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I think I understand what you mean. Your thinking that when the motor heats up, the pushrods expands, and this would make the adjustment tighter correct? Well..everything expands and grows not just the pushrods, the rocker arms, the heads, the pistons, the bores, the rings..everything. The heat excites the molecules causeing them to move. Just like airing up a tire..You add molucules they bump into each other, they have now where to go, they expand the tire..It heats the tire up also....

When pressure goes up so does temp they are proportional. As pressure goes down so does temp. This is why those old Deodorant cans get real could when you use them for a few seconds. This is actually the basic principle of how a A/C unit works.



No Bob,the pushrods and valves are a denser(tighter grained)material and are less effected by heat.Combustion tempertures have the greatest effect on a pourous cast material such as the head,combustion tempertures are transferred through out the mass casting causing the growth, conversly the rockers,iron or aluminum conduct the heat from the head mass also,but to a lesser degree than the head mass.Valves are the lest effected since they(exhaust) are designed and made of material that would only be effected by extreme heat that you will not see in an engine.The main growth to be concerned with here are blocks and heads or "mass,pourous metals"



I agree with that Bob...I was actually trying to think like his friend in the first paragraph LOL, where the contradiction occured LOL.

Let me ask you this...
Looking at those old KB Hyper style pistons. They always call for a much larger top ring gap like .0065-.007 per inch of cylinder Vs standard forged pistons were .004-.0045 is usually a good target for end gap/per inch of bore.
Looking at the piston I noticed how much the the top ring is moved up toward top of the piston.

This made me think for a second. I know the material used is diff and has a diff expansion rate, and even requires diff piston wall clearance also.

Here is what I first thought. The ring being much closer to the top of the piston would be exposed to much more of the combustion temp and heat.
Also I thought about the ring placement in the bore compared to the water jacket. Id imagine that the top of the cylinder runs generally a bunch hotter than the bottom portion. Which this is the point were all the combustion process works. maybe this is why the cylinder mostly wears at the top.

Anyways
From a engineering stand point, or from a veiw of guys smarter than me. Why? Why have the top ring so high on the piston? Why not have the ring were it suppose to and have a normal ring gap?

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