Crankcase damage

[jakev]

The engine was running and then developed an oil leak. After removing the engine from the car, removed the transmission and found the flywheel bolts very loose. Removed the flywheel and found the seal damaged. Also found the crankcase at the seal is damaged. That's as far as I've gone. Is the crankcase repairable?

[Dpmulvan]

Yes.

[john walker's workshop]

Where is the damage, unless i'm blind...? The seal isn't in all the way. Is there any radial play in the crank? I remember one 2.7 years ago that kept blowing out seals, because the main bearing bore was vastly worn out and you could move the flywheel about 10mm sideways.

[stownsen914]

Was going to ask where the crankcase damage is, I don't see it either.

Make sure the crankshaft and flywheel mating surfaces aren't buggered from the bolts being loose. Hopefully the flywheel would be the sacrificial part in case there is any damage.

[mikedsilva]

Is it just me, or are a couple of the threaded holes in the crankshaft, not threaded?
I can see the splits in the seal.. wonder why they didn't install it all the way in..

[jakev]

This is the 3rd seal in this engine. It did have some crankcase damage once with axial movement of the crankshaft, but I sent it to Ollie's for repair and it had no axial movement when I re-assembled. No lateral movement either. Can the clutch assembly pull on the crankshaft and cause the seal to pop out? It's a 915 transmission.

[stownsen914]

A loose flywheel could cause some serious vibrations in this area. Not sure if that would cause a seal to move in its bore. Is the seal tight in there?

[safe]

Crankcase pressure?
There is an oil drain passage behind the seal, is it open or plugged?

[safe]

Originally Posted by mikedsilva

Is it just me, or are a couple of the threaded holes in the crankshaft, not threaded?

Might be shadows, but the 9 o'clock hole looks thread-less. But I don't think anyone would miss that during assembly !

[mikedsilva]

Originally Posted by jakev

This is the 3rd seal in this engine. It did have some crankcase damage once with axial movement of the crankshaft, but I sent it to Ollie's for repair and it had no axial movement when I re-assembled. No lateral movement either. Can the clutch assembly pull on the crankshaft and cause the seal to pop out? It's a 915 transmission.

OK, when you reassembled it last, what torque spec diid you use for your flywheel bolts? Seems odd that they would be "very loose".

Also, can you confirm the condition of the threads in the holes?

[jakev]

I torqued the bolts to 150 nm. I can't remember if I used locktite. No evidence. The workshop manual doesn't mention it. I will have to check if there is a plugged oil port. The workshop manual doesn't show one. All the bores on the crankshaft end are threaded. There is a piece of metal at the 5 PM position resting on a fin. I have no idea where it came from. The manual says to use a sealant, but doesn't specify. What is recommended?

[Dpmulvan]

Originally Posted by jakev

I torqued the bolts to 150 nm. I can't remember if I used locktite. No evidence. The workshop manual doesn't mention it. I will have to check if there is a plugged oil port. The workshop manual doesn't show one. All the bores on the crankshaft end are threaded. There is a piece of metal at the 5 PM position resting on a fin. I have no idea where it came from. The manual says to use a sealant, but doesn't specify. What is recommended?

Seal is really torn up I don’t get how that happened or the loose flywheel bolts. Seal should be installed dry. Why don’t you pull seal and take some more pics.

[Jeff Alton]

There is a slightly oversized seal available from porsche as well for the 2.7

[porschedude996]

Originally Posted by Jeff Alton

There is a slightly oversized seal available from porsche as well for the 2.7

I wouldn’t think so. Maybe a RTV “Adhesive” and extremely clean surfaces. Being from the aerospace industry for many years, I know there are better RTV’s that are better than the auto parts store.

Try something like this:

https://www.momentive.com/en-us/categories/adhesives-and-sealants/rtv157-and-rtv159-silicone-adhesive


It looks like the seal was never installed deep enough or it slid out. CLEAN CLEAN CLEAN is my suggestion.

[michaelmount123]

Here's the deal on loose flywheels which are all too common, especially on the 6 bolt crankshafts:

When Loctite is used on the bolt threads, screwing them in pushes some of the Loctite between the FW and the crankshaft flange. Once torqued, the Loctite prevents a solid metal to metal joint and the FW will loosen in time - particularly in a performance application. The solution is to carefully clean both the FW back surface and the crank flange, then put one drop of Loctite (red) in the female threads of the crankshaft. Fit the FW, and torque the bolts in an alternating pattern in several stages to 110 ft. lbs. I've never had a FW loosen over many years and many 8000+RPM engines.

The other issues related to case repair have been addressed above. The seal should not push out if the engine is relatively fresh and the breather is unobstructed.

[porschedude996]

Originally Posted by michaelmount123

Here's the deal on loose flywheels which are all too common, especially on the 6 bolt crankshafts:

When Loctite is used on the bolt threads, screwing them in pushes some of the Loctite between the FW and the crankshaft flange. Once torqued, the Loctite prevents a solid metal to metal joint and the FW will loosen in time - particularly in a performance application. The solution is to carefully clean both the FW back surface and the crank flange, then put one drop of Loctite (red) in the female threads of the crankshaft. Fit the FW, and torque the bolts in an alternating pattern in several stages to 110 ft. lbs. I've never had a FW loosen over many years and many 8000+RPM engines.

The other issues related to case repair have been addressed above. The seal should not push out if the engine is relatively fresh and the breather is unobstructed.

I’d like to see a scientific review of this.

[mikedsilva]

Originally Posted by jakev

I torqued the bolts to 150 nm. I can't remember if I used locktite. No evidence. The workshop manual doesn't mention it. I will have to check if there is a plugged oil port. The workshop manual doesn't show one. All the bores on the crankshaft end are threaded. There is a piece of metal at the 5 PM position resting on a fin. I have no idea where it came from. The manual says to use a sealant, but doesn't specify. What is recommended?

And you used the large 6-hole washer on the flywheel, for the bolts?

[stownsen914]

Take Michael Mount's advice on the bolts, I thought the same thing.

Curious to know more about the seal.

[jakev]

Attached is another picture of the seal. It appears to have moved ccw about 15 degrees. I can see the port for the drain of the oil behind the seal. What should I be checking for now?

[jakev]

This time with the photos