John Deere H oversize block

[Otis Wolkins]

I have a 1941 John Deere H block that is rebored 0.090 oversize--I can find 0.090 rings but not the piston--can this block be resleeved back to original? I did find 0.090 pistons from Kuhns but they are domed and look like they are too long for the cylinder. Help!!

 

[NY 986]

I have a 1941 John Deere H block that is rebored 0.090 oversize--I can find 0.090 rings but not the piston--can this block be resleeved back to original? I did find 0.090 pistons from Kuhns but they are domed and look like they are too long for the cylinder. Help!!

In theory yes it can be resleeved. Just need to find the appropriate material for the sleeve and a shop to weld it into the block.

 

[Duner Wi]

Melling has repair sleeves in 3/32 or 1/8 inch wall thickness for 3 9/16 pistons. I don't know about the welding part, most repair sleeves are press fit. I sold my H years ago and am not up on the latest piston and cyl repairs

 

[buickanddeere]

Pullers have sleeved the H block out to take plain ordinary low cost stock pistons from a 40 or even a 420 iirc .

 

[Otis Wolkins]

Thanks for the replies---does anyone know where I could get 0.090 oversize pistons for my block as this seems to me to be my best way forward.

 

[NY 986]

Thanks for the replies---does anyone know where I could get 0.090 oversize pistons for my block as this seems to me to be my best way forward.

Try A & L Parts. Penn Yan, NY. 315-536-0543 M-F. They part out JD 2 cylinders and he has a barnful of new and used.

 

[Duner Wi]

This is old Sealed Power catalog. Be sure length is adequate.

 

[Duner Wi]

Melling website and look at PDF>

https://melling.com/wp-content/uploads/2025/05/2026-Cylinder-Sleeve-catalog_condensed-version-01212026_TOC.pdf

View attachment 157211

 

[Otis Wolkins]

Thanks for the replies. I thought I would see if the domed piston, when installed in the cylinder, would give clearance to the head and it did---approximately 1/4 inch assuming a reasonable value for the compressed head gasket. Is this sufficient clearance?

 

[JIM MN]

When valves are open, will they hit the face of the piston?

 

[buickanddeere]

When valves are open, will they hit the face of the piston?

It depends , assemble and measure clearance as the engine is rotated .

 

[Otis Wolkins]

It doesn't look to me that the valves will hit the top anywhere given the valve timing--I will go slow when the head is attached to make sure they don't hit. Thanks for the caution.

 

[buickanddeere]

It doesn't look to me that the valves will hit the top anywhere given the valve timing--I will go slow when the head is attached to make sure they don't hit. Thanks for the caution.

Would have been the tike to re-grind the cam and followers when apart . They do wear after 75 years

 

[Otis Wolkins]

I thought about that but the owner said it ran great when he bought it. I will see if my gamble pays off!

 

[Duner Wi]

To the best of my knowledge a John Deere H cam timing does not have valve overlap. There for under normal conditions valves will be closed when pistons are at TDC. Is there something I am not understanding?

 

[Otis Wolkins]

My "valve timing" comment was not clear---what I meant is what you more clearly stated. I don't see how the valves could hit the piston, but I will try to be more clear in the future.

 

[Straanger]

Stick some modeling clay to the top of the pistons and turn the engine over by hand, then take the heads back off and you can check the thickness to see how much valve clearance you have.

 

[Otis Wolkins]

Great idea---I'll give it a try.