Just makes you say hmmmmm

Bkpigs · Sep 11, 2010

Took the head off the A and this is what I found. Apparently I am not the first one to be in there. Someone replace number 3 piston with a stepped piston (I guess that is what it is called). I am gonna leave it there unless someone sees a problem with it.

old · Sep 11, 2010

Are the other pistons different if so that can be a problem. If all the pistons do not match each other it can/will put an uneven load on the crank shaft and that in turn can cause the crank shaft to brake

Janicholson · Sep 11, 2010

Old is 100% correct. The pistons are a reciprocating mass that is balanced (not to the crank, but to each other. As two go down two go up. If they are within 2 or three grams of the same Wt, it would be OK, but I would replace them all. Even used pistons (All with dome) would be Great.
Jim

Bkpigs · Sep 11, 2010

CRAP!!! I was hoping that would not be the case. It makes perfect sense though. Do you think if I just replaced the stepped piston with a flat top it would be good or do you think I should replace them all.

I don't know how long it ran like this. I would sure hate to drop a couple more hundred bucks into this thing if it would keep goin the way it is.

old · Sep 11, 2010

You need one type or the other to be what it needs to be. Now depending on where you are I might have set of used ones here since I have 2 B engines and an A engine that are for the most part just a bunch of parts

IH fan · Sep 11, 2010

No doubt the compression is different in addition to the weight of the pistons. This will cause an uneven power stroke which can be as bad as the weight difference. Changing the one domed (or pop-up) to another matching flat-top would be okay, but you will need to change the rings and hone or change the sleeves on all so the compression is even.

ScottyHOMeY · Sep 11, 2010

As the others have laid out, it's all about balance. The difference in weight of that one piston isn't enough to bend or warp the crank, but it's had to have (or, with time, will have) played havoc with the bearings. Think of a flat spot in an out-of-balance tire. Your pistons have to be matched up reasonably close in weight.

Bkpigs · Sep 11, 2010

Old,

I am about 30 miles East of St. Louis. I would need one flat top piston. Also, if you happen to have the seat bracket (the half circle one that bolts to the axle housing) for a B that would be great. E-mail me with a price for each and maybe we can figure something out.
Thanks a bunch!!

Bkpigs · Sep 11, 2010

guess I should give you my e-mail [email protected] I thought I had it set to leave my e-mail open. Guess not.

Stuart · Sep 11, 2010

But if that cylinder made more compression would it not put more of a load on the bearings, and crankshaft?

old · Sep 12, 2010

I guess you know I'm down at the l;kae of the Ozarks Oh by the way my e-mail is always open on this site so easy to e-mail me. I'm sure I have either type of piston unless all 3 engines are the flat tops

old · Sep 12, 2010

An engine being run like that can cause all sorts of funny problems. It will be unbalanced it will be hard on rod and main bearings will most likely run with a funny sort of vibration and who know what else type of problems could be had

Just makes you say hmmmmm

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