Both lash and crush are adjusted by inserting and removing shims behind the carrier bearings. Lash is the amount of play between the ring-and-pinion gear teeth. It can be adjusted by changing the amount of shimmed distance between the left- and right-side carrier bearings. The total amount of shimmed distance sets the crush, while the manner in which the total amount is split between the two bearings sets the lash. The process of getting both of these amounts correct is quite labor intensive and usually requires installing and removing the bearings and shims several times. Because of this, Ingram uses a set of setup bearings that have been ground on the inside diameter to allow them to slide onto the locker easily without having to be pressed on. You can do the same with a set of old bearings and a hand grinder.

On a new rearend, Ingram normally begins by inserting 0.034 inch worth of shims on the left side of the locker and 0.056 on the right side and adjusts from there. With the setup bearings in place, install the assembly into the left-side bell and install the centersection on top of that with no gasket or O-ring.

Ingram checks crush by placing the right-side bell and tube in place with three 0.010-inch shims between the centersection and the right-side bell. These shims should be spaced equally around the centersection. Press down on the bell using only mild force. If there is still space even with the spacers, some spacers will need to be removed from behind the bearings. You can tell when you don't have enough spacers behind the bearings if the right-side bell rocks after removing one of the 0.010 spacers. When everything is perfect, the 0.010 shims should fit the gap between the centersection and the bell perfectly. Also remember that you will lose crush on final assembly if you are using a set of setup bearings, so try to err on the tight side.

Once the crush is correctly set, reassemble everything (with four bolts holding both bells to the centersection) and check the lash at the pinion gear. Before setting up your lash gauges, spin the gear several times to make sure there are no rough spots from a bearing hanging up. Check the lash at four places in 90-degree increments on the pinion gear.

Ideally, you want between 0.008 and 0.010 lash at the pinion gear. If the lash is too tight, remove some shims from the ride side of the locker or spool and add the same amount to the left side. This will move the ring gear away from the pinion. If the lash is too loose, you can move the ring gear closer to the pinion by removing some shims from the left side of the locker or spool and adding the same amount to the left side. Remember, you should never change the total amount of shim distance because this will change the crush. You only want to move shims from one side of the locker or spool to the other.

Once you have the correct amount of spacing for both crush and lash, remove your setup bearings and press on the bearings you actually plan to use. For peace of mind, check both your crush and lash again to make sure nothing changed when you added your race bearings. If everything is correct, you can begin final assembly. If not, start over, but use the race bearings. Install your tube seals if necessary. Insert O-rings between the bells and centersection, along with a thin film of silicone, and torque the bolts into place. Finally, set your wear pad adjuster. You can do this by threading the adjuster all the way in until it makes contact between the wear pad and the back of the ring gear. Then back off on the adjuster a quarter of a turn.

The last step is to reinstall your rearend cooler, if you run one. Then get everything back underneath your race car and add your gear lube. In all, a complete rebuild should only require a couple of hours and can save you from a lot of heartburn at the racetrack.

SOURCE
Tiger Rear Ends
7-04/-636-7029
www.tigerrearend.com