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[Darren65]

Well......seal purchased, engine in, drive around the block???

What's happening?

[jamie]

Seal purchased, engine in. I didn't start it as it was too late and I didn't want to wake the neighbours' kids.

Will fire it up tomorrow morning.

[jamie]

Fired-up engine and pinned it to 2500rpm to continue the cam burn-in. Was feeling pretty cool, so I started to make a video to show the engine sound.

About seven minutes in, I noticed another big puddle of oil under the bellhousing. Exactly the same place as last time.

I dunno.

I'm guessing it's a high-pressure situation in the engine somewhere, and the rear main seal is the weakest point. I don't know the pressure as the 912 only has an 'idiot light' to warn if it gets too low.

I pulled the engine and flywheel (22 minutes this time), shut the garage and walked away. f*** it.



An aside: made these tinware supports last night from stainless.





Leaky seal (brand new, correctly installed):



Mating surface of the flywheel to seal looks OK.

[hot66]

Any crank movement ?

[jamie]

Endfloat or lateral?

I haven't checked either, the engine having new bearings etc. Perhaps I ought to.

[jamie]

On a plus note, the engine sounds fantastic, is epically smooth and very revvy. The throttle response 'snaps' instantly when you crack the throttle. It feels like it will be good once this is sorted...

[DustyM]

I'm not an expert on the 4cyl engines but I wouldn't have thought the oil should pool behind the seal like that is there a drain hole in the case that could be blocked?

[hot66]

Are 912's like vw?

End float should be checked as its a simple one, but that shouldn't cause a leak immdiatly . Was the crank checked

Have you checked the seal against the flywheel

Edit : I imagine it will not be anything with the crank but just something simple,

[Robind]

Can you still talk to the engine builder or are you beyond this with him now??

[Lightweight_911]

Did you use a new (thin metal) 'gasket' between the crank & flywheel ?

[Bruce M]

Maybe worth having the genuine seal, although that one looks decent quality but the sealing lip must be deep set to avoid the radius of the flywheel.

[Andy m.]

From the pictures it looks to me as though the seal isn't in the case far enough, it has to bottom out inside the case bore, same as a vw seal, There's a lip that it butts up to, as yours is fitted currently the sealing lip will be rubbing on the radiused part of the flywheel spigot,
use an old seal to press the new one in with to get it passed the case edge, if you follow my drift,

Cheers

Andy

[KS]

Are you sure that seal is installed correctly? Looks like it's not far enough in to me. Usually flush against the case at least, if not a mill or so inset. That will kill a rear seal in no time as it is not seating against the right part of the flywheel shoulder.

[jamie]

I checked and the seal -appears- to be seated as far into the case as it goes.

Good call on using the old seal though - I'll do this.

Got me wondering if this might be something more sinister, like a crankcase pressure problem. Don't know why it would be, but it's on my mind.

[jamie]

Can you still talk to the engine builder or are you beyond this with him now??

Long gone, I'm sorry to say. He just massively lost his shite with me for the powdercoating thing and generally lower standards of workmanship.

I was initially very upset. Now I don't care at all. This is still a learning process for me and I've never pretended otherwise. It's my car and I work to the standard I work to (even if it does mean installing two leaking main seals).