964 engine reseal - what to replace?

[John McM]

The area around my nose bearing is leaking and the Intermediate shaft cover is weeping in sympathy so I'm beginning a full case split reseal.

The engine was fully rebuilt 12,000 miles ago so I'm expecting the valve guides, bearings etc to be in good shape.

Apart from the obvious gaskets and O-rings what parts are once only use? Piston Rings, bolts?

[Dpmulvan]

What's wrong with the rebuild 12,000 miles ago? Why split the case? I would fix the leaks and put it back in the car unless there's other issues.

[DRACO A5OG]

If like the 3.2 case,

Before you reseal, check the Crank and Case for straightness, checking the case journal seats to make sure they are within spec diameter.

I would also check the cylinder to case deck, make sure that is absolutely flat so it will not promote leaks or worse binding Cams.

When you re-seal, make sure you use the Green viton o-rings, Brown Oil Pump O-rings, and the Black Brown Flywheel and Nose Seals or simply buy the Wrightwood Racing Package via our host. On that note, when you split the case, look at the o-ring closely at the #8 to see if it got pinched and before you remove the perimeter nuts near the #8 and IMS, check the torque spec with a dependable torque wrench.

I like to use a weight and fine tune the wrench if it is adjustable.

Break a leg brother!

[John McM]

Originally Posted by Dpmulvan

What's wrong with the rebuild 12,000 miles ago? Why split the case? I would fix the leaks and put it back in the car unless there's other issues.

The nose bearing area is leaking significant amounts of oil (4 litres in 2,000km). This is after I fitted a Tom Amon collar to try and fix what in hindsight has been a problem since the rebuild was completed.

The only option left for a long term fix is to open the case and correctly seal the area.

[John McM]

Originally Posted by DRACO A5OG

If like the 3.2 case,

Before you reseal, check the Crank and Case for straightness, checking the case journal seats to make sure they are within spec diameter.

I would also check the cylinder to case deck, make sure that is absolutely flat so it will not promote leaks or worse binding Cams.

When you re-seal, make sure you use the Green viton o-rings, Brown Oil Pump O-rings, and the Black Brown Flywheel and Nose Seals or simply buy the Wrightwood Racing Package via our host. On that note, when you split the case, look at the o-ring closely at the #8 to see if it got pinched and before you remove the perimeter nuts near the #8 and IMS, check the torque spec with a dependable torque wrench.

I like to use a weight and fine tune the wrench if it is adjustable.

Break a leg brother!

Thanks for the advice. I've rung the machine shop that specialises in these engines and they've confirmed I can just walk in with the parts and a list of checks.

[DRACO A5OG]

^^^, Outstanding :-D

[mikedsilva]

4 litres in 2000 kms! ****.

[John McM]

Originally Posted by mikedsilva

4 litres in 2000 kms! ****.

Yes, my car washing started with a degreaser. It was unsupportable long term even if I have to do a complete reseal

[John McM]

Heat exchangers successfully removed. Down to the nitty gritty. As per the original question, do I need new rings etc for a simple reseal?

[John McM]

3 exhaust studs to be replaced but otherwise happy that job is over.

[mikedsilva]

Exhaust studs can be a pain... but good that you got them off.

[RedCoupe]

Originally Posted by John McM

Heat exchangers successfully removed. Down to the nitty gritty. As per the original question, do I need new rings etc for a simple reseal?

With very low miles since the last rebuild, I wouldn't think your engine would need new piston rings. But, did you do a compression or leak down test before you tore the engine apart? Also, do the cylinders look good? No scratches or pitting of the hard coating? I would also remove a few valves from the heads to make sure that the valves and the seats don't have any pits or carbon buildup. You can also make sure that the valves aren't loose in the guides and replace the stem seals while you're at it.

[Jeff Alton]

John McM,

Check your rebuild invoice for a #8 bearing. It is not part of the "main bearing set" that may be listed. If you had a complete rebuild (top and bottom) it should not be leaking like that after 12K miles.

When did you notice some signs of leakage? Right away, a short while after rebuild or???

Let us know please.

cheers

[John McM]

Originally Posted by mikedsilva

Exhaust studs can be a pain... but good that you got them off.

It was a nervous moment as I put torque on the various nuts. PB blaster and Map torch heat helped. Evidently the studs gave up before the nuts in 3 cases but they're easy to replace. All new nuts and lots of anti sieze when these go back on.

[John McM]

Originally Posted by RedCoupe

With very low miles since the last rebuild, I wouldn't think your engine would need new piston rings. But, did you do a compression or leak down test before you tore the engine apart? Also, do the cylinders look good? No scratches or pitting of the hard coating? I would also remove a few valves from the heads to make sure that the valves and the seats don't have any pits or carbon buildup. You can also make sure that the valves aren't loose in the guides and replace the stem seals while you're at it.

No tests beforehand. Right now all I've seen are the back sides of the valve. All inlet valves look perfect. One exhaust valve (cylinder 5) has signs of oil coating. One ceramic head liner is cracked. No chunks missing. One spark plug on cylinder two is slightly darker. The rest look like this pic.

[John McM]

Inlet valve

[John McM]

Originally Posted by Jeff Alton

John McM,

Check your rebuild invoice for a #8 bearing. It is not part of the "main bearing set" that may be listed. If you had a complete rebuild (top and bottom) it should not be leaking like that after 12K miles.

When did you notice some signs of leakage? Right away, a short while after rebuild or???

Let us know please.

cheers

Definitely no receipt for #8. It has leaked since rebuild, it's just taken me this long to realise what's wrong and how wrong it is. The rebuilder was an OPC. Understandlibly they're not jumping to fix it considering it's been four years since the rebuild. I've shown time stamped pics of the tail soon after the rebuild. I'm hoping that the bearing will clearly show what's wrong when I split the case. If it's obvious then I'll be giving them a visit to see what can be done.

[mikedsilva]

Originally Posted by John McM

Definitely no receipt for #8. It has leaked since rebuild, it's just taken me this long to realise what's wrong and how wrong it is. The rebuilder was an OPC. Understandlibly they're not jumping to fix it considering it's been four years since the rebuild. I've shown time stamped pics of the tail soon after the rebuild. I'm hoping that the bearing will clearly show what's wrong when I split the case. If it's obvious then I'll be giving them a visit to see what can be done.

Good luck!

Interestingly, when I ordered a set of genuine bearings for my case here in Brisbane from the local porsche centre, it included the number 8 bearing. I was fully expecting to have to shell out a few hundred extra but got lucky for once .

[jamesjedi]

"Before you reseal, check the Crank and Case for straightness, checking the case journal seats to make sure they are within spec diameter.

I would also check the cylinder to case deck, make sure that is absolutely flat so it will not promote leaks or worse binding Cams"

DRACO;

I have been looking for information on how these procedures are done. Is it in the factory manual?

[Jeff Alton]

A straight edge placed over the spigots will tell you if the case bores are true and flat.