Driveline/Drive Shaft Angles Tolerance

[NewZed]

You only rotate to get the axes parallel.  Not to line up.  That's the whole key to the concept.  The axes have to be parallel.  The only reason to move the engine over would be if the angle of the joint is too great.  Maybe they measured the angle and decided it was too much.  You'd need to see their numbers to know for sure.  Did they show any numbers?  (You could also post the link if you wanted to).

 

https://www.moderndriveline.com/a-little-information-about-u-joints/

 

 

 

 

[363z]

this diagram shows a height parallel alignment where I am talking left to right

[NewZed]

It's a 360 degree thing.  Left right up down 45 45...full circle.  But if you get left and right and up and down right, they 're all right.

[363z]

ok I got it thanks. Sorry I thought it had to be straight and the sbf to r230 is just off more than I thought it would be ok.

[NewZed]

It's not really obvious.  Everyone has to ponder it to make sense of it.  I'd just find a procedure on a web site that you trust and follow it.  People have made their own special tools with laser beams and stuff to get it done right.  No Sea Bass though.

 

Here's that Laine family link.  I haven't read through it.

 

https://www.lainefamily.com/240Z_V8_Conversion.htm

[363z]

I've spoken directly to them and their mount is 3/4 off center so I'm going with that

[NewZed]

7 minutes ago, 363z said:

I've spoken directly to them and their mount is 3/4 off center so I'm going with that

 

You still have to do up and down.

 

Good luck.  If you have vibrations you'll know where to start over at.

 

 

[grannyknot]

1 hour ago, 363z said:

I've spoken directly to them and their mount is 3/4 off center so I'm going with that

 Their mount was actually designed by Ron Tyler and it's usually called the RT mount, the Laine's just produce them now.

The mount is 3/4" off center because the R160, R180, R200 diffs are mounted 3/4" off center, I don't know if your R230 diff is or not, hopefully it is or that will really screw things up.  All you can really do in a case like that is move the sbf over 3/4" so that the trans and the diff are basically inline then start tilting the engine/trans and the diff until they are pointing parallel to each other.

I've done this many times and a digital inclinometer makes the job a lot easier.

 

[NewZed]

No offense intended to anyone but you do not have to move the engine unless the angle is too big.  You just have to think in terms of two planes.  I would guess that the side to side angles are already correct if the engine mounts are factory stock and the diff mount has the halfshafts pointed at the wheel centers.  If the crankshaft and the pinion shaft are parallel with the cars body then you don't need to worry about alignment but you do need to make sure the angle is small enough.  that's the critical one I think the size of the angle. Move it if the angle is too big but don't move it because it's not pointing directly at the diff.

 

https://vibralign.com/shaft-alignment/understanding-offset-shaft-alignment/

 

"That is, the angle of the yokes on both ends of the shaft will be equal when the driven and driver are on parallel planes in the vertical and horizontal axes. 

 

https://www.markwilliams.com/driveshaft-measuring.html

 

In a perfect world the centerline of the transmission output shaft would be exactly parallel to the pinion centerline on both vertical and horizontal planes (but not “pointed” at each other).

 

 

[363z]

problem is the angle even with motor shifted is 3.9 degrees which I understand is too much or is over the 3 deg threshold you want based on driveshaft length.

[grannyknot]

3 hours ago, NewZed said:

I would guess that the side to side angles are already correct if the engine mounts are factory stock and the diff mount has the halfshafts pointed at the wheel centers.  If the crankshaft and the pinion shaft are parallel with the cars body then you don't need to worry about alignment but you do need to make sure the angle is small enough.

Why would you assume the side to side is the same as an L series engine?  The stock engine does not sit dead centered in the engine bay, it is slightly off center just like the diff. If you drop a V8 in and center it in the engine bay your angles are too much to get a vibration free  drive shaft regardless of whether the crank and pinion shaft are parallel.

The diff is limited in the amount it can be adjusted, you can make it point up a little or down a little, it can also be lowered a bit too, that's it.  All other adjustments has to be made with the engine/trans in order to decrease the angles and make them parallel.

No other engine but the L series was designed to go in that engine bay so when drop something different in there you have to compensate in many ways to make it work.

3 hours ago, 363z said:

problem is the angle even with motor shifted is 3.9 degrees which I understand is too much or is over the 3 deg threshold you want based on driveshaft length.

Okay, you have to take some photos and post them so we can see what your situation is, 3.9 is no good, you could get away with it at low speeds but the vibrations are going to be bad at certain speeds and might be dangerous depending on the road conditions.

I have tried to figure out how I could point the diff to the left or right but have never been successful so I have always had to make the engine/trans do most of the adjustment.

[NewZed]

I meant that the engine's crankshaft is most likely parallel to the body's centerline.  Like the diff's probably is.  Because they started that way.  The up and down is where things change when you do swaps.  The engine and diff can both be tilted up or down easily, and can therefore be not-quite-right.

 

Anybody who get their engine or diff mounted crooked is going to have other issues besides drive-line vibration.

[NewZed]

Just to give another perspective on what these various sites are saying about two planes...imagine that you're floating above your car and you can see the lines that run through the pinion shaft of the diff and the transmission's output shaft.  They need to be parallel.

 

Then imagine that you're laying on the ground beside the car looking through it and can see the same lines.  They need to be parallel.

 

That is one of the fundamentals of drivetrain alignment to avoid vibration.  The size of the angle is separately important to avoid damaging the u-joint.  Too little is bad and too much is bad.  But the front and back angles need to be the same, regardless.

 

That's all I'm saying.  If you can get the lines parallel and the angle within the recommended range, then there's no need to move engine or diff.  But, you have to take the angle measurements.  3/4 inch doesn't mean anything.  Only the angles do.

[363z]

right well motor is on motor plate but diff is in "stock" swap location.  Tuff to find anywhere to measure off of from "floating above the car" to make sure engine is parallel to diff. Thinking iys just going to have to be what it is and see but as someone said, as high speeds will be dangerous.  

[NewZed]

Agreed, if you can't take a measurement just eyeball it in there and hope.

[grannyknot]

9 hours ago, 363z said:

right well motor is on motor plate but diff is in "stock" swap location.  Tuff to find anywhere to measure off of from "floating above the car" to make sure engine is parallel to diff. Thinking iys just going to have to be what it is and see but as someone said, as high speeds will be dangerous.  

Hoping you get it right is a risky way to proceed, once you get it in the ball park you need to start measuring.  Even a piece of 2"x2" cut to fit snugly between the tail of the trans and mounting plate of the diff will give you visual reference and a flat surface to start measuring from with a dial or digital inclinometer .

This is just the most recent discussion on driveline angles but there are many more by searching this forum.