Mahle Piston Rings

[Joesixpack]

Yeah because of the low expansion of the steel you can run them tighter.

 

[Smokem]

Straight from Mahle;

0.023-0.025" top ring
0.018-0.020" second ring
0.015-0.020" oil ring

But as mentioned earlier, clearances are not a one size fits all.

 

[Pudge]

Did the rings originally mentioned happen to be Mahle heavy duty chromoly tool steel rings, or whatever their primo line is called?

 

[Drothgeb]

Not sure, it's just the rings that come with the piston kit.

 

[Todd W]

second ring must be looser than first ring not to build pressure between them.

Straight from Mahle;

0.023-0.025" top ring
0.018-0.020" second ring
0.015-0.020" oil ring

So what is the thinking here. Tighter second ring on stockish stuff and looser second ring on high performance?

My hellfires from Ackerly and Childs came with instructions to have the second ring looser than top.

 

[Drothgeb]

So what is the thinking here. Tighter second ring on stockish stuff and looser second ring on high performance?

My hellfires from Ackerly and Childs came with instructions to have the second ring looser than top.

From all of my research, that seems to be the case. Mostly due to high boost.

Looks like I'll end up buying a set of +.040" rings then filling them to fit.

The preferred range for a 800-1000hp build seems to be .025-.030", .030-.035", .015-.020". On the low side for steel rings, on the high side for iron.

 

[Runninlean]

So fixing to start putting my late model CR together and was looking at going with the following.

Piston @ .006 after piston coating Mahle alloys
T @ .025
M @ .030
B @ .015

will likely see around 80 psi of boost possibly some mild nitrous adding in the mix down the road. Mostly ran on the track with some weekend street time.

Just wanting to get peoples input on if they see any cons.