What rings do i need for alusil?>???

[80sc man]

I have heard from a couple different people that the nikisil pistons take a different ring than the pistons that go along with the alusil set-up. Does anyone know what i really need here???

[kstylianos]

Most folks on this board will tell you that Alusil's cant and shouldnt be reringed as this is what Porsche specified.

A few have had success (Superman for one) and I hope to be added to this list soon. A new set of Mahle's are mucho $$.

Goetze rings for Alusil are the ones you want to use. Some sites specify different rings for both Mahle (Nickasil) and K-S (Alusil). Are they same rings, I don't know.

Steve Weiner gave me the following instructions for breaking in new rings in used Alusil's:

After your initial engine break in you'll need to do this for the next 2000 miles. Wide open throttle from 2K to about 5K RPM in 3rd gear, then coast back down to your desired speed. WOT will force the rings out into the side of the cylinder walls and help them break in. Coasting back down to speed, espically down hill, will help the rings break into the rings lands. Do this once every 6-10 miles. In between these WOT jaunts, vary your RPM's continuously and do not stay at fixed RPM for any extended time. The things to remember here is to vary your RPM's so the rings can break in throughout the RPM spectrum and WOT, espically at low RPM, will force the rings into the cylinder walls.

Steve mentioned he had a customer not follow these procedures and his rings never broke in and continued to smoke. They had to tare down for ring replacement (and I think he went w/ Mahle P/C's this time around).

[diy83sc]

I've had my K-S re-ringed on the 83. Oil consumption was high the first 1000 miles, but is now down to about a quart every 2000! I've changed the oil three times since, after the 1000, then every 3k since. I'll ask my mechanic what we used. I had this done at 104K and am now at 112K with an occasional puff of smoke on start (maybe 1 out-of ten?) I don't think this is due to re-ringing.

[jmohn]

Once again I suggest anyone who wants (needs) to re-ring Alusil cylinders should post their questions on the 944 list also, several people there have re-rung their 944 or 951 with good results and 944's are all Alusil.

Jerry M
'78 SC

[kstylianos]

Jerry, good tips.......

[speeder]

You need to get the correct OEM, (Goetze), rings for KS pistons. There are different rings w/ different part #s for Mahle, (nikasil), and KS, (alusil). I would strongly reccomend against aftermarket rings, the factory rings are the best and have the correct wall pressure for your cylinders. This has been the consensus among the Porsche engine builders that I respect.

Having said that, if your P/Cs are within spec for wear/roundness, there is no reason that rings should not seal if broken in properly. I have my motor apart at the moment, ('82 SC w/ alusil), P/Cs are close to new spec w/ 118k miles, I am reringing it. The break in advice above is basically sound, but I am a follower of the advice on the "Motoman" web site, which is that rings must be broken in properly in the first 50 miles or you can forget about ever getting full performance from your engine. Check out www.mototuneusa.com "break in secrets". Good luck!

[80sc man]

Hey thanks a lot for your help.. That break in procedure is one that all my friends and I always use when we break in an engine. It has always worked great.. Do you know where i can get the rings your talking about? I have asked people at pelican and they don't seem to know any difference between the KS rings and mahale rings. Thanks

[kstylianos]

There is a definite diffecence between Mahle and K-S rings. See the following post:

Mahle 3.0L Goetze piston rings F/S

For Mahle or K-S rings, see here:

http://www.pelicanparts.com/catalog/shopcart/911M/por_911M_enginB_main.htm

Mahle : Piston Ring Set (95mm-1.5 X 1.75 X 4.0mm)
K-S: Piston Ring Set (95mm-1.5 X 1.75 X 3.5mm)