VCCA Home Forums GENERAL DISCUSSION New User Forum Rear main rope seal

If anyone has replaced/installed the two-part rope seal in the rear main (without pulling the engine) with the tool that is made to hook into the old rope and pull it out and pull the new in thru, I would highly appreciate if you could share your experience doing it before I start.
Thanks.

I’ve done it many times on Chevys Pontiac and Oldsmobile usually it works sometimes to be turning the crank while pulling the old one out and the new one in. Also have the new one oiled.
When I worked at the Pontiac dealer if you did a rear main seal under warranty you replaced the lower rope and cut off pieces and packed into the upper half. No matter the job was usually a pain.

I have done it on both my 216s, successfully. I had the transmission pulled back and dropped the rear of the crankshaft by about 1/4”. I believe a good seal can only be achieved with all the main bearings adjusted to minimum clearance. I use the Lucas oil additive to lubricate the seal. I pulled it around with picture hanging wire. I recommend the Best seal.

Thank you!
Yeah I expect it to be a pain but I don’t mind that, I just want to do it right.
I like the idea of turning the crankshaft over to help it come out and help the new piece go in. Hopefully I can do it without separating and lowering the transmission or I might get in over my head. I guess I’ll find out.
I’ve got a tool they used to call a “Sneaky Pete” to hopefully help me grab the end of the old one and to pull it out and to pull the new one through.
Thanks again.
……-
I’m thinking of putting a dab of permatex gasket sealer on the ends where they join from top 1/2 to bottom 1/2 also.
If that’s a mistake please let me know not to do it.

I recommend an original GM seal. they are the best and can still be found. I always used permatex # 2 on the ends.

Based on your signature you might be working on a 1938 216. They do not have a rear main seal. They use a slinger to control oil going out the rear main bearing.

It is a 1938 Chevrolet 1/2 ton HC pickup.

Good catch again Rusty!

Rusty is correct, there is no rear main seal in a 1938 engine, just an oil slinger.
Adjust the clearance and make sure the drain hole
is not plugged and that is all you can do.

I believe there was a thread about making a groove in the lower shell of the rear main to allow the pressure to drain to the front. If I am not mistaken there was a photo of the modification.

Here it is:
https://vccachat.org/ubbthreads.php...39-engine-rear-main-seal.html#Post156464

Thanks

Okay thanks.
Does the engine have to be removed to adjust the clearance ?
Is it done by adding a shim or some other way?
Looks like it’s supposed to be not more than .002

Oh boy.
Now people are telling me there is no rear main rope seal on a 1938.
Gotta do something, pretty bad leak. Several drops a day.

If you do what is suggested in the above reference, you will have the best possible outcome. You don’t need to pull the motor, just drop the pan.

Several drops maybe a normal loss, Walmart sells pans to go under cars to collect minor leaks.

Dave

A 1938 Chevy that does not leak some fluid probably doesn't have enough fluid to lubricate properly. The are not like modern vehicles that almost don't leak.

Yep, the old saying is that if an old 216 isn't leaking oil it is probably out of oil! I have 3 old Chevys and they all leak oil. I just live with it. LOL

Thanks

There is a possibility that when I pull the pan the rear pan gasket section is leaking.
Hopefully so.
That would be an easy fix.
The pan gasket is in 4 parts so -maybe.

Be sure to check out the oil pan gasket thread at the beginning of the 46-48 section. There is a way to do it correctly, wish I had known that the first time or two I did it.

Dave

to stop the no sealed engines from leaking and from the book"The Cast iron Wonder" I did the following with good results.

First remove cap to block shims to get the clearence down to .002"

Next using a hack saw blade cut a grove in the bearing babbitt from the center oil grove to the front of the lower bearing I did mine just off center,
This will reduce oi flow to the rear of the bearig.
I drove my 1939 cross contry at 65 MPH (3.73 gears) many miles with no leakage and no problems.
See the thread on proper oil pan gasket istallation as previously advised.
Also make sure breather pipe is not plugged-up

Your idea makes sense.
However When my engine was rebuilt they did not pour Babbitt but put in insert bearings.
It has been fine for many years but I’m not sure if it would weaken it if I cut a groove in it.
Maybe I could just make a small shallow cut and be okay since it would be only from the center forward and a little to one side.
I wouldn’t think it would take much of a groove to get the oil to go forward instead of leaking out the rear.
Thanks for the idea.

All crankshft bearings have a babbitt lining, insert or not including 2021 cars. The babbitt iis applied to the insert for all 6 cylinder Chevrolet engines.

Oh ok thanks.