Help on a new John Deere Model A rebuild-horsepower

I grew up on a farm in the 50-60's. All we had were Johnny Poppers, and still do (all G's, and 1 B). Anyway, even though I didn't much care that my Dad and Grandad made my brother and I repair the old JD's, today, I am very thankful for the memory and knowledge.

I now have 5 children, of which are three boys. I am working them through a complete rebuild, even if they don't like it too much. They will like the sound, i would bet.

I found a 1949 Model A (has an all-fuel manifold) in a junk yard, don't know how long it had been there - but I got it home and i did get it unstuck. Really rough, but a complete rebuild is doable and I'm commited.

My questions:

1. As I understand it, The A's were middle ground between a G and a B. My dad and grand-dad kind-of frowned on the A's, and I never knew why as I liked them and there sure were plenty in service near us.

I don't want to turn this into a competition puller (would actually like to work the ol 30a combine, baler, etc). I would like to add an additional 10 horsepower relatively easily. Preferably without the bore, but will if recommended.

Will going to std bore. high compression pistons, gas manifold, distributor (vs. Mag) get me what I need or close? If not, how much can I get by buying off the shelf components (buying easy horsepower) without firing up the machine shop to bore and mill and modify. Ideally, I would love to have 40 horsepower.

2. Is any modification of this sort, a trade off to durability? Again, I want to work it a bit (not hard, but consistant). And would like this to be operational for a decade or so, without tearing it down again to the crank.

3. It has lights, but no alternator/generator. Did they go to a 12 v system by this time, or am I looking at a switchover to a 12v system. is this a pain?

Thank you all, in advance, for your comments. It is very helpful to me.

High comp pistons and a gasoline manifold ought to give you 10 easy.

M&W book says "A" Deere on gasoline 584,000 and up is 38 hp. with M&W piston .125 overbore will give you 44.3 hp.That would be raising the comp from 5.6-6.5.

There was a 1947 Nebraska test with an AR that had 38 horsepower, which would likely be a gasoline manifold engine. You could check the tractor pulling sites and choose from the low-cost options available there.

Your 40 hp goal should not be a problem. The A would run the 30a combine and a 14T baler easily, and pull a 3-14 plow a lot of places.

You would want the high-compression (high altitude) pistons, the gasoline manifold, and a distributor. If you change to 12 volt you'd want an electronic ignition module. Have the carburetor redone, and use the insert bearing rods from a model 60. There was an optional water pump for late A's.

The 1949 tractors had electric start and lights and a generator, all based on a 6 volt positive gound system.

You will need the optional water pump for what you intend. Burning straight gasoline, heavy pulling, PTO loads, etc., they tended to overheat, especially as they aged.

Thank You all, very much.

OK, So I am excited now that I might be able to drive over to Dad's and put a chain to his 46 or 37 G. No bore, and I think ~ 38-40 horsepower.

Good grief, now the juices are flowing. Is 50 HP within easy range, or, are stepping into money and more radical upgrades (kindof makes me think that at some point, you have to consider the crank and rods durability)

So, this is what I just digested from your comments, and a few more questions if You don't mind.

1. High Compression pistons and gas manifold.

Question: Going higher compression, leads me to think that I will likely be advancing timing. If I remember correctly, timing on the ol g is 25 deg BTDC. If this is true, can I do it by ear or to truely dial it in do I have to find a dyno somewhere?

2. Distributor: It has a mag on it. Is the switchover easy (bolt up) to current governer body, add coil, etc? Is this a common upgrade?

3. Water pump: Our ol G's were notorious for overheating (even on Tractor fuel!), no real surprise here. Is this also a common upgrade wherein I can find an upgrade kit and simply bolt on the pump, add the pulley, and modify the cold water return? I just tried to find this kit, and I must be lame in my searching.

4. Are these types of upgrades the types of things You would do even if You were not going for much more horsepower, but just to take advantage of current fuel, technology?

I plan to keep this tractor in the family from here on out. Want to stay close to originality, but not completely married to it. I want to have fun and work it a bit (work on these = fun from me).

Thanks again, to all of You for your comments, in advance.

Back in the late 50's and early 60's, when we
converted our G J.D.'s from gasoline to propane,
we installed a "flathead" cylinder head from
J.D. to increase compression for more power.
I don't know if they were available for the
model A or not.

If it is a 1949 then it allready would of been 12 Volt when new.
If you do have an all-fuel manifold then it may of been a low HP all-fuel model and just putting in gas pistons will make it where you want it. If you can find some add power pistons put them in. For 50 HP a power block will be needed.
And by all means put a Delco dist. on it. You won't need electronic.

a"s came with twelve volt systems when they went to the pressed steel frames in "47

No need for the waterpump. If the radiator and block and head are clean you won't overheat it. Make sure it has a good rad. cap on it. I can put my '41 A with a Power Block on the Dyno all day long and it doesn't got over 200 degrees, those cooling systems are fool proof if you keep them clean.

No, that head was from the early G and fit on the late G but A & B never had a flat head.

Brand new radiator will cause them to overheat. My 51 A had the 4 tube orignal radiator go bad and the radiator shop got a 3 tube and after that 3 tube was put in had to get a water pump for a late 52 and put on and then was OK but that 3 tube will not cool as fast as the 4 tube type. This was before the Chinese stuff at 25+ years ago.

The carb was different on the all fuel from the gas tractor. Go to the JD parts site and you can print out the parts books and with that you can see what all has to be chainged for gas from all-fuel but they do not have the newer aftermarket pistons listed with a higher compression rate.

If you need to have any machining done on your original crankshaft.. you may just want to go to a Stroked crankshaft and avoid the problems and expense associated with a "power Block"..
JDBPuller (Extreme Parts) can fill you in on how much stroke you can use without even cutting the Rods, or..he can do the work..
I think he has a New Head, for the "A"..!!

Ron..

Timing will be More critical with more compression.

You most likely will not be "advancing the timing"..
Detonation shatters Rings..(and about anything else, given enough time)..!

Ron.

If you are going to use it hard on a hot summer day a water pump will be a must at 40 HP. But if it pulls a baler you might not need one. When we used to row crop cultivate with our 51 A with a power block and water pump it would have trouble keeping it's cool on hot 90-95 degree July days. We were in fourth gear wide open laying by corn with a four row cultivator. We'd have to shift down to third gear where it was under maybe a 60% load to let her cool down. We could lug it all day long in the spring and fall without it getting hot.

Dad had the power block put in when the tractor was only a couple of years old and the dealer told him he'd need to have a water pump to cool it on hot days. The dealer was right. Jim

gas manifold, #71 carb and some M&W pistons would liven it up, beware of the performance parts from someone mentioned here. Many of these parts are in the design/experimental stages and have not been proven long term. You would not want to stroke a tractor for what you are doing. I wonder if someone here is a paid spokesman for extreme tractor parts, ps- early a&b tractors did have a flat head

Can a fella install 60 LP pistons in a stock stroke late A? A buddy of mine did that to a 44 A, made a nice healthy tractor out of it, but, its a hand cranker!!