K301 crank movement

[danderson]

When the piston is at top dead center I can move the crank maybe a 1/4 inch without the piston moving. I can see the rod through the cam hole and it moves. Thinking this is not normal. Would this be slop where the rod attaches to the piston pin?

 

[mfrade]

Yes, it's normal and yes it is partly the "slop".. (slop being a technical term!) LOL

 

[danderson]

I was worried something was drastically wrong. What causes it?

 

[mfrade]

At the very top of the stroke ( and bottom) the arc is really narrow. So you don't have a lot of vertical movement, mostly horizontal as the crankshaft comes around. This and any freeplay in the bearings magnify the effect.