Pinion angle question for a math idiot

**bberretta** · 10-18-2010, 09:35 PM

I'm hoping I set it up right, hopefully someone can help correct me!

Measured the output shaft and the yoke with a magnetic angle finder with a load on it.

Output shaft = -6 degrees (pointed downward)
Yoke = +5 degrees (pointed upward)

So does this mean I'm sitting at -1 degrees or am I looking at this all wrong? Hopefully the driveshaft will arrive tomorrow and I want to make sure I have everything set up correctly so I can get this thing on the road!

Thanks in advance- this is the first time I've ever done a pinion angle, so any help (and well deserved mocking) is welcomed!

**Firebirdjones** · 10-19-2010, 08:12 AM

Your output shaft on the transmission is actually pointing downward at -6*??? That's odd to say the least.

Usually you will have a positive number here (pointing upward) or at least pretty level. I like to measure them with the driveshaft out, so I can attach the angle finder directly to the output shaft, to be sure I'm directly in line with the cranshaft/outputshaft centerline.

Then I'll take a large deep well socket that fits into the yoke of the rearend housing (again driveshaft removed). And take a reading from that with the angle finder.

You take the positive number from the transmission output shaft and the negative number from the rearend yoke to get your pinion angle.

For instance, +3 at the trans, and -3 at the rearend means you would have a "0" pinion angle. If you moved the rearend down to say,,,,-5 then you would have -2 pinion angle, which is a good starting point for a street strip car. Hope that makes sense for you.

**bberretta** · 10-19-2010, 10:34 AM

I noticed when I installed the poly motor mounts that the motor sat up a bit more so it doesn't shock me at all. I do still have the driveshaft out (new PST shaft should arrive today).

Sounds like I'm in the ballpark, I need to just double check my angles to make sure they're right. I know the trans is angled down and the yoke is up, but I need to double check the numbers.

Thanks!

**Firebirdjones** · 10-19-2010, 11:40 AM

Originally Posted by bberretta

I noticed when I installed the poly motor mounts that the motor sat up a bit more so it doesn't shock me at all. I do still have the driveshaft out (new PST shaft should arrive today).

Sounds like I'm in the ballpark, I need to just double check my angles to make sure they're right. I know the trans is angled down and the yoke is up, but I need to double check the numbers.

Thanks!

Ah okay, sounds like you are the other way around then. You want your rearend yoke to point slightly downward, and the trans the opposite.

New poly mounts would explain the issue then, sounds as though you might need to shim up the tranny mount.

**bberretta** · 10-19-2010, 12:35 PM

Tried but couldn't get it high enough before it hit the tunnel. Literally had over 1/2" of shims in there and it still hadn't zeroed out.

**Firebirdjones** · 10-19-2010, 12:42 PM

Originally Posted by bberretta

Tried but couldn't get it high enough before it hit the tunnel. Literally had over 1/2" of shims in there and it still hadn't zeroed out.

WOW

Sounds like those motor mounts are really causing you an issue here.

**bberretta** · 10-19-2010, 12:46 PM

Don't say that- those were a PITA to install! Does the Trans have to angle up and rear down because the rear sits higher than the trans? I'm sitting at stock height, but this has been the most difficult part of this 9" installation. Everything else has been smooth.

**Firebirdjones** · 10-19-2010, 12:50 PM

Originally Posted by bberretta

Don't say that- those were a PITA to install! Does the Trans have to angle up and rear down because the rear sits higher than the trans? I'm sitting at stock height, but this has been the most difficult part of this 9" installation. Everything else has been smooth.

Didn't mean to spook ya. The trans should be closer to level or slightly up. You say the rear sits higher than the trans,,,,so I assume you mean the pinion angle is actually pointing up towards the floor of the car??

If so, that should be pointing at a slight downward angle towards the garage floor. Wish I were there, it would give me a better idea of what you are dealing with.

**bberretta** · 10-19-2010, 12:59 PM

The trans sits higher, so it angles down toward the ground 6*. The rear sits lower and angles up torwards the floor of the car 5*. This means they are almost at a straight line to one another.

**35th-ANV-SS** · 10-19-2010, 01:07 PM

So right now you have a pinion angle of -1 degrees. You would need to rotate your pinion down another 1 degree to get -2, what is desired.

I think...

**bberretta** · 10-19-2010, 05:52 PM

-2 for poly bushings, -1 for solids. I have the MidWest Chassis adjustable LCAs with the solid links.

**Firebirdjones** · 10-20-2010, 07:28 AM

I'd probably wait until the driveshaft comes in, and check the driveshaft angle coming down to the rearend verses the pinion yoke angle just to be sure before you call it good.

**tording** · 10-20-2010, 01:37 PM

Yes wait for the driveshaft and measure the driveshaft angle coming down to the yoke, measuring the output shaft is not going to do any good.

**bberretta** · 10-20-2010, 05:10 PM

Driveshaft was the same- -6*. Called it good and took it for a drive. No wobble so I think it's good. Might have to get back under it since I got an alignment and double check the angle since the shop moved the LCAs.

**Frozen WS6** · 10-20-2010, 08:33 PM

This is what I went off of.

http://support.spohn.net/questions/1...inion+angle%3F

http://www.wolferacecraft.com/pinionangle.aspx

**bberretta** · 10-20-2010, 08:59 PM

A couple more:

http://buickperformance.com/Pinion.htm

http://www.ssz28.com/tech/Pinionangle.html

And a vid:

[ame]http://www.youtube.com/watch?v=UAQgLbhQ0uk[/ame]

**Firebirdjones** · 10-21-2010, 07:40 AM

Originally Posted by bberretta

Driveshaft was the same- -6*. Called it good and took it for a drive. No wobble so I think it's good. Might have to get back under it since I got an alignment and double check the angle since the shop moved the LCAs.

Thats good to hear. I must have been misreading you and thought you had some really severe angles going on.

**bberretta** · 10-21-2010, 08:16 AM

Thanks for all your help. Just talking it out made it much easier to grasp. Really not sure why I made this so difficult on myself!

**35th-ANV-SS** · 10-21-2010, 09:04 AM

Originally Posted by bberretta

Thanks for all your help. Just talking it out made it much easier to grasp. Really not sure why I made this so difficult on myself!

No worries. I tend to over-analyze a lot of simple things. I think it is the engineer in me.

**JoshuaGrooms83** · 01-13-2011, 12:10 PM

SWEET! Thanks guys, really needed this info. I was so lost on the other threads. If anything, this one needs to be a stinky in the Pinion angle thread. THe other one is just too complicated for us commom folk lol.

Just did my angle. Got 2 for DS and -5 for Pinion. thats -3 right? I tryed playing with it a bit and this is the best i can get right now without messing with the top part of the TA.