What should normal compression be on a cold motor?
Thanks
ya don't take readings on a cold engine......
ya need the metal to temp so you get a good seal and proper tolerances.....
warm it up for 5-10 min and then pull the plugs
no big deal
I will back Ken up on that, compression readings should be taken with the engine warm and the valves set correctly.
Section 3-1 of the manual states overhaul the engine when......
Compression pressure in one of the cylinders is less than 800kPa (8kg/cm2, 114psi)
Difference in compression pressure between the two cylinders is more than 200 kPa (2kg/cm2, 28psi)
Both compression pressures are below 1000kPa (10kg/cm2, 142psi) even if they each measure more than 800kPa (8kg/cm2, 114psi)
So the answer is........if 1 cylinder is below 114psi, or if the difference between cylinders is more than 28psi, or if they are both below 142psi the engine need attention.
Also be sure to open the throttle when checking. I had a 50psi difference between a closed throttle and open throttle.
hot 165-180 range
but cold, i've seen 100-140....and that will scare you to think your engine is fried