1946 U female rod width at crank pin

[slamiste]

Hi all,

I'm doing a rebuild on a 1946 U. When I disassembled the engine I noticed that there was excessive side play (+.060") between the rods and the flywheels. I had the rod race bearings fitted to the existing crank pin (which was in very good condition), replaced the thrust washers in the flywheels with new ones and assembled the crank assembly today. I still have +.060" of side play. The specification is .006" to .010". I have no history on this engine. It seems to me that I've either got an out of spec crank pin or the width of the female rod have been reduced for some reason. I measured the width of my female rod and believe it to be +/- 1.745". To help me sort out what the issue is do any of you know what the actual specified width of the female rod should be.

Thanks!

[exeric]

A friend of mine had the same problem with a late Indian Chief. The crank pin came from one of the major aftermarket motor part manufacturers and gave him the same problem you have. He compared the new crank pin to what he presumed was an original and there was a considerable difference. He chose not to use it and got another one from a different source; problem solved, except he was stuck with a useless crank pin. I assume a wider crank pin would also show itself at the thrust washers for the drive, pinion shaft, and combined side play accumulation.

[slamiste]

Thanks Eric,

Yeah, it's most likely the crank pin or the female rod has been modified from some far in the distance past rebuild for some reason. I agree the crank pin is the more likely scenario but it would be nice to know what the rod width is supposed to be so that I don't spend any more money than necessary.

My AMCA number is 3978. I joined the club in 1986. Looks like you joined quite a bit earlier.

Steve Slaminko

[koanes]

The rod width is correct. Do you have original flywheels using the stepped pin? I haven't run into any extra long stepped crankpins, but have had some later pins that were too long. I have been using the two hole extra heat treat pins from Eastern and they have been working well.

[slamiste]

Thanks Kyle,

The flywheels are original and I'm using the stepped crank pin. This engine had it's last rebuild in the early 8o's and as I mentioned, it had very few miles on it so the existing pin was still usable. I don't know the origin of the crank pin but it's a single oil hole example.

If the rod width is correct then it's likely the crank pin. I also try and use Eastern products so I'll go ahead and order one in the next day or so.

Thanks again!

[slamiste]

Hi,
Even though it's been a couple of months now I just put the flywheels together with a new Eastern crank pin and that took care of the problem. Since you guys were so kind to offer advice I thought I should close the loop on this subject.

Thanks again!

Steve Slaminko