Farmall A piston weights

TWheat · Aug 17, 2009

I was reading some IH engine piston info(from years back). Was stated that the Farmall A pistons were all within 1/4 oz in weight. How important is that? what if one or two were heavier(or lighter)? Just wondering, I had never run into a piston weight question

glennster · Aug 17, 2009

you want the pistons as close as possible in weight. keeps the engne in "balance" and doesnt vibrate. if the weight variance is too great of an amount , the motor can shake itself apart.

TWheat · Aug 18, 2009

Thanks Glenster

Janicholson · Aug 18, 2009

I'll ad to Glennster's comment.
The crancks in many inline four cylinder engines are of the two up, and 2 down variety. This has no intrinsic ballance, but depends on the mass of the system to be uniform to keep vibration to a minimum. Though the actual weight of the piston is not critical (within reason), the uniformity between the pistons is very important. If the two up pistons weighed more than the two down pistons there would be pretty radical vibration. Imagine a barbell with a half pound missing from one end.
Thus the use of a cast iron piston set in early engines could be as smooth as a set of aluminum pistons in a replacement set without any ballance problems, and no changes to the crank or pulleys or flywheel. JimN

Farmall A piston weights

TWheat

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glennster

Well-known Member

TWheat

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Janicholson

Well-known Member

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