LP pistons in tractor

NEKS

Well-known Member
A fellow told me that the last time they had their Farmall 400 overhauled they had LP pistons put in it and it upped the HP to 60 over horses. Didn't know they made such a thing or is this guy blowing smoke.
 
If he is claiming they are OEM LP pistons he is blowing smoke. The Farmall 400 used a different head and the same pistons as the Gas burners. Actually the LA Case did the same thing also.

I own both of these tractors on Factory LP.

jt
 
My dad has a 44 MH that was an LP, but was converted to gasoline before he bought it, still had the LP pistons in it. But he said it didn't want to turn off just kept wanting to go, just what he told me!
 
Many companies used to sell high compression pistons for replacements.
M&W add power was the most popular.
 
Early 400 used a gasoline head with a dome for LP. Later 400 and all 450 Lp used a special small chamber head and flat top piston.

Tractors built to run on distillate or kerosene used flat top pistons with a large chamber head to lower compression. Now 60 or so years into this and with those two fuels gone from use, most of these old tractors have been rebuilt with some kind of domed piston for increased compression
 
Gasser pistons 6.33 to 1.LP pistons 8.33 to 1. Your neighbour may have forgot to tell you that they pulled the dry sleeves and are running over size pistons.
Given that a stock 400 made 50HP. I would believe 60HP if the sleeves were pulled and LP pistons used. More if they knew enough to get the worn cam ground with a modern profile and followers trued up. A three angle valve job, blend the rough edges out of the valve bowls and match the ports to the manifolds. She would be pushing 70HP. More yet if the rpms were dialled up to 2100-2500.
How else would a" stock " M built as such are so popular with pullers.
 
IH made a lot of piston types back then no longer made. After that I think IH just started using fire crater pistons for replacements. At one time you could get them for higher altitude, + more compression. High altitude and some LP pistons in the 400 and 450 era were step head design to raise the compression. 400 came with 4 inch bore sleeves and not long after they were selling the 4.125 bore kits for them.
If the person installed say a 8000 foot piston or other combination that would raise the HP.
At one time lots of different piston and sleeve sets were sold for C-264 and C281 engines. Not counting distillate and kerosene or SM and SMTA engines. 400 used 2 different cylinder heads for LP, early and late, late also used on C-281. 2 different piston pin sizes. Early LP head was the same casting as a gasoline used on 400 and 450.
IH tests on a 400 engine equipped with fire crater pistons obtained right around 60 HP corrected to sea level. That engine was tuned to go out work continuously. Use of higher octane fuel and tuning on a dino could result in a 60 HP reading depending on what else is done to the engine. Depend on who interprets the dino readings also.
 

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