Top compression ring

[ronrob]

Last try. Does anybody know where I can buy top (chrome) rings for a standard diameter 82.5mm 912 piston. The difficult bit is that I need a 2mm thick ring, as opposed to the standard 1.5mm ring. Thank you in advance for any help.

[Peter Graham]

This is for a 912/616 normally aspirated motor, right? I don't think you will be very happy with a top chrome ring, mostly due to the heat distortion of newer cast iron sleeves or that fact that old sleeves usually cannot be brought back to 'new' tolerance. Of course if you're spending the money for LN Engineering 'Nickies' and JE forged pistons that might be different.

You might try Deves.com/Porsche or Total Seal for something that will work...

Peter

[ronrob]

First off, thanks very much Peter for replying. I am new to 1960 Porsche technology. The car seems to be 912/616 standard in every way EXCEPT for the dimensions of the top groove. The Mahle iron sleeved cylinders and the Mahle pistons have little wear (the car was off the road for maybe 20 years). I bought a set of Mahle rings only to find that the new top ring was 1.5mm thick (standard) while pistons have a 2mm wide groove. In my ignorance I thought that all top rings were chrome.
To keep me right, please tell me which material I should specify when looking for a top ring in this configuration. If necessary, I will have rings made in the UK (although I live in France).
Thanks again.
Ron Brown (ronniebrown7@aol.com)

[Peter Graham]

I suggest you contact one of the companies I listed in my previous post and a third: Hastings. Looking on the chart for Deves, it only shows one set with a 2mm top ring #1369 for 356, 1600 Normal/Super. It is possible that the engine was 'reassembled' with Mahle p&c's which were not original to the 912.

You should be able just to buy a set of 2mm top rings from any of these suppliers; you probably go with iron/ductile iron rings for best sealing.

I am not an expert; just trying to help. I recommend you contact the companies so you can explain your specific application.

Peter

[ronrob]

Perfect reply Peter. I am doing exactly as you suggest. The bores on 2 cylinders are slightly tapered rather than oval so I am tempted to try just new rings.
Sincere thanks for your help. Once everything is back in place I'll post up the results.

Ron

[ronrob]

Just an update on this thread. As Peter suggested, I contacted Total Seal and Deves. Total seal came back with a quote for top rings only (as I wanted) on 1st July and I received them a couple of days ago. I'll fit them and see if a ring change was enough to cut the smoking or whether a complete piston/cylinder job is required. Thanks Peter.