Undersized Main Seal?

Stretch32 · 12-13-2022, 06:16 PM

I put oil in my recently rebuilt engine and, before I had a chance to start it, it left a puddle of oil that came from the main seal. I had my crank turned first under and I’m wondering if I need a main seal that is also undersized to accommodate this.

I read that such a seal exists here in the forum but I can’t find one in Elring or Kaco brand if they do. I’m also not sure if the end of the crank where the seal rides has been turned down requiring a smaller ID seal.

Has anyone encountered this or have a suggestion on what seal I need to replace the one that’s leaking? As a side note, the current seal is most likely a Victor Rintz that came in a Wrighttwood Racing engine seal kit so I now know they’re not the best.

Thanks!

Stretch

fanaudical · fanaudical's Garage

I'm going to reference this photo from the bonus CD of Wayne's engine rebuild book:

Pelican Parts Photo Gallery - Engine Rebuild Bonus CD-ROM Photos - Chapter 2

My opinion - The shop that "undersized" the crank should not have touched the flywheel flange. There are no bearings on the flywheel flange to resize (that last bearing is inboard of the flange).

Just filling the oil tank should not have caused oil to leak past the rear main seal. Are you certain it's leaking from the rear main seal? Not from somewhere else?

Stretch32 · 12-14-2022, 02:04 AM

I wasn’t sure if that part of the crank was also undersized and, if it’s not a normal procedure , I doubt Ollie’s would do it. Seeing people discuss “undersized” main seals on turned cranks is what had me slightly confused.

The oil appears to be coming from the transmission bell housing. Since I use Brad Penn and it’s green oil, it’s certainly engine oil. We’re going to pull the engine this weekend and take a look but it’s coming from the the area of the engine were the seal is.

More to follow but thanks for the info so far.

proporsche · proporsche's Garage

what kind of crankshaft seal have you used all brown or Porsche brand or Elring?Also possible your seal spring is off or loose...
Ivan

stownsen914 · 12-14-2022, 04:32 AM

Bummer. Pull it and check the source of the leak. Could also be a defective in incorrect size seal (ID) got passed to you.

pampadori · pampadori's Garage

I've read here on other threads that for this particular seal, only use the Porsche seal unless you want leaks.

proporsche · proporsche's Garage

my favorite seals are Elring ..but i have the good stuff ,old stock, i did see some problems with Elring types newly made...do not like Victor R ..
Ivan

Walt Fricke · 12-14-2022, 06:26 PM

May not be germane, but you can tighten the ID of the seal by removing the garter spring, unscrewing it, snipping off a bit, and putting it back together and on the seal.
Can be tricky to see if a leak is from the seal ID side, or the OD side. But maybe with a seal that leaks even before the engine was running would be easier to differentiate - you should be able to see where it is coming out.

Ollies would never turn the seal surface of the crank, at least not without discussion with you. It isn't a regular wear surface the way the journals and mains are. If there is severe wear on this surface, the cure is to sleeve it.

If a seal is installed a bit crooked, dust will have a wider band to create a bit of wear, leaving a wider wear ring. There is a little bit of leeway in how deep to mount the seal, so sometimes you can install it to miss any existing wear marked part of the crank surface. But leaks from anything like this aren't going to be like what you describe.

Walt Fricke · 06:29 PM

dupe

proporsche · proporsche's Garage

[QUOTE=Walt Fricke;11873217]May not be germane, but you can tighten the ID of the seal by removing the garter spring, unscrewing it, snipping off a bit, and putting it back together and on the seal.
here is a video i made..cut of about 3mm on the female .....

Ivan
https://www.youtube.com/watch?v=Q83YRYcSpDE

HaroldMHedge · HaroldMHedge's Garage

An option that might work to bring the crankshaft back to the original diameter would be to install a shaft repair sleeve.

HaroldMHedge · HaroldMHedge's Garage

An option that might work to bring the crankshaft back to the original diameter would be to install a shaft repair sleeve.

targa72e · 12-17-2022, 11:51 AM

You don't say which year your engine is so this may not work for you. Porsche does make a undersize rear main seal if needed for the 6 bearing crank (2.0-2.7) motors. The standard seal is: Crankshaft Seal (Flywheel) 65 X 85 X 10 mm. The undersize seal is: Crankshaft Seal (Flywheel) (Undersize) 64.5 X 85 X 10 mm part number 90110291100 and is available from our host at the link below.

https://www.pelicanparts.com/More_Info/90110291100.htm?pn=901-102-911-00-OEM&q=90110291100

You might need to measure your sealing surface to see if you need the standard or undersized seal.

Thanks,

john

Fixer · 12-19-2022, 03:01 AM

Run the motor and see if the drip goes away.

I had the same problem, there were a bad batch of RMS out there in the aftermarket.

Good luck

Matt

Stretch32 · 06:04 PM

The engine is a 2.3L (built from a 2.2E) with a 66mm crank. I ordered the Elring seal and will measure the sealing surface, before putting the new seal in, when I take the engine out.

Since I had the engine in, I was going to run it and see if there are any other issues before pulling it to replace the seal. It’s also taken me two years to get to this point so starting it up would be nice even if I know it’s coming right back out.