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I don't know for sure if they are the same, but I seriously doubt that they would be the same. It just doesn't seem like they would be to me, being as they took the effort to do everything right for the turbo internals. Not 100% though, I might be wasting your time :)
 

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Don't be mislead...

There is no such thing as a chromoly piston ring. There are chrome sets and there are moly sets, but chromoly is a myth.

There's a back issue of Popular Hot Rodding Magazine that discusses the benefits/advantages of both/either, I'll try to dig it up if anyone's intersted.

The choice between the two is dependent on the power you're generating and I think there is a fuel type variable that gets thrown in too. The chrome rings are good, and less expensive but have their limitaions with regard to seal maintenance under high compression. The molies are kinda expensive but maintain a superior seal even under really high compression. I think there was an issue related to the chrome's ability to hold up, long term, with the use of nitromethane and nitrous oxide.

If you're not generating an enourmous amount of power, say 450+, and aren't using exotic fuels, I'm pretty sure the chrome rings will serve you well. However, this is not an area where I claim any expertise so do your reasearch before you choose.
 

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I Did A Little Research, If'n Anyone Cares...

Most piston rings are cast iron (this may be pretty common knowledge)... What may not be common knowledge is the fact that there are differing versions of cast rings including alloy iron, ductile iron and some other stuff can't remember. Anyway, these are common and pretty inexpensive.

Then there are chrome plated cast iron rings or "chrome" rings. These are said to perform a little better than the cast iron as they reduce chamber wall scoring. However, they evidently aren't especially long lived. Now what constitutes a long life I don't know, so they may actually be fine for your application, but I can't make any recommendation.

Now, what I wasn't aware of is that most passenger car rings are moly rings. So these are not rare or especially expensive. What makes them different/better is that the grooved oil ring is filled with moly (the groove that is). Moly will absorb oil and will reduce chamber wall friction and scoring while establishing good hydrostatic seal.

Therefore, it appears that the moly ring set would be the best bet and it may just be an OEM replacement set.

BTW: In my earlier reply I was mistaken... I found no mention, in any of the articles I read, of an incompatability of any of these rings and any fuels or any seal deficiencies. It seems that the differences have mostly to do with friction, chamber wall scoring and ring life.
 

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Discussion Starter #6
good stuff!!! I found a few sets on Carparts.com. I dont get it! One set is chrome, the other set is Moly, but if I look up a 1986 626 GT Turbo ringset, they have a whole re ring kit with Chrome Moly rings!! ANd the rings for both the 2.0 turbo and 2.2 turbo are the same. Same bore etc etc. Even some of the other ringsets are cross referenced!

peace
 

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You Know What?...

I'm taking all of my information from articles related to the maintenance and buildup of American V8s. I wonder if the "no chrome-moly" thing is a symptom of being built/designed in the US?

It would make sense that you could have a chromed ring set with a grooved oil ring and have moly filling the oil groove.

Ya know who'd be good to call on this matter?... The manufacterer of the rings. I'll see if I can dig up any more info.
 
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