85ls1

I havn't seen anyone mention what the angle that there engine is at, or what there pinion angle is. We're putting a ls1 into a '85 Camaro. the angle is 4 degrees down at the rear of the engine. That's as close to level as we can get it. Is that good enough? Should the pinion angle then be 4 degrees up?

63 Split Window LS1

This just my opnion so take it for what it cost. I have been told, by custom car builders that I respect, that you need some angle on the engine because if its level with the drive shaft you will pick up some bad harmonics. From years of racing I learned you need some down angle on the rear end to get maximun bite under hard acceleration. I would leave the engine angle at 4 and put 2 degrees down angle on the third member.

jeromio

We have ALOT of discussion and info on this subject over at http://hybridz.org.

The short of it is that if you draw 2 imaginary lines, one coming directly out the trans output and another coming out the pinion, these 2 lines must be parallel. BUT, they must not be the same line. In other words, there should be 2-4 degrees or so of offset so the cupsin the U Joints turn and get continuously lubed.

What I did for my swap was use an angle finder. I put it against the flat parts of the trans output and the diff input and made sure that those 2 angles were identical. That's for the vertical position. For the horizontal alignment, I had to make sure that the motor/trans was perfectly straight relative to the frame.

For my particular car, the driveshaft ends up being slightly angled in both the horizontal and vertical, by about 4 degrees. But the trans output and the diff input are are straight relative to each other. This means that the 2 UJoints are in phase and there should be no harmful harmonics.

The take home msg here is that the angle of the of the DS relative to the pinion or trans is not really very important (as long as it is reasonable and not some extreme angle). What IS important is the trans and the diff alignment relative to each other.

Derek 357i

iTrader: (1)

So what if you are using an IRS and the way it is mounted, you have no way of ajusting the relative angle of the output yoke? I am going to do everything in my power to make these two angles equal, but things like how low you can get the engine and how high in the tranny tunnel you can get the trans will greatly affect ones ability to manipulate this relative angularity.

jeromio

You ought to be able to adjust the position of the diff: raise/lower the back or the front with shims. On the Z car, v8/trans tends to point a bit more upward than the stock L6. So the rear of the diff has to come up to get the pinion to point down a bit more. But the rear mount bar ("mustache" bar) has some washers above it that can be removed to un-shim it.

I suspect it's actually a little easier to align the Ujoints in phase with an IRS car since the diff is fixed and not moving with the suspension. In most of the old school swaps (camaro, vette, chevelle, etc.), the car had a 350 in it so the LS1 sits in almost exactly the same spot - simple. But if you were swapping into say, an MGB or something, I think it'd be tricky to position the rear axle correctly (shims betw. axle and leafs? adjustable shackles?).

LS1 IROCZ

If you get an adjustable torque arm, you can adjust the pinion to drive shaft angle all you want. more for race.. less for street.