MTFCA Forum

I’ve read some on the earlier forum about Dunn counterweights. Seems like a good idea to me.
As long as they are fit properly I would add.
What do you think ?

Stole this pic from the old forum...

I ran one for a quite a while. I dont recall any problems, in fact I liked the smoothness @ speed. I think the motor finally needed new Babbitt, & i went with a Scat crank. The idea of a possible failure had me nervous.

Several issues I addressed:
The ones I had were NOS. They are made to fit the "non improved" beaver tail crank throws. I wanted to run the later crank, so some grinding & fitting was necessary.
All hardware was replaced with grade 8. Weights are installed so the O.D.'s of the weights match. As an additional safety measure I figured I should pin the weights to the crank. I used 2 long 1/4" allen bolts. Counter bored head, thread into opposite weight, tight in line hole thru crank. Every hole edge chamferd. All locktited.
Replaced in a lathe to perfect the counterweight O.D. with a clean up cut.
Balance.

There were made to quickly bolt on. A racer buddy warned me about them coming loose. I took the extra effort to insure they wouldnt move.

I have been running a set since 1978 on my 27 roadster. I spent a LOT of time carefully fitting them so they could not come loose or impose any bending strain on the crank.
The fitting effort is essential!

I have 2 votes for the good...
Has to be a few more opinions.
I have a few sets, I am thinking about trying a set when I get around to my rebuild. The rest I will probably pedal.
Can anyone tell if they are originals ?

I have seen both types. The repops seem to have a coarser surface. Originals are fairly smooth. The script is proud & clear. (Looked at mine)
Those pictured I'd bet are repop based on the appearance of the lettering..

The key is in the fitting!!
It is critical that they are clamping securely without applying ANY bending forces to the crank!!