Getting the angle of the dangle

[The WidowMaker]

the problem i have with 3* down, is 3* compared to what? where on the frame do you measure? rocker? door sill? what happens when you put it on jack stands and its not supported by the tires and your rake changes? what happens if you change the stance later?

start with parallel, and if that works and youre working angles are pretty low, leave it. if they are not, you may need to point the pinion down to get your working angles in an acceptable range. although its different than what youre commonly told, most dont run the ride heights that we do.

heres a site to check out. you can download a free trial and input all of your information, and it will tell you where to move what.

http://www.vibratesoftware.com/html_...ons.htm#1Piece

Tim

[ProdigyCustoms]

4 degrees of engine trans ngle is fine, and at ride height, If you point the pinion at the transmission output and go a 1/2 degree down, your golden.

[GregWeld]

Originally Posted by The WidowMaker

the problem i have with 3* down, is 3* compared to what? where on the frame do you measure? rocker? door sill? what happens when you put it on jack stands and its not supported by the tires and your rake changes? what happens if you change the stance later?

start with parallel, and if that works and youre working angles are pretty low, leave it. if they are not, you may need to point the pinion down to get your working angles in an acceptable range. although its different than what youre commonly told, most dont run the ride heights that we do.

heres a site to check out. you can download a free trial and input all of your information, and it will tell you where to move what.

http://www.vibratesoftware.com/html_...ons.htm#1Piece

Tim

Tim ---

RELATIVE TO THE CHASSIS BEING LEVEL - Suspension loaded. These settings we're talking about are pinion angle relative to the Engine. So if you start with a level chassis - set the motor down relative to that - and the pinion angle relative to the setting of the motor.

Now --- from there.... there are different opinions and settings for different suspensions i.e., 4 link vs leaf springs etc. Leaf springs will allow the nose of the pinion to "crawl" upwards... so in days of yor - a pinion might have been set down 4* if you were drag racing etc - and as you applied power it would rise to be say -- down 2* or maybe even 0*...

The whole thing is about angle cancelation - and having an angle difference so that the needle bearings in the caps spin. Too straight and they won't spin and you'll wear 'em out in short order -- AND -- the u joint needs to "wobble" (that may be the wrong use of the word) relative to each other.

I hope that I explained this correct -- Frank -- Jump in there if I didn't. I also agree with Frank -- motor down 4* and pinion down 1/2* in these 4 link rear ends... they don't crawl much. My Jim Meyer chassis - and the Art Morrison Chassis I'm working on right now - set the motor down 3* (observed).

There are lots of 'old skool' trick and things that were done and people have kind of stuck with them. For instance - if I'm tightening the u bolts (billet caps in my case) I watch the split washer just go flat - and give it another 1/4 turn. Never had one come loose yet - and I haven't worn out any U joints either. It's just the way I've always done it because that's the way I was taught...

[DRJDVM's '69]

Thanks

How critical is the centerline?

My engine is not centered....but neither is my rear end pinion... the tube on the driver side is shorter, so the actual pinion yoke is shifted toward the pass side...just like the motor. Now that I have it all in there, and have shifter it back and forth alittle to get the tires exactly where I want them (probably not the exact same spot as when I mocked it up and measured), it looks like I could have shifted the pinion yoke maybe another 1/4-1/3 inch to the pass side to get everything dead center in the tunnel.

I've read up on it alot and it doesnt seem that critical....alot of Mopar guys are running centered pinions (axle length same on each side), with the standard offset motor and dont have issues. Basically they find great deals on used centered pinion yoke rearends, and just use them without changing anything...maybe beating in the tunnel a tad

So if the centerline is not dead on, is that a problem?

[GregWeld]

Ned --

I said in my first post - that MOPAR built cars with the engine skewered to one side...

Just get your rear end "centered up" with the engine centerline. Centerline is a RELATIVE measurement - i.e., relative to each other...

[GregWeld]

Oh -- and by the way -- the reason there's a u joint on both ends of the driveline -- is because they're never really static - the old leaf springs allowed the rearend to shift side to side in a corner (no panhard bar back in the day) as the leafs rolled over - and it never stops going up and down!!

[The WidowMaker]

RELATIVE TO THE CHASSIS BEING LEVEL - Suspension loaded. These settings we're talking about are pinion angle relative to the Engine. So if you start with a level chassis - set the motor down relative to that - and the pinion angle relative to the setting of the motor.

all im saying is where do you measure? i could pick 10 different spots on the frame, and each would come up different. obviously i pick the same spot every time for my own sanity, but when numbers are thrown around on the internet its never given what the heck is being measured and compared

I also agree with Frank -- motor down 4* and pinion down 1/2* in these 4 link rear ends... they don't crawl much. My Jim Meyer chassis - and the Art Morrison Chassis I'm working on right now - set the motor down 3*

which way is the pinion when you say 1/2* down? 1/2* to the chassis or the 4* of the motor? if youre talking about a 4* tailshaft and a 3.5* pinion, it usually works. in my situation, the pinion is sitting higher than the tailshaft, therefore the common \ _ \ setup yielded working angles that were approaching 4*. will it cause an isssue? probably not. but, when starting with a clean slate its best to get them right at 1* but not under. the less common \ _ / is what i ended up going with. i still have working angles that cancel each other in order to minimize harmonics, and i still left .5* for pinion wrap.

How critical is the centerline?

you want your working angles as close to 1* as possible (without going under since they will stop rotating as greg stated), and you want both angles to be within .5* of each other.

if you set up your tailshaft and pinion in a straight line and have 0* working angles in plan view, youre needles will still rotate since you have enough of an angle in side view. but if your wa's are huge in plan view, it doesnt matter how much work youve done to keep them minimized in side view, you might end up with a high speed vibration.

i know im over thinking the crap out of this, but i didnt want to end up being one of those "high speed vibration, need help" threads once this thing is finally on the road. what frank and greg said will usually work, but i know youve got yourself a pretty low ride and its worth really checking into the working angles.

Tim

[Vegas69]

I'd start with 2-3 degrees if your tunnel clearance will allow it.

[dtedler]

Hey Ned - The cross member that I am sending you will have the pinion angle set a 2 1/2 degrees down using the stock mounting location. With your suspension being channeled up another 1 1/2" in the chassis this will increase the angle by.......let me play with the CAD and I'll tell you exactly. More to come.

Tony Edler
Hurst Drive Line Conversions