(I originally posted this in the prelude section, but perhaps it belongs here instead)

I've been running an '89 h22 swap for about 3 years now and it's time for some new piston rings. I'm having trouble finding some good info on the difference between standard and low pressure rings.
I've read about tangential pressure and cylinder wall pressure and how standard tension rings exert pressure around 180-240 psi, while low tension rings are around 90-160 psi. It's clear to me which deliver the least amount of friction and that sounds good to me and my cylinder walls. However, I'm running a 11.0:1 cr and I'm really not sure if the low tension rings would do the trick. I'm assuming a compression test would yield numbers higher than 160 psi (even though I haven't done one yet and I'm not going to till new rings are in place. I don't even want to know how bad it is right now).

Is the math that simple? If an 11.0:1 cr yields over 160 psi on compression testing, would a low tension ring rated at 160 psi max be insufficient? That would make sense to me, but I'm not pretending to know something I've never dealt with before.

After further reading it seems the ring I need will be more decided on whether or not I have shallow or deep groove pistons, and I don't know the answer to that one either. Anyone care to enlighten me?

 

I am not going to say its a sales gimmick, BUT do you know why there is a ridge at the top of a worn out cylinder and how a portion of rings actually work. Some of the compression during ignition gets in behind the ring and forces the ring outward to make it seal better, that is one reason rings went from square like corners to rounded corners, thats not the only reason though, to ease the travel of some of that compression behind the ring to help it seal to the wall better.

Some drag racing technology actually drills holes in the top of the piston down to the first ring land to allow the fuel air mixture to seep through these tiny drilled passages so that the fuel will burn behind the rings exerting massive amounts of pressure to force the rings to seat to the cylinder walls, these engines get rebuilt all the time and this procedure will not work on a daily driver, it requires heavy maintenance.

I only know not to put moly rings in a used cylinder, moly goes in a fresh cut cylinder, beyond that, and what I mentioned, lets get some more input for you.

 

Thanks for the reply Duane.

That is interesting. So if ignition pressures are seeping between the ring and piston, forcing them against the cylinder wall, is it safe to say that standard vs low tension rings only makes a real difference on upstroke? (I guess thats not really imperative to finding the answers to my questions, but I like to learn whenever I have the chance).

I'm looking at Mahle rings, and top ring materials are listed as ductile iron, plasma-moly. So those would be a no no? (I understand that resleeving is the only real option I have with my h22 if I want fresh cylinder walls).

Basically, if someone told me that I could just walk into the honda dealership and ask for 2001 prelude piston rings and they'd work like a charm, I'd do it (oh, btw. euro r h22 is what I'm dealing with here). I will be pulling this engine apart for a complete rebuild eventually, but not until I leave this stinking state of MI and find a job in FL, so whatever will get me by for now is what will make me happy.

 

bump.

Anybody else have some info on this?

 

The tension number only refers to the oil ring tension.Low tension rings are typically thinner (radially).If the pistons are cut for low tension than you can't use high tension.But you can use low tension in a piston cut for high tension.Talk to Mahle to find out which ring you can use with your pistons.Cylinder compression numbers do not relate to ring tension psi.I typically use low tension rings myself when available.And moly rings will be fine on new or old bores.I would use mahle rings.

 

Sounds good, I'll talk to Mahle about it. Thanks alot for the replies guys