How much abuse can these units take(I have a 91Z)? A friend of mine just put a set of stickes on his car and cut a 1.8 60'(w/a mustang). I am leary to do the same because I have heard these units are weak? What are my options? How much abuse can a stock unit take? How much would a rear cover girdle help? Thanks Derrick

 

i've heard or read welding the axle tubes and a girddle add 40% more strength to it. hard to say for sure, some people have really pushed theirs and other have broke them with stock engines. i put a 450 plus hp in my sons car and the rear end help up with street tires. if you want tp up grade and don't mind the cost take a look at moser 9" rears for the f body.

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ICON Motorsports
1st & 3rd
MM Black Diamond 538 F&AM

 

Strange is also making brand new 12-bolts for our cars,if you're spending some real money,and you can avoid putting Ford parts in it.
-Rich-

 

My car still has a 10 bolt. LPW rear cover, welded tubes, solid crush sleeve and aftermarket 28 spline axles. No problems yet.

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Follow my racing progress on Stephen's racing page
and check out the race car

87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block (times are for the current engine)

Best ET on a time slip: 11.447 altitude corrected to 10.99
Best MPH on a time slip: 119.42 altitude corrected to 124.86
Altitude corrected rear wheel HP: 493
Best 60 foot: 1.586

Racing at 3500 feet elevation with a typical race day over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

 

anyone else? Thanks guys Derrick

 

Stephen 87 IROC

Wow that's impressive, but what do you mean by solid crush sleeve. Is that the collapsible weird looking washer that is located on the pinion gear? If it is why is it better if it is solid? What material is it ....mild steel?

Sorry for all the questions, but these sound like a fairly simple mods to increase the strength of the 10 bolt.

Bill

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1992 Camaro Z28 L98
1997 K2500HD 6.5TD L65
1998 Yamaha WR400F
1988 Yamaha FZ750
1985 Yamaha RZ500
1999 Ski-doo MXZ600

 

I also have the "crush sleeve eliminator".... it's a piece of steel tubing basically. It comes with a set of shims, which you select to attain the correct bearing preload. One of the ways that these rear ends die is that the crush sleeve crushes a little more with use, which takes the preload off the bearings, which allows the nut to back off among other things; the bearings wipe out, and the pinion isn't held in the correct orientation to the ring gear, so they wipe out.

I had a 400 with a big roller cam and a good set of heads etc. in my car; I've only trashed one 10-bolt in 300,000 miles so far (by breaking the carrier in half, incidentally). IMHO the weakness of these units gets too much press, when in fact if they are well set up and taken care of, they aren't all that bad.

The stud girdle definitely helps. Another thing that happens to rear ends under heavy load is that the case spreads out, which also allows the R&P to misalign. The girdle-type cover holds the case in the right shape. Plus, the ones that have the cap struts, also keep that possible source of gear misalignment from occurring.

Did I mention misalignment of the ring & pinion as being a major cause of death? If not, consider it mentioned... the same thing goes for any other gears, they'll last alot longer if the castings that hold them together can do their job.

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"So many Mustangs, so little time..."
ICON Motorsports

 

Ok w/that said...what et(or 60') can be obtained with a stock unit before i have to worry about it breaking? Thanks Derrick

 

Ok w/that said...what et(or 60') can be obtained with a stock unit before i have to worry about it breaking? Thanks Derrick

 

What RB83L69 said about the crush sleeve is correct.

The way the ring and pinion are designed, they want to go out the back of the diff on accelleration. The solid pinion spacer won't collapse like the stock type crush sleeve. This will keep the pinion from moving and applying more force on the factory type crush sleeve possibly crushing it more.

The rear cover with bearing cap supports helps keep the ring gear from wanting to go out the back. The support bolts apply 5 lb. torque to the bearing caps. This is all that's needed to keep the caps from flexing.

305's doing 2.xx 60' times can break stock 10 bolts. It all depends on how much abuse is put to the diff. High rpm clutch drops can easily break off pinion teeth.

 

Blowing up 10-bolts is pretty common over on LS1.com and usually the following is what kills them:

M6 car on a sticky tire. High RPM launches will kill them if the tires hook too.

A4 car on a sticky tire with gear ratio greater than 3.42

Street tires usually won't hook up enough to kill a rear end. Drag radials eventually will. ET Streets is living on barrowed time. Slick w/10-bolt is bomb waiting to go off if the car makes any real power.

The band-aid's like covers and crush collars are just that band-aid's. The 10-bolt has small gears. As the ratio (number of teeth on the gear) increases the amount of metal in each tooth becomes less as the teeth get smaller. Most 10-bolts the gears break if it's especially if it's a 3.73 or 4.11

Auto cushion the shock so 10-bolts last longer in auto's most of the time. Auto's usually have 3.23's which have more metal in the teeth so they are a tad stronger.

2000-2500 rpm launches on street tires seem to be ok on 10-bolts for the most part for M5-M6 cars...at least for a while.

[This message has been edited by Arctic White 91 RS (edited October 09, 2001).]

 

great artic that is exactly what I was trying to find out...thanks guys you have been a great help!!! Later Derrick