pinion angle

[flyinlow]

3rd gen  ,440,727, 8 3/4 (3.55)

I swapped original 318/8 1/4 for  a mildly built 440/ 8 3/4. Installed new Mopar H.D. springs.

Using a magnetic angle gauge , the engine and driveshaft downward angle appear the same. (front ujoint straight)

The pinion appeared to be 2 deg. less down angle than the driveshaft. (as pinion rotated up under acceleration angle would go to zero or negative)

I added a 4 deg. shim to make the pinion more nose down. Driveshaft /pinion angle now 6 deg. with car sitting on ground.

Is this correct?  Car behaves well under hard acceleration, nowheel hop.

[firefighter3931]

No worries...as long as there is no vibration you got it right. I allways try to shoot for 4-6* nose down when setting the pinion angle. 


Ron

[flyinlow]

Thanks Ron,


I am working on a cycling noise at 55-65 mph. Level road , maintaining speed noise sounds like a twinengine airplane with the props not synced.

Noise goes away under acceleration or coast.

New drive shaft,was balanced.


When I put the  8 3/4 axle in lastmarch. I used the7260 flange that the pumpkin was set up with. In May I installed the 440. I had a driveshaft made

using 7290 joints. I pulled the companion flange off an other carrier I had and bolted it on the 742 carrier in the car. Did not check reload. Car has

been driven 2500 miles this summer. Couple trips to drag strip. Many burnouts at the Mopar Nationals. Started noticing noise about 1000 miles ago.

[firefighter3931]

I would re-check the pinion nut torque....it could have backed off affecting the preload adjustment. When someone describes a whine from the centersection the first thing that comes to mind is backlash adjustment. 


Ron