Is it a 268 or a 256 CID engine

[65intheBurg]

I am currently rebuilding my 5610 (LA314C, 256CID engine with a 4.4 piston and a 4.2 stroke) with a new crank and pistons while reusing the existing connecting
rods. When I installed the crank and pistons, the pistons now run above the engine block by .120 +/- . So I compared the new crank to the old crank and they
measure the same, 4.4 inch stroke (the old crank even has 4.4 stamped on it). But wait, I thought this tractor code says I have a 256 engine with a 4.2: stroke.

I am thinking the engine or the crank have been previously replaced with either a 268 engine or a 4.4 stroke crank and short pistons. I would like to verify
the CID of this engine to see if it is a 256 or a 268. Any thoughts? Thx

 

[Destroked 450]

Both engines share the same 4.4 bore and thus would share the same block
The engines serial number may tell what tractor it was originally built for

Regardless of what it was your new crank is 4.4 stroke instead of 4.2 so the 256 pistons you received won t work
Personally I d send those pistons back and get a set of 268 pistons, the extra torque of the longer stroke is noticeable

 

[65intheBurg]

Thanks, I will try to do that. So then I assume the 268 pistons are shorter from the wrist pin to the crown? I will have to find out the dimension differences
between the two pistons. I assume the block dimensions are the same for either engine.

 

[Destroked 450]

Rod length is the same on all of the engines so to compensate for stroke length they move the pin hole on the piston
A 268 piston should stick out of the block .011 - .023