74'' VL balance factor

[Pete Engelman]

I am helping a fellow member assemble his 1934 74'' VL engine.
I am not sure if a 74'' VL falls into the flathead category or JD category but does anyone know what the flywheel balance factor is for a 1934 VL. We also need the crank pin, pinion and sprocket shaft nut torque values?
Thanks
Pete:::::::::;;;;;;;;;;;;;;;

[T. Cotten]

By any stroke of luck, Pete,...

Are the flywheels still assembled, and the piston assemblies saved?

Their actual existing factor could be calculated.

For what that's worth...

...Cotten

[Pete Engelman]

Thanks Cotten
No it was all apart, he has a new piston kit and they weigh in at 505 grams the same as a standard cast 74'' shovel piston. I'll ask if he has the originals but he never mentioned having them. They have been drilled with 4 1/2'' holes at the 06:00 o'clock position on the pinion wheel and 2 1/2'' holes in the sprocket wheel at the 04:00 o'clock position. I think I'll use the 60% factor S&S recommends in the balancing kit instructions.
This one could be a little tricky
Pete::::::;;;;;;;;

[Steve Slocombe]

Dear Pete, I think the high balance factors are used on late model Harleys so they can blat around town at low revs. The early Hints and Tips book implies 50% balance factor when it says halving the piston weights in the calculation. I've been using 46% balance factor on the VLs for a while with good results, and one builder goes a shade lower. Little metal is removed from paired flywheels, so this must be close to original. Note that flywheels balanced for cast iron pistons are stamped C on the outside and you probably don't want to mix these with the stock unmarked ones.

On torques, Harley just said 'very tight' on these nuts. I take that to mean around 100 pound-feet on the sprocket and gear shafts, which have locks in any case. The torque on the crankpin nuts is used to set the end float of the rod assembly in the flywheels so I might go up to 150 pound feet here, and again the nuts are locked. The VL is a flathead and the JD a pocket valve, and literature is available on both.

[T. Cotten]

One reason the factor was different, Folks,...

..Is because the frames are different: http://virtualindian.org/Flywheeltheory3.htm

Unless a reasonably unmolested assembly can be found and back-calculated, we are just conjuring.

Graciously, factor is enormously forgiving.

....Cotten

[Pete Engelman]

Thanks Steve and T.
I appreciate the info. I used 55% on my generator Shovel and 60% on my cone Shovel. I thought the difference in balance factors was due to the width of the rotating assembly and the fact that HD put that big heavy compensator sprocket on but I suppose the pinion and sprocket shafts are still suspended at the nearly the same distance from the flywheel on most models. I saw the very tight torque value in my 59-69 service manual as well. I am glad you mentioned that the crank pin torque dictates the end play which will be very helpful knowing we can as high as 150 ft/lbs.
Thanks
Pete::;;;;;;;;;;;;;

[T. Cotten]

FIve points difference in factor only shows how forgiving balancing is, Pete!

Its a little sad however, that we may never know what the factory considered ideal,....

Just because nobody took the time.

.....Cotten