Drive shaft frame clearance

[JGRacing]

I have seen it mentioned that the u-joint on the drive shaft should have 1 1/2 inches of clearance from the frame on a dirt track.  My rear frame height is 4 3/4 inches from the ground, I dialed back the pinion angle to 1.5 degrees, yet I can only get 1 inch of clearance without the driver.  Is the 1 1/2 inches with driver, or am I missing something? 

[bback58]

You don't want 1 1/2 inches of clearance.  I think all the guys around here want as much pinion angle as they can get and have the U-joint pretty much rubbing on the lower frame bar.  Mine has worn a little groove in the frame where it rubs once in a while.   When mine is sitting without me in the car it damn near rubs.

[VMS Motorsports]

Ditto what brian said...my frame beneath the driveshaft has been hammered out of the way so I can have ANY clearance...still hits at times. need all the forward bite/pinion angle you can get

[JGRacing]

The frame looks like it has had a few run ins with the u-joint.  I figure at 250 lbs it should get more clearance when I climb in.   

How much pinion does everyone run?

[djracing]

As much as I could get into it

[VMS Motorsports]

The driveshaft clearance modification technique aka "sledgehammer"

[JGRacing]

I might try that "adjustment".   

[justfreaky]

Jim,

That looks like quite the tecnical operation.

Steve 

[VMS Motorsports]

It works...bet I got an extra degree of pinion angle, sorry I couldnt come up with a more technical term for it, but hey, it's a picture, so you gotta be happy Steve!

[justfreaky]

Oh Yeah, Love those pics!!! 
Was that a few well placed blows with the sledgehammer.............................
Or, did you use the Lizzy Borden approch and give it 40 whacks?

 

Steve

[VMS Motorsports]

a little bit of each...they do make these things pretty sturdy, so the "precise adjustment" approach was less than fruitful

[justfreaky]

Do you use a short handled, or long handled sledgehammer?

[VMS Motorsports]

Short....are you done yet?
 

[justfreaky]

I was just interested in the technical aspects.

[justfreaky]

I wonder why they don't "C" that area, or drop it down just a bit?
I suppose it is to limit suspension travel or pinion angle.
I will have to look at that when I mount the rear end. I don't think I will need as much pinion angle as you dirt guys.