Someone set me straight.

NEKS

Well-known Member
Just heard today that all B JD's did not have petcocks on the cylinders. A's and G's did. Grandpa had a early styled B and it had petcocks you closed after starting. If B's had them they were installed later. Set me straight. Thanks
 

Maybe not "All" of them did, but I bet "Most" of them did..
Would have been stupid not too...!!

Can hardy believe, the 60/630's didn't have them from the factory..

Ron..
 
If I remember right they may have done away with them on the very late models. If they did there would be a plug where it would have been. You could remove the plug and install one if needed. My 52 A had them on the bottom of the engine. I don't remember the 1950 model B I grew up with having them but never looked under it. One thing not many are aware of is the B had a conversion kit that allowed for 2 Batteries under the seat.
 
FSB 178, April 1951 said that compression relief cocks were no longer being supllied on A,B,G tractors as they not of general use, and as an effort to conserve copper (Korean War), but they could be ordered as replacement parts if required, so pipe plugs were installed into the machined ports. I THINK that early "B"s did not have them added into the block until l ater, but there is mention of an improved design being introduced in '39. A different angle attempted to blow the fuel and oil away from the tractor.
 
Unstyled B's did not originally have petcocks. There is a flat spot on the side of the cylinder that may have been drilled & tapped later to add them. My '37 B with original low compression pistons cranks very easily with out them. Not so on my '44 B with gas pistons, it needs the petcocks.
 
My 1937 and 1938 unstyled B tractors do not have them, and the block is not drilled and tapped for them either. My 1951 B does have them, but I hardly ever need them.


Kurt
 
Best I recall the Unstyled 38 and older had them, but in 39 when they styled them they also increased the bore and resultant compression and thats when they added petcocks, i.e. beginning with 1939 Styled.

John T
 
My Grandpas 35 doen't have them. My 48 didnt have them but the block is tapped on the bottom for them. Had to install some when we bumped up the compression. The bottom one are a pain to use and always drop oil when you open them.
 
My '50 B has them on bottom.Only used them once when float hung open and had to purge raw fuelout before starting. New float had to "find it's home", never did it since.
 

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