alternative to welding diff.
 

I go to VC Tech in Alabama and one of my instructors made me think for a second on a subject that I have been pondering. First, here is the scoop on my car. 91' rs, 355 with eagle h-beam rods, forged mahle pistons (flat-top,) pistons zero with block deck. Vortec heads, larger springs, 3 angle valve job. Edelbrock performer rpm air gap. 650 holley carb. LT1 cam. Roller block.

Custom built th350 with B&M transkit. Also has manual shift kit. TH350 built by myself with a couple of free mods done that I know of.
Now for my question. I am in the middle of building my 9 inch and dont have the money for my ladder bars right at this moment. I have the stock 7.5 rear in it right now with stock suspension. I was planning on welding up the spider gears in old fasion but my instructor brought to my attention another solution. I dont plan on racing but mabye 2 weekends untill I get my 9 inch done. Heres the tip.

Instead of welding up the gears, how about shimming the side axle gears enough that it jams the axle gears into the spider gears, thus locking it up. But when the toque on the rear gets too critical, the spiders would allow the axles to move independantly causing no axle or gear breaks?

It sounded pretty good to me. This is a race only car, trailered and all. No interior except cage and seat. Also trans has a 3200 stall. No trans brake. I run in footbrake class. How does this sound to ya'll?
Sorry for the long post but really need the help. Season opens April 2nd. All help is appreciated

Daniel

Doesn't work. All you'll accomplish, is destroying the side gears and spider gears from the misalignment. It won't produce a "posi" effect. You'd be lucky to get 5 ft-lbs of breakaway torque out of it, and even if you did, it wouldn't last more than a couple of seconds after the first time it "broke loose".

If this is a throw-away that's only going to hit the track a couple of times, and you can deal with it being near impossible to drive in the staging lanes and in th epits and whatnot, and it NEVER EVER hits the streets, just weld up the gears and throw it away afterwards.

Thank you for the reply. I had never heard of anyone doing this and the instructor that told me hasnt done it before either. He was just throwing out an idea. I will fire up my welder when I get home and install a lincoln locker this afternoon. Thanks, Daniel

I had a 7-1/2" diff welded up real good. It was more than I wanted to attempt so I had a welder do it with some good welding rods. I ran it for a couple of years until I finally installed a 9" with a spool and never had any problems with the diff.

What your instructor was hinting at was a replica of a chezzey fNord limited slip unit. In the 8.8's and a few others they use a Z spring and a very small clutch pack on both sides. This creates a posi effect.
|\|-Z-|\|, it still retaines normal spider gears which is nice, but it will not lock under heavy load its more of a last ditch effort on ice and snow kinda thing.

i didn't think that welding the spider gears was IHRA/NHRA legal...

I don't think it is.....but they'd have to pull the diff. cover to find out.

HipHop.....click here we need some more thirdgens in the local club. I'm providing two and there are a couple more that show occasionally but otherwise I'm getting lonely. :D

They wouldn't have to pull the cover. Somebody that has seen it alot (like the tech guys at the track) can tell if its welded up by the way the car drives, and no welded spider gears aint legal.

A lincoln locker IMO just aint smart. Sure it was done in the 50's 60's and 70's when the parts wasnt around. It aint safe, it aint strong, it will break parts, etc. You may even loose your car cause of it (crash)

I say throw a $300 locker in it. Like a powertrax lock right, or a EZ locker, etc. If you get a diff rear later, you can pull out the locker and keep it for later use, or sell it for around half price. Lockers are very hard to damage, so selling a used one, wouldnt be too hard

I dunno if I'm gonna get slammed for this, but maybe a spool or mini-spool? I'm not into the kind of motorsports you're into, so I dunno if that would accomplish what you want. But for my sport alot of people on a budget like running welded diffs. I dont really believe in that because I wouldnt consider it reliable, but what I do believe in is a mini-spool. Alot of guys into dirt track racing run those, and I'm gonna try em for my sport and see what happens. I dont know how expensive they would be for a 9 inch, but I do know the mini-spools for our stock 10 bolts are under $100, and they'll completely lock the rear both forward and back at all times. I'm gonna be installing one of these into a stock 10 bolt I got for $20 pretty soon here. Not cool for a daily driver, but should be OK for a track car. Knowning me I'll want to sample it on the street too.

They wont know you welded the gears and Ive never seen any tech demand you pull the cover to prove to them what you did. Hey buddy I got a spool.

CH brings up a good point a spool is dirt cheap and easy to install.

yeah, a welded diff and a spool will drive the same way. the spool is legal, the welded diff is not. 10 bolt mini spool is $99 from jegs.

I would run a mini-spool if I could but I have a stock (except gears) 7.5 , my car is a 91'. The only mini spool I have been able to find is one for 26 spline axles and mine are 28 spline. I wont put a locker in it because I dont have 300 dollars to throw around on a rearend that will be coming out mid summer. I am in the midst of building my 9 inch and I need something that will just hold for the time being. Thank you.

I will check out the club in t-town. My camaro is track only but I might have seen ya'll. I run up at Holiday.

The club is Birmingham based, my wife and I just drive up from time to time.

I've been to Holiday a few times, but not on a regular basis. I used to go to Steele pretty often but the track is in real rough shape now...

Yeah you're right, they dont make the mini-spool for the 28 spline axles. You could do the $99 SLP drop in posi (which is basically an OEM 4th gen posi), but thats not gonna lock it like welding or a spool so probably not the way you'll want to go. Another idea is to goto a yard and get some 26 spline axles out of a stock 3rd gen 10bolt. If you got hookups you can get em cheap. I got an entire 10 bolt (26 spline axles, diff, and housing) for $20. You could probably sell the 28 spline axles here on TGO to someone looking to go the SLP route and make your money back. I wouldnt normally recommend going with the weaker part (26 spline vs 28 spline), but considering your situation it might be a good idea.

I had thought about going to the 26 spline, but something feels real odd about me goin to get 26 spline axles to replace my 28 spline axles in my race car. Something about that just dont sound right. Im gonna try and find out some prices though. Its only for mabye a month of duty, Thanks guys, Daniel.