JD730

A friend of the family has a 4BT cummins he's rebuilding right now and is looking for the rebore specs. Cylinder walls are scored bad, bore or bore and sleeve are the only options.

He's current plan is to rebore .5mm over and go with a set of oversized pistons. What he needs to know is the min/max dimension of the bore at .5mm oversize.

Thanks

patdaly

From my Cummins recon manual:

Stock specs given as they don't have numbers for .5 and 1 MM overbore, just add .5mm ( .0196 ) to the dimns.

Cylinder bore:
Min: 102.000 MM ( 4.0161")
Max: 102.116 MM ( 4.0203" )

Out of round : .038 MM ( .0015" )
Taper: .076 MM ( .003" )

Piston skirt

Min: 101.823 MM ( 4.0088" )
Max: 101.887 MM ( 4.0113" )

HTH.

JD730

I keep telling him that, I think I'm going to tell him to find a different machine shop too.

Thanks for the numbers, but I also have the shop manual and the technical/troubleshooting repair manual and I have the same numbers.