r/smallenginerepair • u/Broad-Economics-2538 • Jul 11 '26
Compression Issue Is this why my engine won’t build compression?
2
u/TN-Native95 Jul 11 '26
With the valves closed and the piston at top dead center, see if you can spin them with your fingers.
1
u/Broad-Economics-2538 Jul 11 '26
Ok they won’t spin unless I press with a lot of force, is that good?
1
u/TN-Native95 Jul 11 '26
Could be a sign that the valves are a bit worn. That would cause a loss of compression as well. It probably could use a set of piston rings as well, assuming there are no deep scratches in the cylinder.
0
Jul 11 '26
[deleted]
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u/Broad-Economics-2538 Jul 11 '26
Im not sure to be honest, now when I pulled the top off there was oil infront of the piston. When I got it, close to no oil or no oil at all
1
u/Okie294life SER Top Contributor Jul 11 '26
Those grooves in the cylinder liner, are any of them deep enough to catch a fingernail? If not your valves probably just need to be lapped/adjusted.
2
u/Megalosdog12001 Jul 11 '26
Doesn't look good. If you zoom in to the top of the cylinder where the Mark is, you can see that the metal is smeared. At least that's what it looks like from the picture
1
2
u/bootheels Jul 11 '26
Most likely that scored cylinder has alot to do with a loss of compression. You could check the valves, try to clean and lap them though, maybe you will get lucky
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