Pinion angle ?

plymouthman · Dec 8, 2016

OK folks ,
I know that this had been asked many times before and I'm opening a huge can of worms by asking because I will get so many different responses. But I really am confused.
I finally got to set up my suspension.
Here's what I have.
73 rr , 8.75 rear , 4:11 posi. Ladder bars , coil overs. 440 backed with a 727. Factory locations including the trany cross member. Ladder bars are in the middle hole of 3 in the front, 1 up and 1 down is what I have for adjustment . My pinion angle is 3 degrees nose down. My drive shaft is 1.5 degrees down at the pinion.
If I raise the pinion much more it's gonna level out my driveshaft and put it into my driveshaft safety hoop.
Am I ok with what I have or do I need change it ?

plymouthman · Dec 8, 2016

plymouthman · Dec 8, 2016

747mopar · Dec 8, 2016

What's important is the relationship between the tranny and pinion angle but you want some angle at the u joints for longer life. Ideally you want the centerline of the drive train to run parallel with the pinion centerline, for example you would want your tranny facing down 3 degrees and your pinion up 3 degrees (parallel). That's in a perfect world, you may have to compensate for axle wrap but it's still a good starting point. Check your drive train angle by checking the degrees off of the crank pulley, bellhousing face or any other machined surface that is machined true to the centerline. My guess is your tranny will be somewhere around 3 degrees down.

I did a lot of research on this while trying to track down a nasty driveline vibration eventually finding it was my pinion angle. Good luck

plymouthman · Dec 8, 2016

Thank you.
I forgot to check the trany angle :BangHead:

,
I will have to check that.
Everything I've read about ladder bar suspensions has told me to set it up at 1 to 3 degrees. Am I correct in my thinking that I have 4.5 degrees sense both angles are down.

hangn0ut · Dec 9, 2016

Pinion angle is the angle of the pinion relative to the driveshaft. Nothing else. Not the body or the ground or the transmission. As such it is only one measurement and is not added or subtracted from any other measurement.

dvw · Dec 9, 2016

A ladder bar drag car 1.5 down between the pinion and shaft. As long as the trans is close either way 2 degrees will work. Ideally zero at the trans. Street is another story. Ideally trans and pinion should be close to parralell . My car the trans points downward. To be honest I've run it with both the trans and pinion pointing down 1.5 degrees with no ill effeects at 150 mph. Ideal, no. But it has over 300 passes.
Doug

plymouthman · Dec 9, 2016

I'm heading to the garage now. I will re check it all with my angle finder and post my findings. Not sure of the trany but like I posted in my original post , the driveshaft is 1.5 degrees down at the rear pinion and my pinion is 3 degrees nose down. All at ride height. No interior in car. Does not have the hood, bumper's or one fender on it yet either. Guess I should put those on first then then check.

69L48Z27 · Dec 9, 2016

We always ran ladder bar cars between 3-4* down. 4 link cars .5-1.5* down.

If the engine and trans mounts are stock location just concentrate on the pinion angle.

dvw · Dec 9, 2016

plymouthman said:
I'm heading to the garage now. I will re check it all with my angle finder and post my findings. Not sure of the trany but like I posted in my original post , the driveshaft is 1.5 degrees down at the rear pinion and my pinion is 3 degrees nose down. All at ride height. No interior in car. Does not have the hood, bumper's or one fender on it yet either. Guess I should put those on first then then check.

Need to check it at ride height loaded with drivers weight.
Doug

plymouthman · Dec 12, 2016

Thank you for all the responses.

Pinion angle ?

plymouthman

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