When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hey everyone, I need to decide on whether to get cast rings or chromemoly rings to go with the new hypereutectic pistons I'm gonna put in. Two factors I've learned are: 1 - ring gap difference from cast to hyper pistons due to ring pack placement (rings are closer to combustion chamber and therefore hotter, expand more in the hypers). 2 - The chromemoly rings are harder to get to seat than cast. Which will work better for the hyper pistons?
The hyper.. piston should fit with less clearance because they have less expansion. I would expect closer ring end gap clearance. Chromemoly is really a misnomer but those type of rings are nomally for racing aps.
Originally posted by beartracks The hyper.. piston should fit with less clearance because they have less expansion. I would expect closer ring end gap clearance. Chromemoly is really a misnomer but those type of rings are nomally for racing aps.
The piston to cylinder clearance should have nothing to do with the ring end-gap.....The cylinder size determines the ring end-gap,
not the piston size......
Originally posted by Tronick Hey everyone, I need to decide on whether to get cast rings or chromemoly rings to go with the new hypereutectic pistons I'm gonna put in. Two factors I've learned are: 1 - ring gap difference from cast to hyper pistons due to ring pack placement (rings are closer to combustion chamber and therefore hotter, expand more in the hypers). 2 - The chromemoly rings are harder to get to seat than cast. Which will work better for the hyper pistons?
1. You're right, follow the piston manufacturer's instructions on ring gap or risk losing the top of the piston.
2. Get the moly rings. The key to ring seating is the finish hone on your cylinder walls. Moly rings like a very smooth hone and will probably seat before your cam is broken in.
As far as rings goes, moly I perfer. Most people get the rings mixed up. You have cast rings then moly ring then chrome rings, These are the most popular, I know there are more. Moly rings get called Chrome Moly also, but the Chrome rings are hard rings.
Moly rings will seat very easy, as georgedavila stated they will seat befor the cam is broke in. I have heard they can even by the simple turning the engine over when installing pistons on the engine stand. I would have to say almost all Car companys use moly rings. Imports like the chrome rings.
Keith Black pistons need more ring gap. They have stated that they have the ring package high on the piston and the heat expands the ring more. I have seen heads of piston pulled right off and piston pin pulled out because of ring bind. Hyper pistons do not transfer heat as well as forged there for sending more heat out the rings.