656 block letters

Mikeinpa · May 5, 2019

I am doing a inframe rebuild on my 656 gas (263). Ive pulled the head and pistons. Ive noticed stamped into the block face next to each cylinder there is a letter. From front to back its C E C D D E. Not sure what this is? Ive heard possibly the bore size? Didnt know engines could have different bore sizes cylinder to cylinder? Anybody know what these letters mean?

pete 23 · May 5, 2019

Those letters are bore sizes that were used at the factory because no two bores and no two sleeves are exactly the same. Darn close but not exact. So, they had their sleeves marked and bores marked for best fit.

There are no sleeve and pistons sets available that are marked though so the marks are ignored. Always try all sleeves in all bores to select the best average fit so you don't put the largest sleeve in the smallest for for instance.

On the diesel D282 IH always made a .002, .005 and .010 over size sleeve to help over come poor fitting sleeve problems. I put in a lot of .002 in them to get a tighter fitting sleeve. Requires honeing with rigid hone and trial and error. Gasoline engines never had that option as they were not a prominent problem.

656 block letters

Mikeinpa

New User

pete 23

Well-known Member

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