Drive line angle

[Ducs]

I am mocking up a LS1/T56 drive train in a G body frame and I am wondering about drive line angle "left/right". I am going for 3 degrees drive train tilt, but I am not sure if I am correct with setting the T56 output shaft right on the centerline of the frame. Rear end's pinion is definitely not on the frame centerline. Are there any guide lines to follow ?

[bryant]

you want the motor/transmission center line parallel to the center line of the car if you were looking at it from above or below. It can be offset from the center line of the pinion which is also going to be parallel. The drive shaft u-joints will take care of any offset.

[Ducs]

I've set the motor/transmission center line exactly at frame center line when looking at it from above or below. Center line of the pinion would be parallel to the frame center line, but is definitely offset to the passenger side.

[andrewb70]

I've set the motor/transmission center line exactly at frame center line when looking at it from above or below. Center line of the pinion would be parallel to the frame center line, but is definitely offset to the passenger side.

Offset is OK as long at the engine/trans line is parallel to the pinion gear. You can figure out the resulting u-joint angle (looking from the top or bottom) by taking some measurements and applying some geometry.

Or you can do like I did on my Cougar and use a driveshaft with CV joints front and rear and not worry about any of it.

Andrew

[TheJDMan]

Stock GM rear ends were installed from the factory with a 1/2" pinion off set in the F Bodies not certain about the G body. Personally, I would install the engine/trans with zero off set side to side and a 3deg angle down front to rear. When I installed my 9" I had the option of welding the rear end mounts with the 1/2" offset or zero offset, I went zero offset on the rear.

As Andrew said the CV driveshaft may be required in the end.

[q67]

Hi Andrew, I have been chasing a Drive line vibe for a while and I am considering a D/S with CV joints front and rear, do you have any pics of yours?

[Ducs]

[Knowing that pinion on my rear end is factory offset while the drive train is set at zero offset with respect to the frame center line, do you know what acceptable angles can drive shafts u joints work at ?

[SSLance]

I'm pretty sure my balancer is about a half inch to the pass side from dead center of the frame and my trans mount is about a quarter inch to the pass side from dead center (it's been a long time since I measured and mocked it all up). I spent way more time getting my up and down u-joint angles in line, the side to side angles are so slight they have very little effect on vibration.

[garvir]

my monte carlo had -6 degrees down at the trans, -2 degree down at pinion, i had a vibe, lifted the trans +4 degrees, to -2 degrees, this in turn brought the pinion a up to +2 degrees, they were both off 2 degrees buy parallel. no vibe now... this is the way bob bolles from circle track mag explains it, parellel and opposite. you probably could get away with 1 degree differance because of the car moving up and down when you are moving, so the bearing would move.

i was lucky able to put my angle finder on the ujoint caps, gave me a true reading. the trans pan is not a true reading, they are off 2 or 3 degrees. the same with pinion, no where to get a true reading except the ujoint caps. make sure the u joint is straight up and down, put you angel meter cross car to check vertical.

[68byrd]

If you have a smartphone or iPod, the free tremec app is really good for drive line angles.

[MOREHORSEPOWER]

If you have a smartphone or iPod, the free tremec app is really good for drive line angles.

And a lot of other things ! Like making sure the block is level !!