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Pinion angle adjustment

237
2
Hey guys,

I have a 13 boss .. oem ride height .. i recently installed a bmr upper control arm with its mount and the lower control arms with their relo barackets.

Whats the angle on the angle finder that i should adjust the car to ? ... what i did was adjust it to 0 from the lower flat side of the pinion flange

The lower and upper control arms have pollt bushings

Thanks
 

302 Hi Pro

Boss 302 - Racing Legend to Modern Muscle Car
2,009
438
Southeast
I see you also posted about a rear diff leak.

The pinion angle should be -2 to -2.5 degrees.

Remember, the pinion wants to jump upward on WOT starts from standstill. You want to limit this upward thrust movement to a max of a 0 degree setting or slightly negative setting is best.

If the angle goes positive, it will bang, and shutter, this could affect the crush washer and cause pinion bearing seal failure.

Let us know what you find.
302 Hi Pro
 

TymeSlayer

Tramps like us, Baby we were born to run...
3,765
2,666
Exp. Type
HPDE
Exp. Level
3-5 Years
Brighton, Colorado
My car is lowered on FRPP T springs with BMR UCA and LCAs and run -2 degrees. She responds well. Can't really say with stock springs.
 
237
2
But the video on bmr showed that they set the angle to 0 ...?

Can you give me basic english step to do it correctly ??
 
237
2
From what i understood which i did was ...

First i measure the angle of the transmission which i took from the flat piece of metal attached between the engine and transmission, this showed me an angle of -2.

Then i go to the lower flat plane of the pinion flange ( im not sure if this is called pinion flange but its the thing which bolts to the end of driveshaft and is connected to the differential ) and adjust the angle there to 0 degree assuming that with polly bushing i have 2 degree movement upwards when accelerating at wide open throttle.

I found that the angle finder was pointing to 3 or 3.5 degrees with the differential pointing upwards so i lowered it to 0 degrees assuming that when i go wide open throttle the differential would rotate upwards to 2 degrees with the pinion pointing upward.

Please help me out i got no one who can help me out here im in the middle east.
 

302 Hi Pro

Boss 302 - Racing Legend to Modern Muscle Car
2,009
438
Southeast
eng90 said:
From what i understood which i did was ...

First i measure the angle of the transmission which i took from the flat piece of metal attached between the engine and transmission, this showed me an angle of -2.

Then i go to the lower flat plane of the pinion flange ( im not sure if this is called pinion flange but its the thing which bolts to the end of driveshaft and is connected to the differential ) and adjust the angle there to 0 degree assuming that with polly bushing i have 2 degree movement upwards when accelerating at wide open throttle.

I found that the angle finder was pointing to 3 or 3.5 degrees with the differential pointing upwards so i lowered it to 0 degrees assuming that when i go wide open throttle the differential would rotate upwards to 2 degrees with the pinion pointing upward.

Please help me out i got no one who can help me out here im in the middle east.

When you type 0 degrees, I take this as the pinion gear shaft and the drive shaft is in a straight plane line.

The pinion angle is actually measured against a vertical line between the engine and bell housing attachment line. This is difficult to do. You can Google this method.

The noise of the pinion shaft must point downward when properly set, with the chassis loaded or settled at its normal ride height. Sitting on the tires, do not attempt this with the car on stands and the rear diff hanging.

In simple terms, the angle of the trans output shaft to DS is the near opposite angle of the pinion shaft to DS.

The DS points down from the transmission, and the DS points up from the pinion shaft. As mentioned above, the Pinion shaft should never torque upwards past 0 degrees.

302 Hi Pro
 
237
2
302 Hi Pro said:
When you type 0 degrees, I take this as the pinion gear shaft and the drive shaft is in a straight plane line.

The pinion angle is actually measured against a vertical line between the engine and bell housing attachment line. This is difficult to do. You can Google this method.

The noise of the pinion shaft must point downward when properly set, with the chassis loaded or settled at its normal ride height. Sitting on the tires, do not attempt this with the car on stands and the rear diff hanging.

In simple terms, the angle of the trans output shaft to DS is the near opposite angle of the pinion shaft to DS.

The DS points down from the transmission, and the DS points up from the pinion shaft. As mentioned above, the Pinion shaft should never torque upwards past 0 degrees.

302 Hi Pro

Sorry man i didnt get what you r trying to explain.. this is my 3rd language and if you can explain in simpler and basic english on what steps should i do to properly set the angle adjustment ?
 

302 Hi Pro

Boss 302 - Racing Legend to Modern Muscle Car
2,009
438
Southeast
eng90 said:
Sorry man i didnt get what you r trying to explain.. this is my 3rd language and if you can explain in simpler and basic english on what steps should i do to properly set the angle adjustment ?

Eng90:

I admire your linqustics skills! I too have questions as to the meaning of some of the terms you have used in your above post.

Please send me a PM with your contact and location information and perhaps we can schedule a phone or Skype conference.

All the best,
Dave
302 Hi Pro
 

TymeSlayer

Tramps like us, Baby we were born to run...
3,765
2,666
Exp. Type
HPDE
Exp. Level
3-5 Years
Brighton, Colorado
I went to my friendly Grease Monkey and measured while in the sunken pit with the car fully loaded. Not sure he was supposed to let me do it but he was a Mustang freak and allowed me access. It was the only way I could measure and tighten up with the car fully loaded. I suppose you could do it on ramps or with the tires on blocks as well.

From the BMR Instruction manual for adding the BMR UCA:

Make sure the rear end is loaded by either setting the car on the ground or letting the car rest on jack stands positioned under the rear axle. In both cases, the car needs to be as level as possible and the suspension loaded.
• Place an angle finder on the rear portion of the two piece driveshaft and record the angle. Now place the angle finder on the pinion yoke and record the angle. • Subtracting one angle from the other results in your pinion angle (Example: -2 rear end angle subtracted from 0 driveshaft angle = -2 degrees) • Adjust the control arm to achieve the desired angle. • As a starting point, most cars respond well to the following initial settings: Automatics: 1-2 degrees negative, Manuals: 2-3 degrees negative • Once pinion angle has been set, apply Loctite to jam nuts and tighten.
 

576

Tremec has a nice app that walks you through driveline angles. Provides a good starting point.
 

576

App store. Search "Tremec driveline angle finder". Your phone becomes the tool. Has speed, rpm & tire size as well. :)
 

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