Moparts

pinion angle

Posted By: RapidRobert

pinion angle - 12/11/22 11:28 PM

63 dart 360/904/7&1/4 circle track. I am raising the eng/trans so I can fit good flowing magnum ex manifolds. what is the max degrees offset I can use? I know I want the degrees pretty close but in opposite planes. I do have angled shims for the rear axle as needed. Thank you for your time. RR
Posted By: CMcAllister

Re: pinion angle - 12/11/22 11:35 PM

O boy. The pinion angle subject.

First question is - which u joint is closer to the ground, front or rear?
Posted By: dvw

Re: pinion angle - 12/12/22 12:22 AM

5 degrees wouldn't scare me. Shouldn't matter which end is higher.
Doug
Posted By: RapidRobert

Re: pinion angle - 12/12/22 12:48 AM

I will check/measure further. I've definitely jacked up the eng quite a bit to try & run these manifolds. thanks guys. RR
Posted By: gregsdart

Re: pinion angle - 12/12/22 08:01 AM

The motor and rearend can be offset quite a bit, as long as the pinion angle is set within reason, no more than 5* down, or less. I used a Ford 8.8 in a 65 dart i built, which was out of line side to side by 2+ inch?
But the differential and engine were parallel side to side, about three degrees down pinion angle. 500 hp 408, no problems.
Posted By: RapidRobert

Re: pinion angle - 12/12/22 02:12 PM

Good info, I will get after it. RR
Posted By: CMcAllister

Re: pinion angle - 12/12/22 08:00 PM

Originally Posted by dvw
5 degrees wouldn't scare me. Shouldn't matter which end is higher.
Doug


If you're trying to make the pinion and crankshaft parallel, it does. You do NOT want to run the pinion angle up (negative) in relation to the driveshaft C/L.

If the engine/trans is angled down (front u joint lower than the front of the crank C/L) that doesn't change. It just needs to be adjusted around to get the best compromise. A million backhalf cars out there like that.
Posted By: RapidRobert

Re: pinion angle - 12/12/22 09:26 PM

more good info, thank you. RR
Posted By: moparx

Re: pinion angle - 12/13/22 07:20 PM

if the pinion angle is angled up, it will wrap "up" more under acceleration, and vibrate bad.
beer
Posted By: dvw

Re: pinion angle - 12/14/22 02:50 AM

Originally Posted by moparx
if the pinion angle is angled up, it will wrap "up" more under acceleration, and vibrate bad.
beer

Pinion can be up if it's less than the trans is down in the rear. My racecar is 1/2 degree up. But the trans is 2 degrees down.
Doug
Posted By: moparx

Re: pinion angle - 12/14/22 08:07 PM

you are correct Doug.
i meant that to mean if the combined angle was up, [the pinion angle up higher than the transmission output shaft down] it would wrap up more under acceleration. sorry.
beer
Posted By: Cab_Burge

Re: pinion angle - 12/14/22 08:51 PM

Originally Posted by dvw
Originally Posted by moparx
if the pinion angle is angled up, it will wrap "up" more under acceleration, and vibrate bad.
beer

Pinion can be up if it's less than the trans is down in the rear. My racecar is 1/2 degree up. But the trans is 2 degrees down.
Doug
What angle is the pinion shaft V in relations to the drive shaft?
The longer the driveshaft the less angle there is there, correct?
Posted By: jwb123

Re: pinion angle - 12/14/22 09:54 PM

The most efficient transfer of power is a zero-pinion angle. When there is no angle on the u-joints, it spins smooth, the more angle the more the driveshaft has to speed up and then slow down while rotating. Lock an older 4-wheel drive truck and turn it hard you will feel the pulsations in the steering wheel as the axle rotates.
When building a race car, you set the at rest pinion angle down a few degrees so that it comes to zero under hard acceleration. Leaf springs are hard to estimate but 5 to 7 degrees is what I use and 2 to 3 degrees for 4-link and ladder bar.
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