Ring thickness

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Imagemineye

Well-known member
Not sure if this post belongs in here, so feel free to move it.

I am wondering about thick vs thin rings. It seems thin rings are prone to wear the bore less (less friction due to smaller contact are with the bore) but isnt it the rings job to conduct heat from the piston to the cylinder wall and wouldn't that help prevent detonation?
I am building an engine that will see boost, but that doesn't really matter with this question, does it? I am just uneasy with the idea of detonation and grenading something I will have put so much effort into.
One of the things almost always mentioned when referring someone to autotec for custom pistons is the ability to have them made for thin rings, is it just always better to have a thinner ring?

I am super appreciative for all of you who contribute to this forum and answer questions like these. I have learned quite a lot about the internal combustion thingy together through this forum, let alone Ford Straight Six.
Thanks,
Gem
 
I think the preponderance of heat in the piston is removed at the aluminum skirt, which sees cooling oil splashed on the underside of the piston. Oil temperature usually is within ten degrees of coolant temp, so that is significantly below the combustion temps the top of the piston sees. I've seen boosted engine get pressure oil squirters on the underside to aid cooling and reduce detonation, but I haven't seen boosted engines revert to thicker rings for better cooling.
The biggest knock I have on thin rings is if the engine is not maintained with periodic oil changes the oil rings are more likely to gum up with varnish and lose control leading to premature excessive oil consumption. This is because they generally have lower tension.
 
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When seeking to get custom pistons for forced induction, the top ring should be moved away from the top of the piston as much as possible. So I agree with FTF answer to your question regarding heat . The rings are sensitive and can fail from heat, so I don't think their job is related to heat removal, but the pistons job and/or oil spray. As to the ring size, it can often be a tradeoff, too thin and they may not have a long life, too thick and they create more drag and they may or may not provide more life depending on how much boost or how hard you drive it.
 
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