I am rebuilding a previously seized engine and after sanding the sidewalls of the cylinder and piston with 1500 grit sandpaper (there was absolutely no other choice) The piston requires much force to move in the cylinder (I put the crankshaft on the piston and it did not move) I don't know if that is normal but I suspect it is not.

Is this normal and if not, how can I fix it?

Note 1: It is my first time rebuilding an en engine Note 2: It is impossible to get any spare parts.

Edit: I partially reassembled the engine and it is quite easy to spin it by spinning the flywheel.

  • The piston should not be touching the wall, only the rings make contact. When ststionary anyway. If the piston is a tight fit then is it the correct one?
    – Solar Mike
    Commented Aug 3, 2021 at 11:56
  • What did you do AFTER sanding? How did you clean the grit out of the cylinder and off the outside of the piston? Did you measure the piston ring end gap and compare it with the spec? Did you measure the piston to cylinder clearance and compare it to spec? Are you sure the cylinder is not warped and now out of round?
    – jwh20
    Commented Aug 3, 2021 at 12:12
  • @jwh20 I poured some water and wiped it immediately then I used some dry cloth and after that I poured some oil and cleaned the excess with some more cloth. There is no spec to compare to for any of these things you asked. As I said, I have no experience with engine rebuilding and the only thing I did was visually inspect it. It seemed to be ok
    – Hristos
    Commented Aug 3, 2021 at 12:22
  • It would help if you gave more details about what type/model of engine it is and what you know of its history. Has it been sitting around for a long time?
    – GdD
    Commented Aug 3, 2021 at 12:25
  • @Solar Mike the piston doesn't seem to touch the cylinder walls. The last sentence in your comment confused me a bit.If you are asking whether or not the piston is the correct one, it is the original one with sanded sidewalls. If you are saying that what is happening should be happening, are you sure it should be that tight?
    – Hristos
    Commented Aug 3, 2021 at 12:28

1 Answer 1


A friend (who is a car mechanic) came by and told me that everything is as it should be. I verified that with another friend so i am quite confident that it is ok. I will update once i start the engine.

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