Piston has rotary play in cylinder

SkyenX

New Member
Joined
Sep 3, 2019
Messages
26
Hi guys,
I was cleaning the carbon off my piston and while scraping, noticed that the piston can rotate ±5 degrees in the cylinder. Shouldn't it be completely constrained, except for up and down?
Is my wrist pin wearing out? Thanks for any help
 


GreasyChris

Well-Known Member
Joined
Jan 3, 2019
Messages
788
It sounds like it could be the wrist pin and or bearing. Maybe even the crank bearing. Could be related to your play in the bottom you described in your other post
 

Karl Snarl

Active Member
Joined
Sep 20, 2019
Messages
138
oh man, no no no. if it is twisting, you need a new gudgeon pin and bearing. its ok if it has a slightly side to side perpendicular to the rod, but twisting is a sign tht wrist pin ( gudgeon) bearing is bad or not the right one. i use a wrist pin bearing made for stihl chain saws. it's slightly wider and thicker than the stock bearing. i get it from a small engine and power tool shop a few miles from my house. they cost me like 5 bucks each. well worth the money when you compare to a new jug, pin, piston and rings.
 
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