Pinion angle--revisited. With Caltracs thrown into the mix.

I have determined that I have some bind on my driveshaft. Upon re-reading how to measure pinion angle, I am pretty sure I set it up incorrectly the last time.

On top of that, the terminology and + or - numbers can be confusing.

On top of all of THAT, I have caltracs.

I talked to my rearend/driveline guy and he recommended -2 degrees pinion angle for my car.

I should have asked him, but didn't think of it at the time.

Should that number INCLUDE the angle change when I preload the Caltracs?

Or is this just the "at rest" angle, and nevermind the changes the Caltracs put into the mix?

Or, more likely, will preloading the Caltracs not make enough difference anyway, so just ignore it?

 

And the current instructions don't even measure the angle of the transmission. Shouldn't that be taken into account, as well?

--http://www.quickperformance.com/Pinion-Angle-Measurement_ep_45.html

 

Nobody?

I figured someone around here has messed with this situation at some point.

 

Apparently a common question. Google search led to many situations where guys just called Calvert and got good responses.

--http://classracer.com/classforum/showthread.php?t=20026

 

Scott,

With CalTrac's the pinion won't rotate like it would with slappers or stock springs. You should offset the neg angle of the trans by making the angle on the diff pos with 3° being the max amount of "misalignment" between the two. The bud that welded my spring perches did them at -6° (he's "old school") and my trans is -4° for a total of -10°. Rather than cut the perches off and reweld them, I ended up buying a pair of 8° wedges from an off-road joint to get the pinion angle up to +2° for a total of 2°. No vibration on the drivetrain, but I still have some engine vibration I'm dealing with. Some say it's the poly mounts, some say flexplate...

 

I just found some 4 degree shims, and already tried 2 degrees. 2 was better than none, so hopefully the 4 will fix me up.

If this beautiful weather holds out til tomorrow, I will get under there, measure a couple things, and give them a try.

Also found a good suggestion on the internet about measuring the harmonic balancer face or crankshaft pulley face to get the angle of the transmission tailshaft. I think that is where I messed up last time, I could not find a good flat place to measure the transmission tailshaft angle.

 

The starter is also a good point of reference for trans angle.

 

Good point!

When I did it last time, I put it all over the transmission and couldn't a good flat reading. Never even thought about putting it on various flat spots on the engine until I read that on another website.

 

Am I missing something? Isn't this a street car? Why mess with the factory pinion angle in the first place? If you're not racing it every weekend, what are you hoping to achieve by altering the pinion angle? The CalTracs aren't going to hurt your pinion angle, they're going to control it better when you do get on the gas. My car consistently launches like my avatar on the left, and other than having a 9" swapped in, and home made CalTracs, it's still got the factory pinion angle. U-joints wear normally, no vibration at well over 100 mph, and hooks consistently.

If you're not wearing u-joints out regularly with the stock setup, or breaking mounts, what is the logic in constantly messing with it? Ford Engineers spent a lot of time developing the stock configuration for a reason, and unless you're re-purposing the car, as in drag racing, autocrossing, etc... I'm guessing if you take it back to factory, you're driveshaft binding issue will magically cure itself...and I'm also guessing you won't notice one bit of difference (other than that vibration being gone).

I've been messing with cars for a lot of years...racing since I got my license at 16, and been around tracks literally my whole life. There are a couple of things I've managed to pick up on along the way...the old adage "if it ain't broke, don't fix it" is about as true a statement as you're going to hear. Another thing I've noticed, particularly with racers (AND my Dad) is that there are always guys that just can't leave well enough alone. While attempting to sort out another of my Dad's fixes one weekend at the track, he asked how I thought we could solve the issue...I told him the best thing we could do to keep his car running smoothly would be to weld the hood shut!

Sometimes it's that simple...

 

On a factory car I was always lead to believe that the plane of the trans angle and plane of the pinion angle were to be parallel. So if the trans had a 3 degree down angle from horizontal, then the pinion should have a 3 degree up angle from horizontal.

 

In general they should be parallel at fullest load, and slightly not parallel at rest. Which is why the effect of the cal-tracs on the axle wrap is so important. I mean I'm sorry again my experience isn't with cars per se but a driveshaft is a driveshaft, and the drive should almost always be 1 or 2 degrees off from the driven. There are times this isn't true, but those times are definitely not in a car.

 

What he said.

 

I don't think scooper is going to reply to you guys.

His engine is not in the stock configuration anymore, putting his rear axle in the stock location would probably be pretty stupid.

 

Naw, I just like to screw with stuff, especially when it is working right, I like to screw it up and make it hum like a helicopter and rattle my bolts loose!

Honestly, not sure what is wrong with it. But here is my theory...

1) I dualled out the exhaust with sidepipes. No problem.

2) I put long tubes on, couldn't fit the sidepipes on them, and put glaspaks under the back seat. Started to get a low drone.

3) put on caltracs and those mufflers no longer fit as they exited in front of the rear wheels. Went and put flowmaster super44s dumping at the axle, and ended up with a HORRIBLE drone. At that point I started to mess with the pinion angle.

4) I put in a two degree shim and messed with all kinds of H pipes and such trying to get rid of the drone. It never went away.

5) driveshaft balanced, inspected rear wheel bearings, and re-evaluated engine balance and u-joint nut torques, and u-joints, etc. For a couple of years. Learned to live with the drone.

6) cut out the suspension, and dropped in a R&C power rack and pinion Mustang II setup. I am pretty sure the engine came up about an inch or two. Didn't measure, but I got rid of my original air filter and went with a low profile cool air setup just in case the hood wouldn't close when I put it back on.

7) Get engine in, back on the street a year later, and new X-pipe exhaust setup. And now it is droning, but not just drone sound, but I can feel it pulling down on the engine power as the sound increases, basically the engine surges and more so when I really stomp on it. Slap it in neutral while still moving, and all I hear is nice, smooth exhaust and engine, no drone. Back into gear while moving, and DRONE.

8) so now I KNOW it is the pinion angle. So I pull out the shims and now it is even worse.

Today I bought 4 degree shims and also read up on how to better measure the pinion angles, and I will do it correctly. I am pretty sure that I have lost the exhaust drone now, and now I need to fix the pinion angle drone that I added on accident.

Whew! Long thread, and my wife has been trying to carry on a conversation while I wrote it until she said "never mind" and went outside.

So let me go make up with her so I don't get the cold shoulder all night.

 

By the way, that all happened over the past 10 years.