Flathead cam case woes

[montuckymatt]

1937 flathead U model. In the process of assembling my bottom end. I installed the new cams with endplay set at @.007-.010. It spins over with the cam cover installed but there is a ever so slight amount of drag it seems like. I pulled the cam cover and can see the scavenger pump drive gear move up and down slightly as it rotates with the spiral gear. With the cam cover off it still has the slight amount of drag, leading me to suspect the spiral gear or scavenge pump gear.When I tore this motor apart the old spiral gear had a couple of sheared off teeth. I assumed it was from the pieces of wrist pin keeper that went through the bottom end. Maybe not. None of the cams are binding and the wheels turn freely without the scavenger pump/spiral cut gear installed. Any help appreciated on where to go from here.

[JBinNC]

Does the scavenge pump turn freely once it is installed in the case?

If it is free, that would suggest that the drag is coming from the drive gear. Maybe try a different drive gear or breather gear to try for a better fit?

Jim

[DustyDave]

I work on a different brand of antiques but the are booth antiques. Sometime when the worm gear distributor / oil pump drive is tight even after going threw all my quality spares (Junk?) it still fits too tight a thin coat of fine lapping compound and a boring afternoon turning then washing carefully then checking feel usually gets it to the point it is good enough or I have to mark the high spots for further attention. When it's made of unobtanium you just gotta do more hand work.
Dusty

[Dragstews]

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[montuckymatt]

I ended up finding a used one that worked perfectly. Who would have ever guessed
A repop gear that doesn't work without modofication.? Lol...
Ah well, maybe over the winter I'll use your suggestion and lap it to fit as a spare.