Successful #8 Bearing Oil Leak Fix

[Fishcop]

Hi Guys

I built my engine 5 years ago, but screwed up the #8 bearing (no sealant) when I put the cases together. It was leak free for about 3 months, but after that it's bled oil ever since. Recently it became worse and I felt it had become unacceptable. The repair normally requires the case to be split...

I thought some of you may be interested in my successful fix of a leaking #8 bearing - the O ring, not the pulley seal. It's not my idea, I pinched off a thread I found here which mentioned Tom Amon as the 'brain' behind it.

It involves spinning up an alloy ring that has an interference fit around the #8 bearing which protrudes about 10mm out from the case, I also added a couple of set screws as an added measure.

Prior to pushing the ring on, I applied my chosen sealant... there's a lot of opinion ranging from epoxy, Dow Corning 730, and a few loctite and permatex products. I decided I did want something that could could flex so I went with Sikkaflex marine grade polyurethane in black. This stuff is messy, but sticks like ***** to a blanket and sets to a truly robust flexible and oil impervious medium. The ring is heated and then pushed on so that the sealant spills a bead out and totally fills the case seam and circumference of the #8 bearing. I then tweaked up the grub/set screws. After 48 hours of setting time I cranked up the engine and got it to operating temps...

So two weeks later, not a drop of oil can be seen. I'm really hopeful that this has does the trick!

Also, I found this can be done with just a partial engine drop and you can leave all the oil lines, CV, wires connected.









I hope this is searchable for anyone else that gets stuck for a fix on this problem and is of some use...

Cheers

[bkreigsr]

nice one
I went through this with my 73 after my first rebuild. I was told it leaked because I did put sealant on the bearing during assembly. Go figure.
No quick fixes I tried worked for any amount of time, and eventually , after my son missed a shift on the track, the seal let go completely and it was time for rebuild #2.
yours looks good
Bill K

oh, yeah, where's the screws?

[signature65]

You may be onto something.....making these rings for profit.

[Fishcop]

I'm just happy to offer some ideas for other owners... too much on to be trying to make a profit!

[OZCarrera3]

Damn! Wish I had known about that fix 5 years ago!

I had a similar leak and the subsequent investigation led me to a "while you're in there" project to replace the bearing and seal that cost me the best part of $10k (a full rebuild with new P & Cs). Although someone had already had a go by just whacking a heap of liquid metal around the bearing case. The engine does look and go very though now as a result.

Good job John.

[Alan L]

Well, I think that answers a Q I was about to post.
Can you change either end crank seals without splitting case. I have a friends 2.7 on bench at moment doing few tidy up jobs. If it was possible to insert new seals either end, I would.
I did put new ones in my 3.0, but the case was split. I followed Waynes recipie (sealant) - no leaks so far (3 yrs).
Regards
Alan

[Fishcop]

Alan, the rear main seal and the front pullet seals can both definitely be changed without splitting the case. My leak is from the o ring seal around the outside of #8 bearing (and normally requires the case to be split to fix), the pulley seal is on the inside of the bearing and designed to be reasonably easy to change.

I recall your troubles Sheldon. I didn't realise the trigger was this seal. Coming to Lakeside next month?

[Alan L]

Well, that is comforting, to know you dont have to split the case for those seals.
I am still a bit in the dark on the grubscrew thing too.
A sketch if not a pic might help understand what was done here - which looks pretty useful Anything that avoids spliting the case is useful.
Alan

[bcgreen]

Is there a similar product here on the west coast for 'Sikkaflex marine grade polyurethane'?
Do you have to heat up the ring?

[creaturecat]

Originally Posted by signature65

You may be onto something.....making these rings for profit.

Tom Amon sells them. No?

[bcgreen]

Curious, if everyone who went this route to fix their leak, how's everything holding up?
What was your most successful sealant?

[john walker's workshop]

sikaflex rocks!

[kugelfischer]

Yep, Tom sells these.
FOR SALE - PORSCHE PARTS AND MOTORS - Welcome to Mobile Works West!

FWIW, he installed one on my engine.... And it still leaks

[creaturecat]

Originally Posted by john walker's workshop

sikaflex rocks!

Have you tried used the ring method, with sikaflex, John?
If so, what was your success ratio?
Thanks in advance.

[bcgreen]

I talked to some of the people who went this route and a few were successful and most still had a leak but somewhat less. I even talked to the guy who did a youtube with Tom Amon, and he said his vehicle still leaks.

[strofka]

Where can I get one of those rings?

[zippy_gg]

Originally Posted by strofka

Where can I get one of those rings?

See post 13: FOR SALE - PORSCHE PARTS AND MOTORS - Welcome to Mobile Works West!

[bamboo sc]

Another way to seal the # 8 bearing.
I have done this 3 times before, once with the epoxy, two with oil resistant sealers.
Then , I had this idea.
A silicone "washer" tightly pressed against the housing, with a fixture.
Finally no leak. 82 911sc.
A pic

[bamboo sc]

Bump for perm fix

[Dave Kost]

Tell us more.

Where did you get the washer?