Drive line angle

[Falcon67]

I make sure they are not parallel.  If they are each about 2 degrees out from each other, it's good.  I've done a lot of reading and run a lot of drivelines - drive line / pinion angle never did anything for traction or 60', unless your pinion angle approaches 90 degrees in either direction.  180 is worse, seen that also.

[The Real McCoy]

Tremec has a drive line angle finder for your smart phone.  It also has some calculators for MPH, RPM, and Tire Sizes.  They all seem to work pretty slick.

http://www.tremec.com/menu/tremec-toolbox-app/

[Bolted to Floor]

Tremec has a drive line angle finder for your smart phone.  It also has some calculators for MPH, RPM, and Tire Sizes.  They all seem to work pretty slick.

http://www.tremec.com/menu/tremec-toolbox-app/

I will take a look at that. Thanks

[My427stang]

You can also just use the compass on your IPhone, swipe left to the angle feature

[Pentroof]

And for easiest measurement of the tranny output, I put the edge of the phone across the tops of the oil pan bolts.
For the diff measurement, I put the phone vertically against the pinion yoke bolts and calculate a 90 degree offset.
This is just for simplicity and they are always spot on. Trying to measure from the face of the joint caps or something just gets squirrelly.
And make sure the weight is on the wheels when you measure! A 4 post lift is handy for this.

[Bolted to Floor]

Thanks for the tips guys. I didn't realize it was that easy to measure angles with an IPhone. I used the TREMEC app for the calculator and got a passing score 3 out of 4 tries. I will get the car up in the air again next week and take the readings were Pentroof suggested cause it did seem “iffy” at times if I was actually flat across the joint caps.

[My427stang]

What did you get for all three angles with weight on the wheels?

[Bolted to Floor]

Ross, the transmission was 6 degree down, driveshaft 5 degrees down and pinion is 7 degrees down.

[My427stang]

Ross, the transmission was 6 degree down, driveshaft 5 degrees down and pinion is 7 degrees down.

So given these numbers, I don't think you are bad at all with static numbers, but under any acceleration, as I said in the other post, without some sort of traction bar, you are likely over-centering a little as the pinion comes up.  My guess is with even the slightest acceleration you are likely tranny 6, driveshaft under 5, and 5 or even less on the pinion.  Numbers don't look bad but that pinion will always be trying to unload as load changes and on hard acceleration could be rising a lot more

This isn't the greatest video, but take a look at how much pinion angle can move, just on the street

https://www.youtube.com/watch?v=54_6GaYJvWI

If you are confident in your numbers, my choice would likely be to leave it as is and add an cheap under-rider bar.  However, if I was tweaking it, I'd likely add a little shim under the rear tranny mount, to the point where I didn't have to cut, just to correct back a little more.  Not sure if you could get to tranny 5, driveshaft 6, and leave the pinion alone but control it with the bars, that likely would work out pretty nice there without cutting the floor  (assuming you have good fan clearance).

[Bolted to Floor]

Thanks Ross. I will see what I can fit in for a shim at the transmission. I did measure from the fan to the radiator today, there was 1-1/2” at the top and about 1” at the bottom.

[My427stang]

That fan spacing makes perfect sense.  I used just under 3/4 of an inch of spacer in my own, but it really depends on cross member design.  Needless you say you can't tuck it all the way up without cutting the brace, also watch for the vent in the front of the tranny, right under the radio, but if you can get closer it'll only help.  Good setup work.

FYI - If you decide not to go with underrider bars, you'll likely have to drive the pinion a little lower.  I recommend against it though, it's a catch 22 if you don't stop wrap up.  No bars you need more angle, more angle means more vibration at cruise.  The ones below I have on mine are cheapies, I think I paid 69.99, but they sure do the trick, and have done so since 2005.  Same as the link below

https://www.summitracing.com/parts/sdk-tm-1069-p?seid=srese2&cm_mmc=pla-msn-_-shopping-_-srese2-_-scott-drake&utm_source=bing&utm_medium=cpc&utm_campaign=Bing+Shopping+Ads&utm_term=1100100889323&utm_content=All+Products

Of course there are fancier methods if you plan to race.  Caltrac springs have a strong front single "leaf" that doesn't bend much and the rear of the spring does the work, combined with Caltrac bars, it'll hook like nobody's business, but 100 bucks versus 800 or so, depends on your intended use.

[Bolted to Floor]

Well....I noticed after the trip the tire was rubbing more when the car was empty. When I got to looking, I found a new twist, I guess bend is a better word.





The new Grab a trak 4 1/2 leaf standard eye springs are on order along with 1/2" lowering blocks and a 2 degree shim. How the car sits, the pinion angle, and if I can get a shim under the transmission mount will dictate what I use. I will also try to use one or the other to center the rear end in the car.

Some sort of traction device is on hold till I can get the new stuff installed.