MM rods in a 55 massey???

Kyle Ladowski · Aug 16, 2011

Does anyone know the dimensions of some of the larger Minnie Mo rods? Possibly the MM U rods? I thought someone told me that they put U rods in their MH 55 and could offset grind the crank some. I am having a problem getting pistons made for my 55 because the distance from the center of the piston pin to the top of the piston is 3.625, the forging will only take a max of 4.520 bore and that is only .020 oversize on the bore. I'm not sure my sleeves will clean up at +.020. It has been suggested to get longer rods and or stroke it some to get the piston shorter so I would have more options on the pistons.

Any ideas? I'm not looking to go pulling much, maybe a few times a year, but would still like to be able to do some plowing with it.

Thank you,
Kyle

Goldsburg · Aug 16, 2011

Kyle -

There is no good answer for this problem Kyle. It is likely that any rod that is long enough to make an available piston work will have a crankpin bigger than the 55's. You could stroke, but even with a smaller rod journal, a 7" crank gets really tight against the block in the area of the starter indentation and doesn't get you to an acceptable piston pin height (with a stock rod).

My honest advice is to carefully remove the sleeves and send them off to Darton, LA, etc, and have undersized replicas made that can be bored back to "standard" to fit your pistons and a new set of rings.

To get a little more power out of your 55, you should first look at the carburetor then turn your attention to a camshaft. Shaving the head for a slight bump in compression is another low cost option.

If you want to discuss anything in further detail, send me a message through the site.

Regards,

Goldsburg

Mopower · Aug 16, 2011

A U rod is 10" with a 2.5" rod journal.
A G rod is 12" with a 2.75" rod journal.

Kyle Ladowski · Aug 16, 2011

Thank you for the responses....I think I have three sets of pistons, one m&w set and two stock sets and the top ring lands on every set are so destroyed that you could just about get two rings in them. So I guess I really need to find some new pistons.

I will keep digging and see if I can come up with something.

Thanks
Kyle

north puller · Aug 16, 2011

I know that they are not cheap, but what about custom rods? If you could find a less expensive piston that would work then you could have a rod built with proper length and custom pin size? Have you tried murphy's for pistons? Surely if he can build giant deere pistons, he could build a 55 piston.

mEl · Aug 16, 2011

(quoted from post at 14:24:22 08/16/11) I know that they are not cheap, but what about custom rods? If you could find a less expensive piston that would work then you could have a rod built with proper length and custom pin size? Have you tried murphy's for pistons? Surely if he can build giant deere pistons, he could build a 55 piston.

Case rods for the 00-30-70 series have a 2.75 crank diameter and are 10.5 In/CL. Depending on diesel or gas there are different pin sizes.

I have an 830 Case diesel that the top ring lands were badly worn and I simply put them in my lathe and widened them to 1/8 from 3/32 and ordered 4 individual compression rings. this engine has been working faithfully for many years. Just think "outside the box" and many problems can be overcome cheaply. mEl

MM rods in a 55 massey???

Kyle Ladowski

Member

Goldsburg

Member

Mopower

Well-known Member

Kyle Ladowski

Member

north puller

Member

mEl

Well-known Member

Similar threads