45 Flathead Belly Numbers

[bmh]

Rub, still think somethings a little fishy, crankcases were only available as sets according to the 54 parts book. Were they available separately in years prior?

[bselph]

Since we are talking about belly #'s, my 33VC has the following: 112-30F right side and 112-30H left side. What does the F & H mean?

[Rubone]

Brian,
Yes, they were. And I am not sure where you are getting your information as my original '54 parts book lists the crankcases individually available by side!
Robbie

[Rubone]

bselph,
Why does your '33 have '30 cases? Are your numbers original?
Robbie

[bmh]

Sorry Rub, I had the wrong parts book open on my desk the other night, you are correct, my mistake. I didn't look at the part numbers , only saw that no single cases were listed.

[Perry Ruiter]

Since we are talking about belly #'s, my 33VC has the following: 112-30F right side and 112-30H left side. What does the F & H mean?

Those aren't your motor's belly numbers. Those are the mold casting numbers ... Perry

[bselph]

I will check for other numbers tonight. My vin appears to be original stamping.
Thanks for the help.

[Chuck#1848]

I will check for other numbers tonight. My vin appears to be original stamping.
Thanks for the help.

You will most likely need a drop light and a mirror to see the numbers but the should start with the year of the bike followed by the mating numbers

[bselph]

Thanks guys. Matching belly #'s 33-3460 and serial # 33VC33_ _. Looks like I have a correct engine and the numbers fall within flat-happy's 125 employee theory.

[flat-happy]

Thanks guys. Matching belly #'s 33-3460 and serial # 33VC33_ _. Looks like I have a correct engine and the numbers fall within flat-happy's 125 employee theory.

please don't take my theory as fact though as i have no way of proving it. i was just going by what a guy told me who used to build engines for the factory. i doubt there is anyone working at the moco now who could back up that information but i haven't seen anyone tell me any other theory of the correlation between the vin and machining numbers either. we may never know now

[knuckleheadtim]

I don't think it's likely the belly numbers were attained by adding or subtracting the employee number from the VIN for several reasons:

1) It would allow for duplicate belly numbers; IE

4487 + 150 = 4637
4517 + 120 = 4637

2) Many early engines I've seen have a belly number lower than the VIN. I have a very early '38 motor with a high '37 belly number. As the year progressed, the belly numbers are closer to the VIN because replacement cases were sold without VIN numbers stamped. By the end of the year, the belly number is much higher (over 1000 in '47). At some point, they would have crossed, but not necessarily matched, since the motors weren't likely taken off the rack in numerical order to build bikes.

3) Three different stamp sets were used on each motor; the year on the belly, the 4 or 5 digit belly number, and the VIN number. This suggests the belly number was put on the matching cases and the VIN added after the bike was completed. The belly numbers were indeed stamped to identify a machined set. but they wouldn't assign a VIN to replacement cases.

[bmh]

I've seen at least one 49 motor where the belly numbers were higher than the serial. These things weren't kept in any order on the shelves any more than anything else. I highly doubt that any part of the VIN was placed on the case until the motor was ready to be married to a frame at the production line. If the VIN was present what was the purpose of the "7"'s stamped at the rear mount on FL motors? You'd be able to tell if it was a 74" or a 61" motor by the VIN.