John Deere 60 Pistons

[t martin]

Hi, I need some .045 over pistons for my JD 60. I found a set of A4787 pistons which are listed as a hi altitude piston. How do these compare to the A3435R gasoline pistons? Would they be higher or lower compression ratio?? What is the difference? Thanks.

 

[HFP]

Digging online I have found a few data points for a 60, can't confirm 100% though.

All Fuel: 4.7:1
Gasoline: 6:1
LP: 7.3:1

The high-altitude piston would be somewhere between the gas and LP, likely closer to gas. I saw numbers of 6.25, 6.34, and 6.5 various places online. Not sure I would call any of them 100% credible, but looks to be in that range.

 

[buickanddeere]

Hi, I need some .045 over pistons for my JD 60. I found a set of A4787 pistons which are listed as a hi altitude piston. How do these compare to the A3435R gasoline pistons? Would they be higher or lower compression ratio?? What is the difference? Thanks.

Lucky you to find such a set of rare pistons . Has the cam and followers been checked ?

 

[t martin]

Lucky you to find such a set of rare pistons . Has the cam and followers been checked ?

Just getting started on this project. The rest of the engine is in pretty good shape but the original block was cracked and patched poorly. I found a standard block but it has some wear so I was unable to use the pistons I took out and have to go up a size. I was shocked how hard it is to find any pistons for a 60 right now. Ring supplier quit making rings apparently so everybody is sold out right now and now the price is going up as well.

 

[ET]

If you found a set of high altitude pistons .045 oversize don't hesitate, buy them.

 

[Mark-Ia]

www.h&jmachining.com show rings for the late Model A. Same bore size. Available in standard, .045 and .090.

 

[t martin]

Digging online I have found a few data points for a 60, can't confirm 100% though.

All Fuel: 4.7:1
Gasoline: 6:1
LP: 7.3:1

The high-altitude piston would be somewhere between the gas and LP, likely closer to gas. I saw numbers of 6.25, 6.34, and 6.5 various places online. Not sure I would call any of them 100% credible, but looks to be in that range.

The seller sent me some dimensions and they sound like they will be about an 1/8th" taller than stock piston. I do not foresee any issue with this. In fact I am pretty excited to see how it runs with them in.

 

[HFP]

An 1/8th inch won't increase it much, probably in that range I mentioned. You shouldn't have much issue with pump gas until you get up into the 8:1 range. I have a 36A with all fuel pistons. I wanted 8:1. It took a Heisler head and lengthening the rods by 5/8" to get there. You are a long way from that.

 

[t martin]

An 1/8th inch won't increase it much, probably in that range I mentioned. You shouldn't have much issue with pump gas until you get up into the 8:1 range. I have a 36A with all fuel pistons. I wanted 8:1. It took a Heisler head and lengthening the rods by 5/8" to get there. You are a long way from that.

Thats what I am thinking. These are such low compression anyway that I am not too concerned about compression boost. It is not a pulling tractor, but I want it to run well.

 

[buickanddeere]

The seller sent me some dimensions and they sound like they will be about an 1/8th" taller than stock piston. I do not foresee any issue with this. In fact I am pretty excited to see how it runs with them in.

Could entertain the thought of milling the 60's head down for compression? This would be an opportunity to take a few of thou off the head's intake/exhaust port mating surface . They are usually eroded from failed gaskets and corrosion.