G JD

Anonymous-0 · Jul 4, 2011

Looking for tips on getting more power out of my 1952 John Deere G. It currently has an all fuel manifold and was overhauled 4 years ago and bored to .045 oversize. We had it on the dyno and it turned out 38 hp and 417 ft lb of torque. Would a Johnson gas manifold help out any? Would like to know before i shell out $250 plus for it. Thanks in advance!

PopinJohn · Jul 4, 2011

The manifold will help somewhat. I paid $125 for mine.
However, if you still have all-fuel pistons with the low compression, the gain may not be very much.
The upgrade to high compression aluminum pistons and a gas manifold, (doesn't have to be a johnson) will usually get you about 50 hp.
Another approach instead of the pistons is to locate a "flat head" and swap it out for the one you have.
You've got to get the compression up to get more power.

Deere Scotty · Jul 4, 2011

I dont know exactly what is done; But many a person has upgraded them to the standard of a 70. The G should have had the 70's HP, & I am sure I read engineers were working on it because the HP was too close to the A JD . I think You can put a 70 head on the block; change the carb. I know that would help some; But I am sure there is more that needs to be done.

JDseller · Jul 4, 2011

Like PopinJohn stated that you will be limited with the all fuel pistons. If you can find a set of 45 over OEM pistons they will balance better. I worked for a dealership that the owner was the lead mechanic during the late 40s and early 50s. He could always tell when someone had put aluminum pistons in a two cylinder. He would just lay his hand on the frame rails. You can feel the difference in vibration. The aluminum pistons are not as smooth unless you spend big money and have the engine balanced.

Anonymous-0 · Jul 4, 2011

when it was overhalled,was the cam redone? if not would be a good place to get back to fact specks. 486 head will help a good bit. the 486 head will help a quite a bit.maybe a set of petronics will help also,if nothing else makes it easer to start,even in pooring down rain. good luck dan

jd b puller · Jul 4, 2011

Scotty, you're a little confused...

The stock bore of the 70 was 5.875", the stock bore of the G was 6.125". The 70 GAS head will NOT bolt to a G block. The 70 AllFuel Head will. They are very expensive and hard to come by though.

The stock G was a gutless wonder, when compared to the cubic inches (413 vs 321 of an A). That's due mostly in part to the low compression.

Bolt the flat head on for a quick HP increase.

E=mail me for more.

Anonymous-0 · Jul 4, 2011

are you sure that you got your story straight? I have a stock 51 B and it dynos at 34 hp.

bill mart · Jul 5, 2011

I think most model B tractors left the factory at around 27/28 hp at the belt. Bill M.

rankrank1 · Jul 5, 2011

(quoted from post at 04:42:47 07/05/11) are you sure that you got your story straight? I have a stock 51 B and it dynos at 34 hp.

Last model years (i.e. 1950, 1951, and 1952) of both the JD model B and the JD model A were made in gasoline only versions so they had higher compression and thus more hp from the factory than earlier models which were all-fuel models.

The G was never made in anything but all-fuel versions from the factory. The last model years of the JD A had almost the same hp as the JD G, but the A had less torque than the G. Of course many people installed aftermarket high compression pistons in their G's and made one powerful plowin tractor that liked its gas.

DP · Jul 5, 2011

1947 and up A's and B's could be gas or power fuel from the factory. The G was never offered as gas. Your cheapest up grade without breaking the bank would be aluminum pistons and a gas manifold. Increased HP will be noticed. If you are going to be working this tractor for more then just pulling or something of that nature, you will want to add a water pump if its not new enough to have a factory pump on it.

JLG · Jul 5, 2011

I'd 2nd the alluminum piston idea. Usually you'd have to clean up the bore's, but since you just overhauled it 4 years ago, I would think you could slide in a set of .045 over M&W's and be fine. When I bought mine a few years ago they were $450, and came with rings, and wrist pins. Then it's another ~$115 for a head gasket, manifold gasket, lead washers, and silicon, so you can do the swap. I did that to my 1950 "G", then later added the cold manifold, and a reground camshaft. It's now 58hp on the dyno, and a different machine. I can easily pull 3 16's anywhere around here. It ran warm until I put replaced the fanshroud that was missing when I bought the tractor. Now it's fine, even plowing all afternoon on a warm day.

Anonymous-0 · Jul 5, 2011

Yes look in the books. . .i work for Deere and we dyno tractors on a daily basis. The G only produced 38 belt hp but the torque is way higher than a JD B. Twice the cubic inches and alot longer stroke.

Mike Eneboe · Jul 5, 2011

Thanks to all for the helpful replies. These old tractors are a change compared to this new stuff we work on everyday at Deere. I have had a few two cylinders in the past, and enjoy them very much. This G is the first one i have considered adding more power to though. It is has all the correct parts and does run very well but i feel it should run better considering the size of the engine and the tractor. Likewise, if anyone has questions regarding New Generation on up to our current 2011 models, feel free to ask!

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