Can I reuse this Cyl??

euro911sc · euro911sc's Garage

The inside surface is perfect as are the cyl walls. I can still see cross hatching. But, the outer lip is scratched/scared as shown below:

How it happened, I do not know. The seal ring was not intact on that side so I suppose it may have been the culprit, but all head studs were tight and intact on this cyl...

-Michael

MBruns · 03-23-2006, 11:14 AM

JUNK, the head seal ring came apart and danced between the seal surface, either broken cyl stud or studs or loose heads. those wont be hard to find as singles.
Mike Bruns JBRacing.com

andrew15 · 03-23-2006, 11:23 AM

If this is for your 82 SC, I have a NOS Mahle nikasil cylinder available. I'm out of town on business right now, so I can't check the cylinder height group, but will be back on Saturday and can let you know then if interested.
Regards,
Andrew M

euro911sc · euro911sc's Garage

Thanks guys! Another office paperweigt to add to my growing collection!

I guess I better double check all the rest just in case...

*sigh*

2 are toast
1 is questionable
3 are good

So... can they be machined back? or is this simply a replacement thing... ?

-Michael

Eagledriver · 03-23-2006, 07:35 PM

Michael,

The safest thing would be to replace them. If they are Alusil then I wouldn't even think about reusing them. If they are Nickasil I'd be tempted to try them but you are taking a risk. My theory would be that if the groove for the CE ring is still intact enough to contain the ring and the inner surface is good they should seal. If the seal is so poor that it relies on the outer surface after the CE ring then the seal is not very good to start with. I suspect that 90 percent of the sealing is done with the inner surface and the CE ring.

-Andy

Eagledriver · 03-23-2006, 07:37 PM

Of course my car is a race car and I seem to take the engine apart every couple of years anyway.

-Andy

euro911sc · euro911sc's Garage

Andy-

Thats what I was thinking, but now I'm not so sure. Theoretically, the sealing is done by the ring with the grove it sits in acting as the initial stop gap and primary seal protector. I used to design similar metalic sealing rings in a past life and we never looked to the outer section for much sealing, but I only lasted there 6 months

too boring... so what so I know

They are nickies so I can re-use if all other things are good.

It looks like the top of the inner surface is plated though so I suppose I cant simply throw them in a mill or lapping machine, shave off the tops, and slap in a bigger copper gasket? That's what I had in mind before Mike said they are junk...

That's what I was thinking anyway... now... 3.2 SS on CIS anyone? I can hear the words now... "It's me or yur damn motor! Now which is it?!?!"

-Michael

Eagledriver · 03-24-2006, 09:07 PM

I don't think the tops are plated. Maybe they are incidently plated because of the Nickasil treatment, but I don't think they are plated on purpose. How deep are the scars?

I once had a set of 3.2 cylinders machined for a CE ring (the 3.2 didn't have a sealing ring). Ted Robinson did the machining for me. I'm sure he could take some metal off the tops and deepen the groove to match. I'd have him do all 6 the same. If it can be done taking off a small amount, you could use the thicker base gaskets to get the deck height back. Give Ted a call: 408-747-0728. Tell him Andy Simpkinson recommended him.

Might cost as much as a used set of cylinders though.

-Andy

Henry Schmidt · Henry Schmidt's Garage

The cylinder is not useable.

The cause of the damage is loose head nut. Generally the head nuts are loose do to broken Dilivar stud.
The scarring is cause by the CE ring getting trapped between the head and the cylinder. The CE ring is a spring wrapped with aluminum. The steel spring causes the damage in the picture.

As for sealing, the CE ring is designed to seal oil only, not compression.
As the engine cools oil from the cylinders leaks out causing to area around the head to become wet.

Porsche finally decided that the CE ring did not do what they had hoped. In following years they did away with it altogether.

andrew15 · 03-25-2006, 03:53 PM

I was just thinikng of something - I have a set of 3 used Mahle nikasil cylinders from this thread :

Are these cylinders junk?

Some damage near the bottom (as shown in the thread), but they might just be the ticket for an economical repair.

Andrew M

euro911sc · euro911sc's Garage

*sigh*

ok I give

they are toast. Corresponding damage to the heads can be machined though, correct?

Andrew, what height group are yours? I'll also be considering a jump to 3.2 ... hrmnnnnnn

-michael

andrew15 · 03-26-2006, 05:28 PM

I just checked and all 3 of mine are cylinder height group 6 - let me know if that would work for you.

Regards,
Andrew M

ChrisBennet · ChrisBennet's Garage

Quote:

Originally posted by euro911sc
That's what I was thinking anyway... now... 3.2 SS on CIS anyone? I can hear the words now... "It's me or yur damn motor! Now which is it?!?!"

-Michael

Gee honey, I'm really going to miss you...

-Chris

euro911sc · euro911sc's Garage

Gee thanks Chris "It's not my car..." Bennet! I'll pass on your advice to my wife! Remember, she knows where you live!

-michael