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I am getting ready to take the go cart out for a test drive.Before I do, I want to get the pinion angle correct. I see that Tremec has a smart phone app to help. However, I am having a problem getting repeatable results. I can find consistent level line on my TKO 600 trans. I can eyeball the driveshaft fairly well. I cannot find a good level surface on the ford 8.8 rear end. as a result, sometimes the app says my angle is good and the next time it's off.
Anyone have any suggestions.
I've usually been able to use a square to align off the pinion yoke or flange so I can change the vertical surface to a horizontal one to align my level (or smart phone) with. I have sometimes had to use an undamaged socket as a standoff from one of the u-joint caps on the pinion yoke side. Worse case, disconnect the driveshaft at the axle and use a machined surface off the yoke or flange.
karlos
11-03-2016, 12:03 AM
This worked pretty well for me. The magnetic base will stick to the pinion flange even with the driveshaft installed. About $5 at harbor freight.
http://thefactoryfiveforum.com/attachment.php?attachmentid=55084&d=1466045464
http://thefactoryfiveforum.com/attachment.php?attachmentid=55082&d=1466045463
edwardb
11-03-2016, 06:43 AM
Debated about whether to post because it always leads to a "discussion." But pinion angle and driveshaft angle are talked about alot on both forums, with the two terms getting interchanged and maybe confused. Searching on the internet also shows the terms often being used interchangeably. Bottom line though is the driveshaft angle isn't needed to measure pinion angle. You're looking for approx 2 degrees difference between the engine/trans angle and the diff angle. Doesn't matter whether the car is level or not, what the angle of the driveshaft is, etc. Just the relative difference between the two measurements.
Easiest way to get the engine/trans angle IMO is right on the face of the crankshaft pulley/harmonic balancer. Easiest way to get the diff is on the pinion flange if the driveshaft isn't installed yet. If that's not available, then one of the ears along the side of the diff by the pinion flange. The engine/trans will typically be pointed down 1 to 1-1/2 degrees, and the nose of the diff also pointed down, the two adding up to the target of 2 degrees. I use a small digital level. Accurate to tenths of a degree and points to which side is high and low. Even I can understand that. I've seen lots of guys use a level meter like the one Karlos shows as well.
Having said that, the driveshaft angle is important. U-joints have a max angle that they're not supposed to exceed. But with the trans in relative alignment to the diff and the pinion angle measured as described, it is usually fine. I've looked at it, and I guess checking everything with the Tremec app is a good final check. But measuring the two angles as described is all that's necessary.
edwardb has done a great job of simplifying a subject that some of us can complicate. If you are designing from scratch or modifying an existing design to extract more performance then there can be more aspects of driveline design and set-up to deal with. But for most builders they really only need to worry about the pinion angle and its relationship to the trans output shaft angle, the engineer that designed the FFR car you are building would have took u-joint angle operating range into consideration. Back in the day when I went through factory training at Ford, the only thing a Ford mechanic was concerned with was adjusting pinion angle to eliminate vibration. The ideal pinion setting was one that had both the trans output shaft and the pinion shaft at the same angle under load. This almost always means the pinion angle static setting is adjusted with the pinion at a shallower angle as under load the axle will rotate and the pinion angle will change. The factory will have determined a static pinion angle that will provide for angular alignment under load with new suspension parts for each of their designs. Leaf springs and rubber bushings allow the most rotation under acceleration and will need more static misalignment than a three-link suspension but virtually all suspension designs will allow some axle rotation. That's why you will see settings that have the pinion angle set shallower by one to several degrees than the trans output shaft. You want both u-joints operating at the same angle under load to minimize vibration. The more you look at this and the more you play with hot rods you'll find that achieving perfect alignment is a moving target. That's one reason there are so many opinions on the subject.
Thank you everyone.
I loosened the driveshaft and was able to get my magnetic base in the surface of the pinion. I also found mounting the magnetic base on the harmonic balancer provided a good surface for getting the crankshaft/transmission angle.
Using my smartphone as a measuring tool was not as good as I hoped. I was able to get consistent readings with it but I didn't believe the numbers. I think the protective case caused it to tell me the angle was 0 degrees when my level said it was 1.5 degrees.
At any rate, using a square and a digital level I was able to get repeatable readings. I measured the engine/trans angle and pinion angle but didn't bother with the driveshaft angle.
Again thanks to everyone. I am now confident that the pinion angle is right.