clearance in rebore cylindef for oversize pistons/rings(gap between piston cylinder)

[raczekp1]

i had to put oversize pistons and rings in my 4.5hp Evinrude 80'.
the repair shop will rebore cylinders but the guy asked about clearance between piston and cylinder wall.
how much it should be.piston while working will expand some dimension, so how much cylinder shoud be wider.and clearence cant be to much to not loose compresion

 

[bob johnson]

Re: clearance in rebore cylindef for oversize pistons/rings(gap between piston cylind

i had to put oversize pistons and rings in my 4.5hp Evinrude 80'.
the repair shop will rebore cylinders but the guy asked about clearance between piston and cylinder wall.
how much it should be.piston while working will expand some dimension, so how much cylinder shoud be wider.and clearence cant be to much to not loose compresion

well with out knowing the exact specs to your motr, I would still think that it should be what ever "oversize" your new piston is.

so if you are installing a .020" oversize piston, then he needs to bore the hole .020" more than the ID of the good cylinder.

but I wonder why the machinist cant find that info..

bob