TheSamba.com :: View topic

Sun Jul 29, 2007 6:23 pm

Found my gen pulley loose at a show last weekend, decided to tighten it up today before going out on an errand. Even with the impact wrench it still wouldn't get tight. I figured it needed more shims on the outside to allow the nut to put pressure on the outer half before bottoming out.

Taking it off, I realized that the outer half was "wobbly" as the striaght sided cutout was worn..... back half too.... and the hub was kind of munged up. I know this a common wear issue and when it exists, the pulley will never stay tight.

So I rifled my parts stash and came up with what looked like a very good 25hp pulley set and an NOS (tall) hub.

With an extra shim on the outside, I got it tight. But then I started wondering about the nut and went back to the gen parts box.

I have several thicker gen nuts, like the one on my gen, where the inner snout protrudes out past the back of the outer nut surface by about 1mm. Then I have some nuts that are much thinner. I know the fan nut is also very similar.

But can someone describe the "big" 25hp nuts unique characteristics? I assume the thinner nuts are fan nuts, and after the big gen pulley nut went away, they went to the smaller (27mm I think) gen nut with smaller hub and redesigned pulley. Is the big nut just thicker than the other 36mm nut? Are there only the 2 kinds of 36mm gen (and fan) nuts?

Mon Jul 30, 2007 12:10 am

All my pulley nuts have thickness of 14 mm and the center thread area is 16 mm. And I haven't had any tightening problems with them.

Mon Jul 30, 2007 8:08 pm

I can't believe you used the impact on this.

Tue Jul 31, 2007 7:36 pm

drscope wrote: I can't believe you used the impact on this.

Lightly. I can throttle back my impact wrench on the trigger. That, and I was tired of it coming loose.

Keep me from munging up the pulley halves by trying to lock it down with a screwdriver too....

Tue Jul 31, 2007 8:46 pm

small slots make for big nuts. big slots have small nuts,and you can "take it to the bank"

Wed Sep 05, 2007 11:11 am

Is this a 36mm generator pulley nut?

It is 17mm tall.

Wed Sep 05, 2007 11:20 am

EverettB wrote: Is this a 36mm generator pulley nut?

It is 17mm tall.

Looks odd Ev, the center barrel should be longer I believe. Can check when I get home. Perhaps others can confirm...

Sat Sep 15, 2007 7:26 pm

Here is an original Big nut and gen pulley hub Ev. See how the barrel extends down into the hub when installed. It also extends out beyond the bottom plane of the nut also.

Its 14mm thick as measured on the side also....

Mon Sep 17, 2007 8:59 am

Thank you

Mon Sep 17, 2007 3:27 pm

This weekend on a small zwitter shakedown cruise, the damned Big nut shook off, along with all the other parts. Luckily we were idling at a stop light. Drove it up onto the sidewalk to get out of the way and proceeded to fix the problem. Quite a crowd gathered to put in their two cents. While digging through my tool bag I realized that I didn't have my big socket. One of the by-standers thought I should use the vise-grips that were in my pile of tools. Then it came to me. The big wrench in my Hazet toolbox would work. And that it did. I may have paid a shitload for that box but it paid off. in tightening the nut, I couldn't get it tight. I think I may have lost a shim or two. We limped home and now have a 36 horse pulley in place which seems to work better. and all of those 25 horse pieces got buggered up so i guess I can throw them out. so much for correctness. but we have put 125 miles on it!

Dave

Thu Jan 05, 2012 7:49 am

I have a big nut generator lying around, what is the last year they were used?

Thu Jan 05, 2012 9:44 am

Mid-1955