Main Seal
 

Hi all:
I have an engine which I built like 10 years ago. It has been sitting sealed up in the basement. This is an older 7R 2.7 case, and it was basically a basket of parts I rounded up and built the engine from (except for the thousands of dollars worth of new stuff).

So, I got it running, and the main seal at the flywheel end seems to be leaking. I hemmed and hawed about changing it, and decided it was OK. Well, it's evidently not OK.

So, I'm going to pull it back out and put in a new seal. Anyone got a guess as to failure mode? My guess it it's old, and couldn't take the rotation without disintegrating a bit.

http://forums.pelicanparts.com/uploa...1588197676.jpg

Uggh. Pulley end leaks also.

Hi Patrick,

Unfortunately when engines are not run for years the rubber seals will dry out when not kept lubricated with oil from running the engine. I am suffering the same fate with my 930 that sat for 18 years. Along with that one of my head studs broke after only running for 1,000 miles. Now my car has been sitting for four years while I save up to rebuild the engine. Hopefully I will start this summer.

Rahl

The first time I replaced mine, I had a small leak. I searched the forum and found in a thread that it is best not to set it too far in. I replaced it with another seal that I left a little further out and all was well.
Dry outside and a little oil on the inside of the seal I believe.

I broke down and bought some dye and a blacklight. Aside from the front and rear main seals, I want to identify any other leaks. I don't want to take this engine out again if I can avoid it. BTW, I just learned you can't get the engine in and out with the AC compressor mounted. I'm also going to check the leakdown while it's out. Parts will be here mid-week.

Man, that blacklight and dye works great! The only leaks are the two main seals. It was like the 60's all over again!

So, this is still installed in your car and running?

Rahl

Yes, Rahl
I'm going to take it back out today to fix the seals.

Since you are going to slit the case, have you thought about replacing all the internal oil seals or are you confident the remaining seals are good? It is a lot of work to get the main seals out as you know. I hate the thought of " I should have, could have while I was in there".

Best of luck on your project.

Rahl

Hi Rahl,
I have no intention of splitting the case I am going to pull out the two seals and replace them that’s it. This engine was just rebuilt, albeit 10 years ago.

OK, so the #8 bearing is leaking at the crankshaft seal and not the O-ring on the #8 bearing. That is good news!

Rahl

Rahl,
You got me thinking about that O-ring. It doesn't appear to be leaking; in fact, none of the rubber seals appeared to be leaking, except for the two crankshaft seals.

Fingers crossed!

That O-ring seal is why I am glad I found a broken head stud. It gives me the reason to do a complete teardown and replace that #8 nose bearing o-ring seal. Unfortunately I found this four years ago and have not driven the car since while I save up the money for the rebuild.

Best of luck,

Rahl