We have been talking about taking compression hot and cold on other threads so I tried both.
I have like 147 cold and 125 hot! Quite a difference! Of course cold expands and hot contracts but should there be this much diff?
When the engine is cold, you have a tighter fit of the piston into the cylinder. That is what causes cold seizures in engines. As the cylinder sleeve heats up it expands, reducing the friction between piston and cylinder, that is the reason for the different alloys being used, piston= aluminum, rings=chrome molly, and cylinder coated steel.
If you doubt this, try starting a sled a -50 f.
A forum community dedicated to snowmobile owners and enthusiasts. Come join the discussion about performance, troubleshooting, trails, maintenance, riding tips, modifications, classifieds, accessories, and more!