Lets beat a dead horse

[h3towel]

Good morning all. Time for another episode of stupid questions with your host H3Towel. I just started my roadster this past weekend for the first time. Absolutely amazing feeling. As I move forward to being able to drive it around my court, I'm trying to figure out the whole drive shaft angle thing. I have the tremec app, but I am unable to get acceptable angles. Does the car need to be under it's own weight, or with the rear suspension fully extended? Do I need to set it to the proper ride height first? If so, what is the proper ride height? I have a tremec TKO 600 and 3 link suspension. Any help is always greatly appreciated.
On a side note, I purchased a battery shut off switch as an extra level of theft deterrence. I want to keep the battery connected, so I was thinking about putting the switch on one of the ignition wires. Any one have any thoughts?

Cheers

[ChasNMe]

this is what a lot of people go by

Pinion Angle (Driveline) Setup Procedure . . . by Karlos
https://thefactoryfiveforum.com/showthread.php?22594-Driveline-Setup-(aka-Pinion-Angle)

[boat737]

And yes, the car needs to be at ride height to measure and set the pinion angle. You can set this at any stage in the build, but as you progress and finish the build (adding weight, body, paint, carpet, seats, stuff) you will have to re set the ride height. That is the way to set up your driveshaft pinion angle. After a few hundred miles on the car it might settle a bit, so you should re-check and re-set the ride height again. Most go with 4" front, 4 1/2" rear, measured from the bottom of the 4" frame tubes. I'm a bit less at 3 7/8" front, 4 1/4" rear.

[JohnK]

ChasNMe - thanks for posting that link. I had not seen that before and was definitely confused by the terminology and process for setting pinion angle, so that is extremely helpful.

boat737 - For a car with IRS, where the engine/trans and IRS do not move with respect to each other with suspension movement, I'm assuming that setting ride height doesn't matter?

[karlos]

The link posted above is a few years old. Info's still good, but perhaps too heavy on the theory for a lot of people. For a simple description of what specifically needs to be done, try this:

Start with all the major components installed: engine, transmission, driveshaft, differential. Bolt the transmission mount to the chassis but don’t attach it (yet) to the transmission. Place a jack under the transmission and lift the rear until there’s approximately a ¾” gap between the transmission and the transmission mount. Most installs (at least those using TKOs) seem to end up in the vicinity of a ¾” gap, so this represents a good initial starting point.

With an initial gap of ¾”, use an angle finder to measure the angles at the transmission, the driveshaft, and the differential. Also note whether each of those three components is sloped upwards or downwards as measured from front to rear. Put the measurements in your favorite software tool to check the angles. If all good, make a ¾” shim and install it between the transmission and the transmission mount. Bolt everything together and you’re done. If the angles aren’t in spec then use the jack raise or lower the transmission in small increments (about 1/8” will have a substantial effect on the angles), re-record the angles, and re-enter the values into the software. Keep making small changes up or down until all angles come back good. Once that happens, make a shim with the same thickness as the measured gap, bolt it up, done.

All that leaves is figuring out what software to use. The online calculator from Spicer works well enough, but it doesn’t tell you directly whether all three angles are within spec. The Tremec phone app is better, but it has the unfortunate tendency of changing the angle you’re trying to measure, making accuracy/repeatability a problem. If you’re comfortable using MS Excel I have a worksheet that simplifies the whole process. Just enter your values and confirm the relevant cells turn green.

More than happy to share a copy of the worksheet with anyone that would like it. PM me with your email address and I’ll send a copy.

And yes, ride height can be ignored for an IRS car.


-Karl

[GoDadGo]

This Short Video helped me and many others understand the Drive Shaft Angle & U-Joint Phasing Issue.

https://youtu.be/Idk3BVDVHq4

The good news is the 3-Link, in my opinion, is the easiest by far to set up.

[Blue Viking]

Great info. Right now in the process of fitting the T56 and the driveshaft. Just ordered an electronic angle finder, should make the fitting a breeze.

[BEAR-AvHistory]

And yes, the car needs to be at ride height to measure and set the pinion angle. You can set this at any stage in the build, but as you progress and finish the build (adding weight, body, paint, carpet, seats, stuff) you will have to re set the ride height. That is the way to set up your driveshaft pinion angle. After a few hundred miles on the car it might settle a bit, so you should re-check and re-set the ride height again. Most go with 4" front, 4 1/2" rear, measured from the bottom of the 4" frame tubes. I'm a bit less at 3 7/8" front, 4 1/4" rear.

I moved up to 4" in front. Was scraping on shopping center speed bumps. Some seem higher than they used to be.

[boat737]

...should make the fitting a breeze.

Oh, how many times have I said that.

[rich grsc]

Great info. Right now in the process of fitting the T56 and the driveshaft. Just ordered an electronic angle finder, should make the fitting a breeze.
Free angle app for your phone.

129376

[CraigS]

I used fender washers to make my initial attempts. Stack them up till you have good numbers and then measure if you want to make a solid spacer. Another option is some 1/8x2 inch flat stock aluminum or steel to make a spacer that encompasses both bolts.

[Blue Viking]

Oh, how many times have I said that.

Haha, hope i didn't jinx it now....

[Blue Viking]

Free angle app for your phone.

129376

Yes i know, but i like shiny new tools.

[rich grsc]

Yes i know, but i like shiny new tools.

You have extra $$$$, send me some!!! :p

[phileas_fogg]

I was never able to get repeatable measurements from my phone. The poptart size & rounded edges of today’s cell phones prevented me from getting the phone flush with the measurement surfaces. The right phone will probably work, but for me the angle finder did the trick.


John

[Al_C]

On a side note, I purchased a battery shut off switch as an extra level of theft deterrence. I want to keep the battery connected, so I was thinking about putting the switch on one of the ignition wires. Any one have any thoughts?

Cheers

It doesn't look like you got a lot of info on the cut-off switch. If you plan to race, you would want that to be a complete battery cut off and have the switch where someone outside the car can reach it. (Don't quote me; this is my understanding)
If you are running a coyote, you will want a hot-at-all-time connection, but you can achieve that with the cut off.
If you ONLY want theft deterrence, your method will definitely work, but you could do a lot more with the switch than you noted here.

In my case, I use the cut off as both theft deterrence and cutting power for safety reasons. The hot side of the switch has a connection to the PCM so it is always powered up, but everything else in the car is disconnected. All I'm suggesting is that you could take greater advantage of your switch.

[karlos]

I was never able to get repeatable measurements from my phone. The poptart size & rounded edges of today’s cell phones prevented me from getting the phone flush with the measurement surfaces. The right phone will probably work, but for me the angle finder did the trick.


John


Yep, that's the problem I was referring to with the Tremec app. And to make it even worse, the app requires that you tap on the screen to lock in the angle. The act of tapping on the screen also causes the displayed angle to change.

The angle finder on the phone is free, and I'd say it's worth every penny ;)