Ring sets
 

Just checking to make sure. My mechanic friend who is working with me to o/h my 87 Carrera sent me home with the ring set to check the ring end gaps. Before I started to rip into the packages I had a mind interuption.

The ring set I have is Goetze 08320900-10. They are to go into Kolbenschmitt Niksil cylinders. The part number in the Dempsey book have a part number for Mahle and one for Kolb.. which are different. Mahle pn is 930-198-986-00 and Kolb.. is same number but 01. Something tells me you can't use a Mahle ringset in a Kolb.. cylinder, but I don't know if that is correct. I don't have a cross reference for the Goetze rings. Is the number above (08202900-10) the proper pn for Kolb.. cylinders.?

Read on this post is incorrect. I correct myself below.

I think this has come up before and the answer was that they are the same replacements for each type. The differences between sets have to do with the size of the rings ie. the width of the rings (1.5mm, 1.75mm, 2.0mm, etc). You can measure the piston ring lands to see which rings you need and the package will list the sizes that are in it. Please post your results. The set I got from Goetz had bigger end gaps than my used set.


-Andy

Ummmm.. will do tomorrow. Thanks for the reply.

The ring types (material) are different between the K/S "allusil" and Mahle "nickies". They are made of different materials and are not interchangeable. I believe the important differential is allusil vs nickisil as there may be some cross manufacturing.

mm readings for new vs old rings

New (niksil)
R1 .146
R2 .171
R3 .347

Old (from alyusil)
R1 .146
R2 .171
R3 .346

Identical to my old eyes.

note on box.
pn 08-320900-10
95 X 1.5 + 1.75 + 35mm STD
Goetze

08-320900-10 are the rings for allusil cylinders which are typical of K/S manufacturing. This is the same set that I used on my re-ring ('83 K/S allusil). These are not for Nikasil cylinders (typically Mahle).

According to my mechanic, whom I trust very much, your information is not correct. He is using the latest PET rev 194. I would like to sugar coat my response, but I belive him and he is seldom wrong and never when questioned and when he does his research. Are you suggesting PET is wrong?

PS: the rings appear to be cast Iron, which would be correct.

I may have confused myself. Mahle = nikisil. And: KS = alusil.

Sorry to say you may have the wrong rings in your car. My situation agrees with Dempsey.

The results I was looking for were the ring end gaps, but thanks for the other numbers. I think your mechanic is right but I'm not an expert on the various ring types. A good second opinion would come from Jon at EBS racing.

-Andy

Not at all. These were the rings sold to me as 93010398500 which corresponds to the K/S ring set. They did appear identical to tho old ones that came out of my allusil pistons. I actually did not end up using this set as I elected to go to 98mm P/C's for a 3.2ss with twin plug. The old re-ringed P/C's are sitting on the shelf so were never run in. It is possible that I was sold the wrong rings although I verified it with the company several times that these were for K/S not Mahle before purchase. The box that the ring set came in only has the Goetze number and not the Porsche cross reference number on it so I cannot verify.

The end gaps I checked so far were .012 for the top rings and .008 for the lower scraper ring. That corresponds to .203mm and .308mm (or so) on my feeler gages.

Whew! I was afraid I was the bearer of bad news. Glad I was incorrect. But, happy to verify I have the correct ring set. When you don't do this stuff every day it is easy to get confused and mistakes can be very costly. Word for the day is "verify, verify, verify."

The end gaps for the compression rings when new are supposed to be between .004 and .008 inches. The wear limit is .030 inches. Your end gap is a little better than the ones on the last set I bought but still a little loose for new rings. Do your old rings have bigger gaps? I'm not saying I wouldn't use the rings you bought just making sure you use the best available rings (maybe the old ones).

-Andy