Cylinder bore

[Flagman101]

I am rebuilding my old 1973 atomic four.
I have purchased the overhaul manual from MMI.
In the book the piston bore shoudl be 2.562 2.563
I measured all of them and they are 2.554-2.556. Thats a lot smaller.
Are the measures in the book maximums?
Thanks

[Don Moyer]

You sort of have me over a barrel on this one. To answer your specific question first, the dimensions in the manual are not a maximum value, but the upper and lower limits of the factory new specification.

Assuming the correctness of your measurements, your bores are .006" to .008" smaller than standard, which is considerably less than the skirt clearance of any original or aftermarket piston we know of. Would you please measure the diameter of the bottom of your pistons perpendicular to the wrist pin? This is the area on the piston where skirt clearance is established.

Don

[Flagman101]

I will remeasure again. I will also have a professional machine shop do it anyways.
My rings were shot, as i had mor than .025 of end gap.
So i probably did something wrong when i measured.
Cold medicine can do that.