svt

Can I get some fresh comments on this:

I'm putting in a LS1/T56 into a 1969 Camaro that originally had a 350/Th350.

Unfortunately I didnt measure the stock engine angle in the car but I did make sure to put the transmission output shaft at the same height as the old TH350 which seemed like the engine had to be pointing down about 2-4deg.

I have the LS1/T56 sitting 2-3deg downward from front of the car to back. The diff is 0deg, totally level. And the driveshaft is just about on the same angle as the LS1/T56 2-3 deg downward from front to back. Most technical documents say to put engine and diff at 0deg and the driveshaft at 2-3deg or adjust proportionally, ie if the engine is down 2deg front to back then the diff should be 2deg up from back to front.

But for the life of me, it seems like the stock motor had to be pointing down 2-4deg.

So, is my setup ok because thats what the factory had it set at or am I wrong in thinking the factory setup was that way, and if so, does anyone know what the fatctory setup was? i just don't see how I can set the LS1/T56 at 0deg and even if I did than the driveshaft seems like it would be in the 4+deg range unless of course I lowered the LS1/T56 but that would be impossible with the frame.

I'm using S&P motor mounts and a custom tranny mount, but I put the tailshaft at the same height relative to the frame as the old tranny.


Thanks,
Marc

Oscar Will

Driveline Working Angles Measurement (One-Piece)
Tools Required
J 23498-A Driveshaft Inclinometer





Driveline working angle does not refer to the angle of any one shaft, but to the angle that is formed by the intersection of 2 shafts. This intersection may be formed by a propeller shaft to a pinion shaft, or a propeller shaft to another propeller shaft, etc.

In a one-piece propeller shaft system, the angle formed by the propeller shaft and the transmission output shaft form the front working angle (1). The angle formed by the propeller shaft and the drive axle pinion form the rear working angle (2).

Raise and support the vehicle; ensure that the drive axle is supported at ride height - vehicle body supported by suspension components - with the wheels free to rotate. Refer to Lifting and Jacking the Vehicle in General Information.
Place the transmission in NEUTRAL.
Ensure that the vehicle fuel tank is full of fuel or that the equivalent amount of weight is added to the rear of the vehicle to simulate a full tank of fuel. The weight of 3.8 liters (1 gallon) of gasoline is approximately 2.8 kg (6.2 lb).
Verify that the U-joint bearing caps are free of corrosion or foreign material in order to ensure accurate readings of the driveline angles. Remove any snap rings that may interfere with the correct placement of the J 23498-A . Reinstall the snap rings after you take the measurements.



Position the J 23498-A onto the propeller shaft front bearing cap so that the J 23498-A is parallel to the shaft.
Ensure that the propeller shaft bearing caps are straight up and down in order to obtain an accurate measurement.
Center the bubble in the sight glass.
Record the angle measurement.
Rotate the propeller shaft 90 degrees; ensure that the transmission output shaft yoke bearing caps are straight up and down in order to obtain an accurate measurement.
Position the J 23498-A onto the transmission output shaft yoke bearing cap so that the J 23498-A is parallel to the propeller shaft.
Center the bubble in the sight glass.
Record the angle measurement.
Subtract the smaller angle reading from the larger angle reading in order to obtain the front U-joint working angle.
Position the J 23498-A onto the propeller shaft rear bearing cap so that the J 23498-A is parallel to the shaft.
Ensure that the propeller shaft bearing caps are straight up and down in order to obtain an accurate measurement.
Center the bubble in the sight glass.
Record the angle measurement.
Rotate the propeller shaft 90 degrees; ensure that the drive axle pinion flange bearing caps are straight up and down in order to obtain an accurate measurement.
Position the J 23498-A onto the drive axle pinion flange bearing cap so that the J 23498-A is parallel to the propeller shaft.
Center the bubble in the sight glass.
Record the angle measurement.
Subtract the smaller angle reading from the larger angle reading in order to obtain the rear U-joint working angle.
Compare the front and rear working angles. The angles should be equal to each other within ½ degree to provide effective cancellation of the U-joints.
If the difference between the front and rear working angles exceeds ½ degree, the angles require adjustment. Refer to Driveline Working Angles Adjustment .
If the working angles are equal to zero, the angles require adjustment. 0 degree working angles will cause premature U-joint wear due to lack of rotation of the U-joint bearings. Refer to Driveline Working Angles Adjustment .
If the working angles exceed 4 degrees, the angles require adjustment. Refer to Driveline Working Angles Adjustment .

