No. Cylinder bores and pistons come in "0", "1", and '2" sizes that vary tiny amounts, to enable Porsche to control piston to wall clearance very accurately.

 

Thinking about what the cost of shipping a complete engine (or a short block) around the country, I'd really suggest that you get one oversize piston and have a machinist bore, hone, and prepare that one cylinder. Deck the block, when finished.

Done.

 

 

Very doubtful that the gouge is too deep for the oversize piston.

If your machinist has a Sunnen, the pieces required bore and finish the cylinder are not that expensive. There are complete instructions in the Porsche Workshop Manual on how to do the procedure. It's not rocket science. There's also a 100 page long technical book, from Kolbenschmidt that tells everything there is to know about sleeves and boring of the block, if you need more information.

Steel sleeves would mean that you'd have to come up with a custom piston for a steel sleeve that weighed the same as a stock piston....not likely.

I now stock Alusil sleeves from Kolbenschmit for these engines. Machine work required. The sleeve is actually "cheaper" than an oversize piston, so that might be an idea. (I'm certain that a "perfect" standard piston would be easy to find.....Mark will have one of those.) I'm putting a sleeve in a GTS block, to save the engine, as we speak. Note that a sleeve would also repair that damage to the top of that one cylinder....

Anything you do to that engine will require complete disassembly (pistons out, crankshaft out, etc.), so pulling another piston out isn't going to be an issue.....

 

I personally repaired a block (casting material that never left the block until I removed it ) with some white metal brazing rod. seen here: https://rennlist.com/forums/928-foru...-on-928-a.html

I'll see how it does after I put the engine together, the damage was outside of the fire ring lands so repairing it doesn't require absolute perfection like your damage will.

If your machinist has the correct tools to do the repairs do what Greg says. It'll save you a lot of headache in the future. A fresh alusil sleeve wouldn't be a bad thing

 

Running a stock Ferro-coated piston in a cast iron sleeve must be possible. I have not tested, anyone having the experience?
Iron-coated piston skirts (Ferrocoat®) guarantee reliable operation when used in aluminium silicon cylinder surfaces (Alusil®).
Åke

 

 

Some interesting reading on the Nikasil insert procedures.

http://www.google.com/url?sa=t&rct=j...vbagIbKRKC2T3t

 

Nicasil is a completely different surface treatment than Alusil.

Different pistons, different rings, etc.

 

My machinist thinks that a Ferro-coated piston would be fine in a cast iron sleeve. He claims that most of the older aluminum pistons came coated with iron.

My education tells me that similar metals sliding against each other will gall....

I'm not willing to spend the time to experiment.

 

 

​​​​​This would be great, of it was a "for certain, long time" approach.

I've seen some very nasty bores and pistons in many 928 engines that ran.

The proof, for me, needs to be absolutely conclusive....everything I build I expect to last as long as it did, originally.

Has anyone taken one of those engines apart to see how the pistone and bores are performing?

 

 

Greg - can you point me to the Kolbenschmit document you reference, I'd like to read it - My google search did not result in any hits. Do you happen to know if they also have Alusil sleeves for Cayenne applications?

Matt