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Setting pinion angle when welding spring perches on??

RyanG85

RyanG85

Well-Known Member
I just got my 8.8" axle back from having the axle tubes shortened and now its ready to weld the spring perches on. I plan welding them with the same pinion angle as the 8" I removed but before I do, I thought I'd check with the pros here. Is there a better way?
 
I'm no expert but I'd go for the specific angle you want and then if needed Summit sells angled shims. You could adjust if you get driveline vibration.
 
Kinda how I figured. I'm no expert either hence this post. I figure go with the same as stock and have some shims on hand. Never hurts to ask though..
 
my understanding is that it should match the trans angle to prevent vibration. I know some racers tweak it for hard launches so as to not break u joints so they set it up based on what the axle would be under load.
 
I'd just set the axle on top of the perches and leaf springs, use your angle gauge to get it close and then have a buddy tack the perches to the axle tube. The alternative would be to use a hydraulic jack to position the pinion at the angle you need and then tack the perches to the tubes yourself. I've read that you don't want it at a perfect 0° because then the u-joints won't wear at all. I'd shoot for 1.5-2° driveline angle differential if it were me
 
Ryan, FWIW, I set my rear pinion angle in exact relation to the tranny pinion angle.

But I can also adjust mine through my 4-link suspension too.
 
I've got the perches tacked on right now in the exact position as the 8" that was in before. I'm gonna assemble and recheck before I fully weld. I think they will be fine where they are.
 
I'm surprised the shop narrowed the housing and welded the bearing ends on before the perches were welded on. Welding the bearing ends on (in the jig) is the last thing I do when setting up racing housings. Welding other stuff on warps the tubing and puts the bearing housing out of alignment with the spool (in my case) centerline.

Anyway, I flop everything down on the perches on top of the leaf springs and approximate the angle match with an angle finder, then clamp the u-bolts down and load the springs and re-check. A floor jack under the center is fine for checking. A straightedge across the housing face transmits the data to the angle finder. A couple of times back and forth and it's done. Tack the perches, remove the housing, weld them, then into the jig and weld the bearing ends on. I'll point the pinion down 1-1.5 degrees on a performance application.

If the housing comes in to be narrowed only and not set up any special way, I just blueprint the prior angle in the perches before cutting the ends off and match it up after narrowing, then weld them on, then weld the bearing ends on.

Remember, when checking, imagine a line drawn through the centerline of the crankshaft and a centerline drawn through the pinion shaft, both longitudinally. Those are the parallels. Everything references to that.

Good luck :)
 
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