Carrera 3.2 IMS cover oil leak

mikedsilva · 09:30 PM

Curious if anyone has ever out together a motor to have this cover leak? The 3.2 has the plate, o-ring and 2 offset bolts to hold it down.
The 964 I have done have the same arrangement and not leaked.. I just used molykote on the o rings to install.

On this 3.2, I did the same, but after a test drive, the next morning there were some drips.

The case halves are perfectly aligned. The inside surface in which the o-ring sits feels like it is nice and smooth along the parting surface. The cover plate didn't have any obvious nicks or scratches where the o-ring is located.

Thinking to just clean it all out, and install the o-ring with some 1104?

Any other suggestions or am I the only one to experience this?

Cheers.

dannobee · 10-03-2021, 07:03 AM

Threebond cures a lot of sins...

mikedsilva · 09:35 PM

Quote:

Originally Posted by dannobee

Threebond cures a lot of sins...

turns out it's the crank pulley seal leaking.. problem is, it's new.
I figured I must have damaged during install... so I removed it for inspection.

Seal 'looks' fine to the eye.
Nose of the crankshaft also looks fine.

Any ideas?

cgarr · cgarr's Garage

How was the nose bearing fit? any marks on the crank where the seal rides?

mikedsilva · 10-04-2021, 02:48 AM

Quote:

Originally Posted by cgarr

How was the nose bearing fit? any marks on the crank where the seal rides?

It is actually pretty clean. I will have a closer look tomorrow.
Really not sure how I stuffed this up....

Jeff Alton · 10-08-2021, 07:54 PM

Mike,

I trust you installed the pulley seal after assembly. It could be the O-ring on the #8 bearing, which needs some extra help during assembly. Does not mean you made any mistakes. You are not dealing with a brand new case and crank...

Cheers

dannobee · 10-09-2021, 08:45 AM

Jeff brings up a good point. It could be that the #8 bearing bore isn't quite right. Or there's sealer stuck in the drain-back groove. Of all of the machining processes, it seems like for whatever reason, the #8 often turns out goofy or moves around over time. I think we've all measured them and went, "hmmmm..."

If it turns out that it's leaking between the #8 bearing and the case, I think Henry has a ring kit available (Tom Amon collar) to eliminate the leak without having to split the case.

Dominik 930 · Dominik 930's Garage

i bought some of these green sealing rings from porsche because i always had a slight sweat on this cover. i haven't had any success with the original porsche seals. I then had thicker sealing rings made for me and installed them and since then there have been no more problems. the lid is tight.
By the way, friends of mine also have leaks on this lid. the newly made sealing ring is larger on the outside and larger on the inside.

KTL · 10-11-2021, 02:33 PM

Agreed with the other guys that I too wouldn't just jump to the conclusion that the leak you're seeing is the shaft seal. That #8 bearing insert is notorous for weeping (or leaking) and causing folks to think it's the seal. I know that's not the belief you want to hear, since the most obvious fix is to split the case and inspect the o-ring.

This type of leak is why the suggestion of using sealant on the #8 bearing insert o-ring is so often recommended. The sealant adds a level of additional sealing ability to the ring and also gives the ring some lubrication to move a little bit when the case halves are bolted together and the squish occurs.

My one concern has always been to be careful with avoiding excessive sealant here, because you don't want it to squish too much and get into the important oiling hole in the case. That oiling hole not only feeds the #8 bearing, but also that end of the crank. Let's not forget that the crank is fed from the engine case, from the ends. #8 at the pulley end and #1 at the flywheel end are the sole locations of delivering oil INTO the crankshaft for feeding your rod bearings!

mikedsilva · 10-13-2021, 05:05 AM

Sorry to have not updated this.
It was in fact the pulley oil seal. I removed it, fitted a new oil seal, and it's bone dry. I must have damaged it during assembly.. weird as I never had done this before.

To the eye (and mag glass), the removed seal looked perfect. So I still don't know why it leaked.
But all is good now.

KTL · 10-13-2021, 01:49 PM

Great to hear I was completely wrong and a new seal fixed it. CONGRATS!

Walt Fricke · 10-13-2021, 09:37 PM

This is such a mixed emotions thing. Happy the problem is gone. But very puzzled as to why what was there failed. So you didn't learn anything, and have no reason to believe it won't happen again.

Been there.

mikedsilva · 10-14-2021, 07:11 AM

Quote:

Originally Posted by KTL

Great to hear I was completely wrong and a new seal fixed it. CONGRATS!

kind of a hollow victory...

mikedsilva · 10-14-2021, 07:12 AM

Quote:

Originally Posted by Walt Fricke

This is such a mixed emotions thing. Happy the problem is gone. But very puzzled as to why what was there failed. So you didn't learn anything, and have no reason to believe it won't happen again.

Been there.

Spot on!

KTL · 10-14-2021, 07:36 AM

Maybe the seal lip was folded back during installation? Not trying to imply you’d install a seal poorly. Just happens sometimes.

For example, the factory tool for the big seal at the flywheel end has a very thin sleeve/tube that is used for just that reason. You press the seal in place, remove the press assembly and then gently insert the sleeve to ensure the seal surface is uniformly set around the crankshaft flange. A lot of people have rolled their eyes at the suggestion of using this press tool assembly. But don’t knock it until you’ve tried it. It works fantastically