VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 rear main oil seal leak (rebuilt 216)

Newby here. 'Just bought a '41 2 door. It came with receipts for a complete engine rebuild - bored, shaft turned, insert rod bearings, hardened valve seats, etc. The total bill was a rediculous $7057.08 for which the PO paid $6470.00 cash on 3-3-06. Yeah, folks still do that to folks who don't know any better. At that rate, it should be a fine 216!

'Had it about 2 weeks and have put about 150 miles on it. Put 1 & 1/2 quarts of oil in it today (not smoking). Drove it home about 40 miles and it is down a quart of oil. It is leaking at the rear main. I tinker but I'm no machanic (small shade tree). The PO had to know this (an honest seller would have mentioned it).

I assume I can pull the pan, drop the rear main cap and replace (only) half of the rear seal. Should I use rope or the rubber seal? Any and all experienced suggestions will be greatly appreciated.

Thanks

http://www.ebay.com/itm/Lisle-27000-Sneaky-Pete-Tool-/400287814593?forcev4exp=true&forceRpt=true

I'd try this.


Many say that a inline 6 will leak no matter what you do, I don't believe that...just sayin

7 GRAND for a rebuild?

You can buy a LS3 Vette engine for that..

My guess is that the rebuilder used a rubber seal - which only works in a 1955 or later block. Will cause a massive leak in the prior years.

Yeah, two crate engines and change left over!

Thanks, that could be it. I was not sure which type seal to use but you've answered that question. I'll try the rope type and hope it workes. She's leaking pretty bad.

Are there any tricks to installing the seal? I assume I can only get to the lower half.

Say, if he used the rubber seal, replacing just the lower half ain't gonna solve my leak. How am I going to replace the upper half?

an experiment that I did was to use te rubber seal but install a .045" thick tie strap in the bottom the the seal grove. This brought the deal out farther so the lip would cotact the crankshaft flange. In ding so it make the seal too long. Using the main bearing cap as a guide I ground the ends off the seal to get it at the correct length. There is a steel core insine the seal. It is very difficult to install the rope top seal so it will not leak.

Were you able to replace both the upper and lower halves of the seal using this method?

How successful was your experiment?

Thanks

OK, re-reading I see you did both upper and lower ('Sorry 'bout that!).

I assume you stopped the leak.

Where can I source the tie material? I'm gonna try it.

With all due respects to Chevy Nut, I would replace the top and the bottom seal with a rope seal. The Sneaky Pete that wawuzit points out is the tool you need to do the job. The top part can be fairly easy to install.
BUT, let make another suggestion. The crank has two alignment pins in the large end that the flywheel bolts to. Occasionally those pins get removed during a rebuild and sometimes are not replaced. This leaves a nice 3/16" hole from the inside of the engine right out the back of the crank which can easily disguises itself and a leaking rear main seal. I would check and be sure both pins are in the back of the crank before I did anything else.

Before you go any further you need to do some inspections. Check the rear of the valve cover and see if any oil is leaking from there. Clean and inspect the side cover in the lower rear corner. If you score a 100% on those two items then you can worry about the rear main. In any case "do your homework" first before heading into an engine repair.

What year did they introduce the rope seal?
I seem to remember someone on Chatter saying rope seals werent introduced until 46 or 47.
Tony

I wasn't able to use the Sneaky Pete because it took up too much of the seal length. I used picture hanging wire and I tied it to the end of the seal. I pulled the transmission and lowered the crankshaft slightly to do the job. The big challenge was getting the rope seal out of the top. My rear main does not leak and it is an NOS type "rope" seal. The engine I am talking about is my 1951 216 but it is very similar to yours in this regard.

The first rope seal was used in 1940. Prior to that there was no seal.
The problem with pulling a rope seal through the very small opening is that it stretches the seal thinner. It would be important to pack the seal in tighter after it is installed.
The Chevrolet 8 cyl. engines used a rope seal up through 1958. The 6 cyl 235/261 used the rope they did sell the "rubber" seal for 1955-1962 6 cyl engines in the early '60's.
Oldsmobile used a rope seal on their 8 cyl. engines right up to the last Olds 307 in 1990.

If you find you have the rope seal it may be possible to "tighten" up the upper part. A friend of mine had his repaired by replacing the lower half and the upper had a wire placed/threaded between the seal and upper surface.This wire was left in place to compress the seal tighter to the crankshaft, much the same as Gene explained regarding the rubber seal. If you do replace with the rope type be careful where you purchase the replacement as some are just plain junk. Could be the rebuilder used one that was not what folks on this site would recommend. The correct "good" seal can be purchased from either the Filling Station or Marx Parts. Both have web sites www.fillingstation.com or www.marxparts.com.

'Been gone all day.

My thanks to all for your advice and experience. I need all the help I can get.

I guess I'll order the rope seal and try that. I have ordered that sneaky thing.

I suppose checking for the alignment pins requires removing the flywheel, which requires removing a LOT of stuff. Is there any way to tell if the pins are in place without pulling the flywheel?

I haven't worked on a 216 since about 1956 and then it was limited to several valve jobs. 'Never worked on the bottom end. So, I do appreciate all the help I can get.

Don't think I'd lose sleep over the possibility your missing pins...Unless maybe it continues to leak after the seal repair...No, unfortunately there's no other way to tell, short of removing everything...Yeah, that "pete", he's a sneaky one alright...

I would think that if the pins are missing the oil would be visible on the forward face of the flywheel and with the spinning of the flywheel be all over that front face. It would then be thrown all over the bell housing and even into the starter. Knowing most shops don't add any extra work that they don't have to I doubt they are missing.

I'll look it well. I'd hate to pull everything to get to 'em.

Thanks

It's easy to check for the pins. Drop the flywheel "dust" cover and just take some wire and poke it through the alignment pin holes. If the wire goes right through, you know where you are. If not, I agree to checking the valve cover fit at the rear and the lower rear corner of the side cover.
All in all, if you can think of all the places a Chevrolet inline can leak, check it because any possible place is a possible place!

Thanks, 6cyl. I sure hope the pins are in there.

I will look for any and all sources of the leak/s. A quart in approx 40 miles is a pretty big leak! I hope to get it on a rack by Monday. I'm dreading this mess. It wasn't part of the "deal".

Thanks

I would think that if it were a missing pin, the leak would be very large and the clutch would be saturated with oil.

That sounds good. The clutch seems normal. I have a friend who has a rack and has done this before. I'm gonna hold him a light and watch! ('Soon as the gaskets and seal get here.)

I appreciate all the help. I thought I was gonna have to do this laying in my garage floor til I talked to my friend (at church this morning).

You see!, going to church is not all bad.

It works for me - wouldn't have it any other way.