Harley VL flywheel torque specs

[Buster]

I'm assembling a 1931 Harley VL flywheel. What do I use for torque specs for nuts on shafts and crankpin & rod end play. Are they the same as for a UL? Thanks.

[Peter Cooke]

I recently bought some VL flywheels from Truett & Osborn, asked the torque question, and got the following back. If it works for them, who am I to argue!


We use a process to assemble the flywheels that helps to eliminate false readings on the torque wrench.
We will tighten the nut, drawing the shaft into the taper fairly tight, then we press the shaft into the flywheel, then we re-torque the nut again to make sure it is secure. You will notice the nut will rotate another 1/32 or 1/16 after being pressed in, before you reach the same amount of torque that was used before pressing.

We use this method on the sprocket shaft, pinion shaft, and the crankpin into the right side (keyed) flywheel. It is not easy to press the crankpin into the left flywheel, because right flywheel is already attached. For this nut, we draw it in then take a socket that fits over the entire nut so it does not contact the nut and give it several blows with a lead hammer to help seat the taper, before we re-torque the nut.

Using the press in/re-torque method gets the shaft pulled all the way in without using extra force/torque on the nut to do it.
This way you know that the taper is drawn into the flywheel as far as it can go, and you can be confident the torque you are applying to the nut is not being used to pull the shaft in further.
This allows you to feel the point when the nut reaches a "dead stop". You know the feeling where you say to yourself "If I go any further, I am going to break something" Listen to this feeling but get it as tight as you can.

[Steve Slocombe]

Dear Buster, the original specification was 'very tight'. The shafts are 1" diameter so a bit smaller than the UL. I'd go 100-140 pound feet torque. The new crankpins can be a bit longer than original, and I think the Harley end float of the rods between the flywheels was specified on the tight side, so if you still have say 20 thou side float on the rod assembly with the crankpin nuts at max, I'd leave it there.

[Buster]

Good info, thanks!