'JustDreamin'

Hey Boss...

I'm gonna take a stab at this one. I'm not an expert, however, so anybody else with more experience please feel free to jump in.

First, some theory (for review if nothing else). If universal joints are to work properly (ie uniform output velocity) the input (that'd be the transmission) should match up with the output (that'd be the rear-end), in both longitudinal axis (both up and down AND side to side). If they're not installed in that manner (both input and output shafts parallel) they will create non-uniform velocity (the shaft will try and speed up and slow down as it rotates through 360 at a given speed). That has the effect of causing vibrations, and if it is severe enough can hammer things into submission. Case in point, I worked on a UD cabover diesel that was on its 8th Allison 5speed auto (at 37,000 miles) because the pinion angle was 10 degrees off. Driveshaft angle isn't really all that important, as long as you're not asking the universal joints to flex too far (over about 5 to 7 degrees). Ideally, a straight shot is best, however.

Alright, so you and I both know that ultimately the engine and transmission angle should match the rear end angle, and the driveshaft should fill the space in between. Since the engine and transmission aren't all thateasy to move, I'd suggest that if you have to change any angles, change it with angle shims where the rearend mounts to the leaf springs (and I'd suggest new U-bolts if / when you do this).

But, the question is, DO YOU NEED TO FIX IT? Maybe, maybe not. Reason is, you've got the factory leaf spring rear suspension, right? Well, those have some amount of "wrap" to them, so under load the rearend may very well rotate around to the correct angle. And if you adjust it so that its correct while just sitting there, it may be several degrees off under power (which is really the important scenario). I'd say that 2-3 degrees difference is probably close to what you'll need to compensate for the wrap factor, and you probably can leave it alone. I wouldn't stress over it greatly, but I would look for additional opinions. 1 opinion is either foolishness or plaguarism. Many opinions is research.

If you had a ladder bar or 4 link or torque arm type rear end, I'd say set it as close as you can to the "correct" angle and run it. But putting springs in there causes some question in my mind.

'Dreamin'

svt

Oscar, thanks for posting that , I have read that and it is one of the techincal documents I was referring to and why I posted this topic becasue it doesn't answer my questions about why a stock 69 camaro does not fit these specs.

JustDreamin you are much more on target for what I was looking for. I believe you understood what I was asking. Yes I do have leaf springs and one of my questions is did GM in fact go against their own published theory above and did not set the angles by strict theory and the reason being for what you posted, its not neccesary with leaf springs to be exact. I'm hoping you are correct and I will run it this way first and see how bad the vibration is if there is any.

So what I have is a motor/tranny sitting downward 2-3 deg which sets the driveshaft to engine/tranny at <1deg, the diff is about 0deg which sets the driveline to diff at about 2-4deg.

Thanks

Oscar Will

Driveline angles are almost always a compromise.....especially in a leaf spring car, you are absolutely correct. My "four bar" car is probably as close as you'll get to a "no variation" set-up but then not every car is a link or bar car. I think you are going to be ok, you understand the whole mess and that's what is important...to many guys go off half cocked and wind up with shakes, shudders and vibrations after the fact.

defiftyae

I have a question like svt's but for some reason i cant understand the answer. What i'm doing is installing an 5.3ls1 with a 4l60e in a chevy luv with an s10 rear and before I make the motor and tranny mounts I wanted to ask about that angle he was asking about. from what I read I understand that the tranny and rearend pretty much need to be in a straight line side to side and front to back can have 4 degrees of angle in the shaft but the tranny and rearend have to have the same angle? this is what I think. I probably sound like an idiot but can somebody draw me a picture or something. Thanks again I need a little help.

Stu Cool

iTrader: (13)

Here is some additional info, with pictures, probably more than you'll ever want to know:

http://www.carcraft.com/howto/91758/

http://www.roddingroundtable.com/tec...driveline.html

http://www.4crawler.com/4x4/CheapTri...line-101.shtml

'JustDreamin'

Those are pretty good links.

'Dreamin'

defiftyae

thanks for the info it will really help!!

81LS1Camaro

iTrader: (1)

Wow, alot of good info, I thought I already knew how to measure the angles, no wonder my other camaro has a vibration.