39 a engine

kabat

Member
I recently got a 39 A that was just about gone. Major rust issues, engine froze up, wheels and rims rotted off. I welded new rims on. Put on tires, broke the engine loose. Now the rest of the tractor. I took the head off, and cleaned out the gunk. My question is. The engine has the original cast pistons with babbit stlye bearings. Will newer pistons and rods,{late A or 60} work in this 39 without a lot of major problems
 
Yes late style pistons and rods will work. If you are only changing to the new style pistons with using the 39 rods, you will have to enlarge the bushing in the rod to accept the pin. The new style piston pin is slightly larger in diameter. Not that big of deal, many including myself have made this modification.
 
Also remember the babbit style rods are more forgiving with the shims. If using rods with inserts, it may be a little more difficult to get the tolerances without crank work. If the crank looks good and you can get tolerances within reason using the babbit rods, I would stick with them and use new style gas pistons to wake up the power some.
 
the crank will need to come out and be turned. it looks like the new style rods are shorter, the piston pin hole is lower on the skirt. the way i see it, the pistons and rods both need changed
 
GTX is right. If you put gas pistons & all fuel pistons side by side they're the same height.

The piston pin holes however will be in different places!

Gas & all fuel connecting rods are the same but when pistons are attached to 'em, the distance from the center of the crank pin to the piston face is greater on a gas than an all fuel giving it higher compression.
 
so when i order parts do i need gas or all fuel pistons i really dont know what tractor i have
 
Mostly just your call. Gas pistons made of aluminum will make it much snappier. It will then be a gasoline only tractor. If you go original with all fuel iron pistons it won't have as much HP and will be able to burn most any petroleum product that will flow through the system long as your shutter still works. Sometimes they're easier to get to idle smoothly with gas pistons than with all fuel.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top