another 372xp question...

[Northerner]

So on the OE 372s, there's 2 different cylinder/piston kits available, EPA and non EPA. Whats the dif? i see the epa has 2 rings, anything else? Seems the non-epa version has gotten a different part # and the price has gone waaay up from my supplier.

 

[Duce]

Epa has 2 ring piston, non-epa has a 1 ring piston. Both will work. 2 rings are 1.2mm thick and 1 ring is 1.5mm.

 

[Czed]

So on the OE 372s, there's 2 different cylinder/piston kits available, EPA and non EPA. Whats the dif? i see the epa has 2 rings, anything else? Seems the non-epa version has gotten a different part # and the price has gone waaay up from my supplier.

All that I've received in the past few years is 2 ring pistons
I believe the one ring might be nla.

 

[qurotro]

They both work. Meteor makes both too. Some like the 1 ring cuz less drag? Ring end location when porting.

 

[Mack 880]

Paper on two rings versus one ring:

Gas escape to crankcase: impact of system parameters on sealing behavior of a piston cylinder ring pack - International Journal of Energy and Environmental Engineering

Internal combustion engines are the generators of energy for many transportation applications, but they still have an overall low efficiency due to mechanical and thermal losses. The combustion chamber is the core element of the engine and it ought to be perfectly sealed; however, some of the...

link.springer.com

 

[Stump Shot]

All that I've received in the past few years is 2 ring pistons
I believe the one ring might be nla.

I just ordered a one ring OEM piston here not too long ago... https://www.hlsproparts.com/ProductDetails.asp?ProductCode=503691271

 

[Outback]

SON OF A, it deleted my typins. Your diesel words are biggum sir. The 2 rings feel torqier in the wood down low if you lose rpm. Up high the pressure seals 1 ring or two with about the same pressure. Its the cumbustin that holds the ring to the wall at rpm when the gas pushes the ring down it sneaks behind it and pushes out too, its not the ring tension when its runnin. I feel the extra ring drag is about the same as the couple different grams in weight of the meteor vs the oem piston. If you care too much you want the single ring oem piston. If your reasonable it really doesn't matter in the real world. People leave the second ring out all the time. Not me so much.

I raise you more painful diesel thinkin. Do chainsaws fly?

https://www.sciencedirect.com/science/article/pii/S1000936120303344

Edit: I need more coffee.... If its ported I'd care more about the ring pin locations than whether it had two rings or one or how thick the ring is. Stock I'd really want both rings. I also feel like the "heat transfer" ring stuff is a little dubious both ways. I will leave one out for reasons, but I don't like too.