John deere G gasoline coversion piston selection

GHeritage

New User
I'm currently rebuilding my grandfathers styled G sn/44321. It was still in all fuel configuration and am considering gasoline conversion as there is a hole in intake/exhaust manifold. Will likely need bored .090 over as its allready at .045 and #2 has pitting. I'm concerned about piston selection as I dont want to increase compression so far as to worry about it. All this tractor does is mow some pasture or toy around. A stock G all fuel as I understand is 4.2-1 but I cant find data on john Deere gasoline conversion kits (F1075R or F1076R) to judge a safe comprression ratio. Also if anyone knows the best place to order such piston would be awesome. Thanks for the help.
 
I think the only pistons being made anymore
for 2 cylinder Deeres are the M&W style gas
pistons. They are about 6.5-1 compression
ratio. I put them in my 1950 G back about
15 years ago. Itll run fine on regular 87
octane gas and should be about 55hp then if
you put a gas manifold on too.

Back then it seemed like lots of places
carried those pistons, but I've been
reading about some aftermarket pistons
becoming scarce now. They were $450 a set
back then. Dont know what they'd cost now.
 
Was a fellow Hinrich tractor or repair ? Who advertised in trade magazines and maybe still does ? He was most helpful when I rebuilt a G for a guy.
 
I dont know if a guy could do this, but if you have to machine it out to 90 and still find pistons, could a person sleeve it and put in 70 gas pistons? How bad is the pitting? Or could a person find some oversize 70 gas pistons?

Just throwing that out there because at some point i will be working on a couple G's and just seeing how close those ideas might be.
 
IIRC 70 gas is different bore size than a G. The 70 all-fuel is the correct size and likely scarce as hens teeth ? but too low of compression.
 

Extreme Tractor parts has a CNC mill. They custom make pistons by the hundreds to any diameter, ring width, pin height , compression ratio .
7:00 to 1 is safe on pump gas. May as well have the wear ground out of the cam and the lifters trued up.
 
Mike M,

you are correct, i didnt include that, but yes, the bore is smaller, stroke is the same, but the compression in a 70 is higher, so my thought was if you cant find oversized higher compression G pistons, would sleeving it and going with a 70 gas, oversize or standard be an option?
 
You can make a phone call to Hinrichs Repair in Lyndon,IL Jerry can help you set your tractor up right. He sells the correct pistons and has 40 plus yrs. experience. He runs a add in Green Mag. PH. # 815-778-1900, 815-499-6580.
 
Thanks all. I'll give Hinrichs a call. I've come across the extreme tractor parts before but wasn't sure if I needed more data before calling in to order pistons. The F736R pistons I have are still in great shape. Plus I picked up a pair of what I assume is MandW style .045 when I bought the upper water pipe manifold from my father's old neighboring farm. I just think I'd rather not have to sleeve it yet. The pitting on #2 isn't to bad from water getting in through exhaust manifold when it set out. but while it is apart I want to make it right. I finally found someone close to rebabbit #2 con rod that seems capable. The tractor is getting gone through after my brother borrowed it to mow and left water in it when putting it up. Busted head and water manifold. Got lucky on the block. It ran very well the way it was but a little extra safe HP wont bother me.
 
Well folks hinrichs dosnt carry G parts anymore. Sharps antique tractors dosnt have any in stock and cant say when they will as they are changing manufactures. Yesterdays tractors dosnt have any in stock from their supplier. Steiner's was a simple no. So extreme tractor parts can make them, pistons rings and pins for $1100. A lot of money compared to the $500 from the others that are out of stock. But they wont give up their supplying manufactures understandably.
 
Well folks hinrichs dosnt carry G parts anymore. Sharps antique tractors dosnt have any in stock and cant say when they will as they are changing manufactures. Yesterdays tractors dosnt have any in stock from their supplier. Steiner's was a simple no. So extreme tractor parts can make them, pistons rings and pins for $1100. A lot of money compared to the $500 from the others that are out of stock. But they wont give up their supplying manufactures understandably.
 
Well folks hinrichs dosnt carry G parts anymore. Sharps antique tractors dosnt have any in stock and cant say when they will as they are changing manufactures. Yesterdays tractors dosnt have any in stock from their supplier. Steiner's was a simple no. So extreme tractor parts can make them, pistons rings and pins for $1100. A lot of money compared to the $500 from the others that are out of stock. But they wont give up their supplying manufactures understandably.
 
Man that stinks! I had been seeing people
post on the "2 cylinder club of Facebook"
page saying they were having trouble
finding pistons. I wasnt sure what models
were in short supply. Guess it's all of
them.

The only bright side of having them made is
you can make them exactly what you want.
Ray will know how much compression you can
get away with on cheap gas.
 
We have new 6 1/2 inch G pistons on the shelve. They are tall enough they can be machined to what ever compression you want. Only catch is your block has to be able to go to 6 1/2.
Not all of them will.
 

I wont be able to machine that far and feel comfortable. There is only .28 thickness i measure on the bottom of the bore wall. I dont think taking .375 out of .56 screams dependability. I can get pistons made from extreme tractor parts for $1100 rings and pins included. Sharps and a few others are all out of stock and not sure when they will get more. Sharps at least was sure they would get more eventually and are priced just shy of $500. Not sure I like the idea of waiting untill who knows when for them. I did speak with a local machinist who may take on the project of making me some going off my set of .045 over M&W style. Be he still isn't sure on what aluminum to use yet or how much elliptical shape to machine into them for heat expansion.
 

JLG is ray the fellow I spoke with at extreme tractor parts or someone else? I'm not the greatest with names and have spoke with many new people today.
 
(quoted from post at 19:23:06 02/12/19)
I wont be able to machine that far and feel comfortable. There is only .28 thickness i measure on the bottom of the bore wall. I dont think taking .375 out of .56 screams dependability. I can get pistons made from extreme tractor parts for $1100 rings and pins included. Sharps and a few others are all out of stock and not sure when they will get more. Sharps at least was sure they would get more eventually and are priced just shy of $500. Not sure I like the idea of waiting untill who knows when for them. I did speak with a local machinist who may take on the project of making me some going off my set of .045 over M&W style. Be he still isn't sure on what aluminum to use yet or how much elliptical shape to machine into them for heat expansion.

Just spec your own pistons then to CP or Diamond etc. CP will mirror cut the bottoms and you can end up with some ultra lite pistons, nitrile pins, spec your own ring sets, whatever you want. Just a question of money and I assume that if you do it correctly, you will never have to redo it within your lifetime and you may even be able to sell some additional sets as there seems to be a market void.
 
thastinger,

i just looked at the websites. impressive. I dont know that i could swing a checkbook big enough to cover the cost of a pair of 2 cylinder pistons hahaha
 
(quoted from post at 12:56:38 02/13/19) thastinger,

i just looked at the websites. impressive. I dont know that i could swing a checkbook big enough to cover the cost of a pair of 2 cylinder pistons hahaha

Oh yeah, not cheap at all. I've paid CP 1500 for 2 pistons before and 1200 for 4 more than a few times. Have never had a failure with their pistons though on engines making 150HP a hole and spinning 9K with piston speeds approaching 5500FPS.
 
for John Deere 2 cylinder performance questions call Blackburn Performance in Durand Michigan they are top notch in G performance pulling tractors and 2 clinders in general they probable have what you want or know where to locate it. I dont have there number but it should be on there website.
 

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