John Deere Spoker D

Bendeere · Jul 16, 2011

I have a 1925 D with the 6 1/2 bore. The block is bored .45 over. What should the ring gap be? And also what should the piston tolerance to the cylinder wall be? Thanks can call if needed. 517 610 1282 Ben

rustred · Jul 16, 2011

ring end gap is .003-.004 for every inch of cyl. bore.looking in the nieghborhood of .020-.026 not sure of piston clearance on those big pistons, but i would think .oo7 would be ok. dont want to get them too tight under load.

jd b puller · Jul 16, 2011

Are the pistons aluminum or iron? If aluminum, are they Cast aluminum or billet? Different expansion rates. On forged or billet piston, you'd be closer to 14-16 thou clearance required. Cast, less. Iron, less.

Pistons are supposed to be built with the clearance built in to them for the bore. So you SHOULD bore it to 6.545". Check with who built your pistons to see what they say.

Bendeere · Jul 16, 2011

The pistons are cast

Bendeere · Jul 16, 2011

NOS Cast iron sorry for the confusion

jd b puller · Jul 16, 2011

(quoted from post at 13:30:58 07/16/11) NOS Cast iron sorry for the confusion

NOS cast iron shows 6-10 thou in the IT manual. Use the same for 045's

Ring clearance listed above.
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John Deere Spoker D

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rustred

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