt in it...The same hole that the fuel pump rod is behind...

 

Sounds like crankcase pressure not venting properly.....BTW the thick seal looks like it aint gonna fit till its buttoned down.

 

It needs the thick seal.

 

With the thick seal i would have had to almost beat the pan on, is that normal? Do early motors usually use the thick seal by design?.. I wondered about crankcase pressure, but with the oil tube in front and the vent in back of the block, dont see how that could be an issue?

 

I cant think of the last time I used the thin seal. The thick seal is kinda tuff but you shouldnt have to beat it.

 

depends on what you have on the oil fill tube...a cap[as some had] or a breather[working or not?]...
I think really a PCV valve and at least one open breathin breather are necessary really.....

 

well, either way i'm gonna have to drop the pan again, Guess i'll try the thick seal again first and really push hard on the pan to see if it will go over the seal, if not then it's gonna be silicone on the other one.

 

I use oil pan studs, the thick seal, and silicone.

Overkill? Maybe.

Leaks? Never.

I prefer it that way.

~Scotch~

 

if you take the pan back off, check the measurement with a tape measure or ruler...if its 2 3/8 it needs the thick seal....if it measures 2 1/4 it needs the thin seal

 

i was thinking it could be pressure build up as well, if your breather that goes on the oil tube is used it could be pluged some, pull it off and soak it in some thinner, cant hurt, i like to use silicone around the front of my pans as well, first i clean it off with laquer thinner, with the correct gasket you should have about 1/8" of crush on the 2 front pan blots, i also have left the gasket out and just used silicone, run a nice bead and let it set for 20 min then bolt the pan on.

 

Why hasn't anybody recommended'yellow death','gorillia snot' ?? 3M weatherstrip adhesive applied to the pan lip.block, and both sides of the seal. I thought this was standard precedure,with a sbc.. Works way better ,than silly-cone with hot oil...

 

this stuff is okay around fuel/oil? Always though it would dissolve weatherstrip glue?

 

I KNOW its been rebuilt and I can't see a rebuilder missing it, but if they reused an old timing cover they may have missed it...sometimes the old chain gets so loose that it wears a slot in the side of the timing cover, right down by the crank sprocket.
Passenger side IIRC.
The oil runs down and drips right where yours is dripping.
Wipe it carefully with a rag to prevent slicing your fingers and check it out.

Might not be your problem, but I'll put it up anyway to help someone who may have the same problem in some other SBC engine and be searching old threads for answers.

 

Hey Bill, I should be able to see if this has happened from the bottom with just the oil pan off, without pulling the timing cover right? I'll probably tear into this late tonight so I want to have every scenario covered, but it would be great not to have to pull grill shell, radiator, water pump, et al for the umpteenth time.

 

Naaaa...you'll see it if its there AND your looking for it...long as you can get your head in far enough!

The crack in mine was shaped just like the letter "H"...watch for sharp edges if your sticking your fingers where they shouldn't be!

Naturally, I found my leak AFTER replacing the seal on my old 73 Chevelle daily.
Couldn't just weld it up because the chain and sprockets were obviously history for that to happen.
Old thing still ran good too...odd.

 

I have been using the 'Tuff Stuff' sealer between the seal and the timing cover (right before I put the pan on). Never had that problem.

 

Hi read your problem..I have one like it ...before I take the oil pan down again I am going to try a product put out by Permatex and it claims aftering cleaning the area and spraying their product on it 3,4,5 times it will seal the leak...This spray so they claim is pulled up into the space/gap and it fills it...I will see what happens..I think the part # is 82099 and called spray and seal...It appears auto zone and pep boys sell it...Miller

 

Racefab has it right. I just put a pan on my 327 this past weekend. Measure it. I measured mine, and needed the thick seal. I used RTF sealant on the pan and both sides of the gaskets and seals. No leaks, even though I was trying to shove it on from underneath and hold it with one hand and put bolts in with the other. It even dropped off a couple of times and the gaskets moved around a bit. Still no leaks.

 

i have had a chain wear a hole in my timing cover as well, had the timing cover off like 5 times, new gaskets and seals over and over, the last time i had the cover off i found the hole, just a tiny little slit that you almost couldn't see from the outside, brazed it up. no more leak.

 

are you tightening to correct torque? or over tightening?