Deenasty

First question:
Well I am currently running a spohn tq, bmr adj phr, hotchkis lca's.(12 bolt rear also) You know the bracket from the tq arm, that attatches to the rearend, has 2 sets of holes. One set for a 12 bolt rear, one set for a 9 inch. Did any of you cut this bracket to eliminate the 9" holes, or vice versa, and eliminate the bracket from hitting the underneath of the car? Someone told me that I need to do this.

2.) I went to get my pinion angle checked today, and it was way off. Partially because I have a lowered car, and no lca relocation brackets. Well We were going to adjust the pinion angle, but the person doing it said that I needed to get the relocation brackets first. I agreed. The thing that sucks is that I am running a BMR extreme duty rear sway bar, and the damn saddle brackets are already welded to the rear! So now I have to cut them off I guess, and set the correct pinion angle, and buy new saddle brackets and have them rewelded.

Any advice will be greatly appreciated! Thanks Guys!

LPEdave

The LCA relocation brackets have no bearing on your pinion angle. I'd adjust it before you damage something...

Dave

Injuneer

I'm a bit confused by most parts of this post...

1. The extra set of holes in the rear mount is on the part that faces the pinion... how does cutting the extra holes off make more room? Are you sure you are using the correct set of holes for your application?

2. LCA's do not set pinion angle, only the torque arm controls this. Since when you lowered the cars, the angle of the LCA's probably went from slightly below horizontal (axle end below body end) to slighty above horizontal (axle end above body end) the change in length was negligible. In any case, is isn't going to affect the pinion angle all that much, since even if you went from below horizontal to "level" the change in axle position is less than 0.10" and the torque arm angle isn't going to change enough to make resetting the pinion angle necessary. You will find that since you dropped the front TA mounting point when you lowered the car, and the centerline height of the axle remained the same, that the pinion angle was affected. But adding LCA relocation brackets has no affect whatsoever on this.

3. Why do you feel you have to remove the saddles for the sway bar? That controls absolutely nothing related to pinion angle. If you rotate the pinion slightly to correct the pinion angle, you would need to check the side-to-side delta height preload the sway bar is providing, but you adjust that with the end links.... not by cutting the saddle off the rear and rewelding them.

I don't see any "disaster" here... I'd say the pinion angle wasn't set correctly to begin with.

And it is TOTALLY misleading to use a "topic" that might suggest to some that the Spohn TA somehow caused a "disaster". It's simply irresponsible.



Given the amount of mis-information you are getting, you might want to think about finding a different shop pto do your work.

NOSCaMaRo

When I first read the thread, I didnt think the heading was saying it was spohns fault just that he had no idea how to set pinion angle, lol.

Like already mentioned, the reloc. brackets have nothing to do with pinion angle, just the torque arm. The adjustable torque arms make this easy to adjust so a shop that knows what they are doing should have no trouble.

Deenasty

Ok i guess my horrible explanation has got everyone confused.

1. Here is a picture of the bracket for the Spohn Torque Arm. I drew on it, has anyone cut this off, in order to make room to stop the bracket from hitting the bottom of the car?
TORQUE ARM

2. Here is a pic of the saddle brackets I am talking about.
saddle brackets

Since the current pinion angle is at roughly a +6, the yolk is pointing towards the sky, and the saddle brackets were welded on, the saddle brackets current position looks like this.
saddle 1

After the pinion angle is set correctly, and the yolk is pointing a slight bit down (roughly -2 or -3) the saddle brackets position will move like this correct?
saddle2

Follow me now? SOrry for the bad drawings. I am getting the same response for the lca relocation brackets, so I guess they wont be a problem..Should I Set the proper pinion angle, then have the relocation brackets welded on? Thanks Guys hope i makes more sense now..

LPEdave

Dang that's a seriously clean car!

I see what you're saying about the saddle brackets, but adjusting the pinion angle should change the rear end something like 4 degrees, and the swaybar will just rotate in the bushing. I really doubt it'll be an issue.

Dave

Deenasty

I hope that it is not an issue, because I was pretty scared when they said I had to cut off the brackets and reweld new ones

I will set the pinion angle correctly today. LPEDave, have you ever adjusted the pinion angle this way:

1. put angle finder on front face of cylinder head, and jack the rear of the car up until it reads 0.

Then go underneath, place the angle finder on bottom of the tq arm bracket, and set it properly.

And your done?

LPEdave

I've heard two ways of adjusting pinion angle, and frankly I'm not completely clear on which is most relevant. They're definitely different though. The method you describes conceptually aligns the output shaft of the tranny to the same plane as the pinion in the rear. That's making an assumption that the front face of the cylinder head is known to be perpendicular to the output shaft - I didn't know that was supposed to be the case, but I guess it could be.

The second method is the one I describe on my web site, which is also what most of the f-body suspension manufacturers suggest, which defines the pinion angle to be the angle between the pinion and the driveshaft, and has no relation to the transmission. Setting the angle here is something that makes sense (to me) based on a drag launch. Setting the angle with the first method is a way to minimize both the front and rear u-joint angles on the driveshaft, and probably makes more sense for overall balance and longevity of the u-joints.

I've never done it the way you suggest, but would be curious as to how the pinion angle as measured the second way reads, if you set it up.

Dave

Deenasty

where is it on your site? Also, I noticed you welded your lca relocation brackets a bit off. I was afraid of doing this also. Is there anyway of knowing exactly where to weld them up? Thanks..

LPEdave

I've got instructions at http://www.go-fast.org/z28/pinionangle.html

As far as the brackets, I think the best bet is to make sure the rear axle stays in the loaded, stock position through at least to the point where the brackets are tack welded. Ie, before removing the stock LCA (do one at a time) get a jack stand under the axle so that when you remove it, the axle doesnt move. Then slide on the bracket, re-attach the lca into the bottom hole of the bracket, and tack the bracket in place. Then pull the LCA out to do the rest of the weld. Repeat on the other side.

Dave