CLASS RACER FORUM - 12 Bolt Chevy problem

CLASS RACER FORUM (https://classracer.com/classforum/index.php)

- Stock and Super Stock Tech (https://classracer.com/classforum/forumdisplay.php?f=4)

- - 12 Bolt Chevy problem (https://classracer.com/classforum/showthread.php?t=19442)

Re: 12 Bolt Chevy problem

some really good points that you sometimes overlook because you get tired of looking..yes I have a good cover/girdle,but yes I am also guilty of sanding the pinion gear for easier removal.my other car has a dana 60 that has all that stuff & never had problems ,but shim is also behind the race too.I will try that with the 12-bolt & see.as far as pre-load,Ive never measured it,just went by feel,and have used from "snug" to "tight",,I probably should actually measure it....as far as the pinion to bearing fit,I have some Green sleeve retaining loctite,will this help,plus maybe some carefully placed light center punches work to hold it in place?..I really appreciate all the answers & suggestions,if there are any more,I'll gladley listen as it will still be a couple of days before i start back toegther with it...........Thanks so much,Vic.......P.S. I also have some converter questions I'll ask in another thread if anyone wants to help

Re: 12 Bolt Chevy problem

Quote:

Originally Posted by Kingpen (Post 133108)

Ive been fighting a problem with keeping pinion shims from coming apart & out.car is a 95 camaro stocker but I run it in SS with SS motor.weighs 3400lbs with p/g & 99% of the time it is foot braked.it has a Strange housing ,which I figured would be better for making things last longer,but after 50-60 runs,it will start making noise & when I check,the shim is gone.this has happened 3 times in the last 2 years.I use the ratech collar instead of crush sleeve and always get pinion depth within .003-.004 of what is written on gear.Pinion nut is still "tight" from the loctite but of course has some slack from the lack of shim.The nut backing off doesnt seem to be the trouble as I have marked it before to see if that was the case.any ideas,suggestions(dont want to change housings),something I am missing???got lucky this time and didnt hurt gears,not so in the past....let me know............thanks Vic Penrod

Vic, we have run twelve bolts for years with high horsepower engines etc. I set up the gears and have a lot of experience and proper tools to get it done. I machined billet heavy duty caps for the spool bearings,
made my own solid design pinion spacer that used a shim along with front and rear holes to allow gear lube to flow thru machined tubular spacer. The spacer seemed to always show signs of loosness when tore down. MY Fix, pinion has ran five years now with no spacer between the bearings. If you want to try this always use a new G.M.pinion nut with heavy duty loctite, tighten nut to intended pinion preload and let set a day or two before running the car for loctite to harden. I use a 40 inch pound torque wrench to
set the preload, it was designed to set the preload on jet engines and was military surplus when I bought it
Good luck on fixing the problem, Ray

Re: 12 Bolt Chevy problem

V ic,

Give me a call at 650 922 0407

Bob

Re: 12 Bolt Chevy problem

on the "sanded bearing" idea...i have a used but in good shape bearing that is polished (sanded) to be able to tap it on and off for setting the pinion preload and clearance, then once the proper shims are selected i remove the bearing and install a new one. bearings have a high tolerance from one to the next, as long as you use the same manufactuer and p.n. each time you shouldn't run into clearance changes.

Ian