I think I have a rear sealing crankshaft leak after the engine rebuild of my Porsche 944 S2. Propably because of a groove, caused by the previous seal. Does anyone had the same problem? Is there a solution? Can I mount a sleeve over the groove in the crankshaft?

 

Thats one hell of a nasty groove
yes, speedi-sleeves are available

 

Purchase a new seal from Linsey Racing and talk with Mike. He will tell you how to make the spring shorter so there is more force on the seal lip to compensate for the groove in the crankshaft.

 

There's no compensating for that groove.

The groove is cause by dirt/grit acting as a cutting agent.

I would go with the sleeve, or at a minimum, make accurate measurements and position the depth of the seal differently so the lip and garter spring apply pressure in a slightly different area of the crankshaft.

T

 

In regards to seal depth, I just dealt with this when installing my rear main seal (though I didn't have any scoring). Some instructions say to flush the seal with the case, as in the pics above, but others say to to countersink the seal until it's seated fully in the recess. I went with the latter because it made sense to me, but we'll see when it comes time to fire up the engine. But certainly having the seal at a different depth than that groove might help.

 

I agree with T's assessment

 

Depth-wise (further than flush) the only thing you usually have to be concerned with is a drainback path.
Oil gets by the rear main bearing, thus the necessity for the seal...., but between these two components (not just in this engine) there is a drainback, sometimes as small as a 8mm hole.
As long as the outer metal clad part of the seal doesn't block this oil route, further than flush is fine.

T

 

Before Viton and better quality rubber hybrids, some transmission front seals would actually become soft from a reaction with......, yep, transmission fluid.
Also, on drag racing and high revving American automatics, the amount of oil that passes the front bushing is more than can drain back, which makes the seal lip flip outwards or blows the front seal out.
Old trick was to unhook the garter spring, tighten by shortening and rehooking (just coils of a soft wire spring), loctite the seal outer diameter and drill/tap the pump face so #6 screw heads would overhang the seal flange.
For drags, works fine (short engine duration) but if you tighten a garter spring beyond designer's intention, the seal lip can burn.

T

 

LOL, where did you learn all this crap?! And I mean this in the best way; I always love reading your posts.

 

Thanks to all for the very interesting information!!!
I will measure the crank when the flywheel is off and try to find the right sleeve.
The protective plate under the flywheel was gone. This propably let dirt reach the rear sealing.

 

skf has the measurements for the sleeves in their catalog. http://www.skf.com/binary/30-128020/...edi-Sleeve.pdf

 

30 years in automatic transmission business, 10 years building winning race cars, 10 years government job with equipment ranging from massive pumper fire trucks, dirt moving eq, street sweepers, abused police units, etc., etc. some of the experience with overlap.

The tag on my shirts where it usually says "fruit of the loom", reads "been there done that"....

And thanks,

T

 

The VR rms will not seal unless it is in past flush. There is a notch at the bottom of the rms "hole" that is used to pry the old seal out. The rubber part (sealing part) of a VR rms will not seal that notch unless it is driven in past flush. If you had an elring rms in there before and it was flush (can do because the sealing rubber goes all the way in) perhaps a VR seal put in past flush will position the inner seal away from that groove.

 

Hmm you might be right. Here is a picture before the rebuild. The seal was indeed mounted past flush. If the leak comes from that notch, I will see it during inspection soon.

 

I finally found some time to replace the crankshaft seal.
Picture of the leaking seal:


I inspected the dissambled seal. Couldn't find any damage.
I replaced the seal and pushed the new one 2mm deeper.


Unfortunately it did not help. The seal is leaking as much as it did before.
Think I need to find a sleeve. Wish I took the dimension of the crank