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Discussion Starter #1
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?
 

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Uh, oh.. Yeah, tire pressure increases as it gets hotter. Isn't water the only thing that expands as it gets colder?
 

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Discussion Starter #4
Daaaaaaaa what was I thinking???????? :(

So then why isn't the compression lower when it's cold?
 

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I would say its because the oil film is thicker that coats everything in the cylinders. Once it warms up, it gets thinner=lower compression.
 

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Wel if that one messes you up I checked mine hot and cold got the same reading on both, new gauge 125 psi, man thats alot of pulling for no apparent reason lol :D
 

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Hey Form-what did your mother tell you about pullin on things for no apparent reason? :doh:
 

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Why do you think I wear glasses,,, so when I look back I can see the cat lol
 

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:blahblah:
 

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You are getting good psi readings. you should be less compresion when the engine is hot due to the fact that the air is not as thick when it is cold.
 

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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.


RIDE SAFE
 
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