John McM

Pulley and air con support removed. Not as wet as I thought it would be

John McM

Hairline crack in JB Weld around the Tom Amon collar but the collar is only wet with oil at the base. If it's leaking higher on the collar I would have expected more oil up there

John McM

IMS cover is wet but that could just be oil from the nose bearing

John McM

The perfect fix would be to split the case, replace the nose o-ring and the IMS o-ring. A few weeks of my life and $$$ in parts. Instead I'm going to clean and sand the JB weld then coat it with CRC Red 340. I will replace the IMS O-ring and seal it with Threebond 1211.

prschmn

When you say it was "completely" rebuilt that did include splitting the case right?
That leak is absolutely caused by a bad o-ring on the number 8 main and or someone
used way to much sealant and plugged the groove that relieves pressure from building up
behind the lip seal. It's the OD of the #8 bearing that aligns the case halves.
I have never had it happen in any engine I've built.

fiskarflugen

I could be wrong, but I believe the jb weld goes on first then the ring over the weld? It's how I did mine fwiw, still dry after 15k.

John McM

Yes, the case was split. Done by the local OPC. The pic with the RTV was their work.

John McM

Yes, that's how I did it.

John McM

The back of the pulley is dry. After a good nights sleep I looked at the photos again. I think the oil coming out of the area circled in green.

John McM

Your post started me thinking. Is it normal to put RTV in this area during a full rebuild? If not, then what I'm looking at is possibly the engine builder at an OPC trying to fix a leak found after the rebuild without resplitting the case. I have asked them to comment. A bit hard for everyone considering the rebuild was 3.5 years ago but still the evidence was there to see and it's not something an owner could look at easily.

John McM

I wiped the pulley and intermediate shaft area this morning then returned to it after work. I was pleased to see a leak around the intermediate shaft cover, and quite a large one considering the engine hasn't been started in four days. I will put a new o ring on and seal the cover with Threebond 1211. If this turns out to be the largest leak then I will use Red 340 on top of the Tom Amon collar around the nose bearing and call this job done.

Rocket Rob

Glad to see you are isolating where the leak is. Keep us posted.

John McM

More confirmation this morning. Over 11 hours the leak was large enough to run down the case join and drip.

Please note that Threebond 1211 is not needed for the intermediate shaft cover in a 964. It was used in older 911 versions with gaskets. My error. However given the leaks I will be sealing the exterior of the cover with the Red Gasket 340.

cscrogham

You are doing a great job there! It is very difficult to explain to customers what an immense pita this job is to replace a few $2 gaskets and seals.

-nick

Great photos John. I'm following this too. I haven't taken the time to trace if my leak is from the crank or the ims, but my only engine leak is also from this area. I replaced the crank seal and the ims o-ring about 2 years ago. Mine seems to weep more when the outside temp is very cold (~freezing). I Just smeared some dc50 on the ims o-ring when I replaced it.

There are some pros over at the pelican engine rebuilding forum who may be worth checking with for ideas. I believe it was Henry at Supertec who told me that the 3.6's practically leaked as soon as the factory filled them with oil.