Getting the angle of the dangle - Lateral-g Forums

DRJDVM's '69 · #1 04-25-2010, 11:53 PM

Lets talk angles....

So I have my mock up motor in..... T56 magnum is on its way..... got my Moser Dana 60 mocked up pretty close...

The k-frame I used has been channeled into the frame by about 1.5 inches so I'm gonna have to modify the trans crossmember since essentially eveything has been raised...motor mounts are set......axle perches on the Dana are not welded on....so basically I can tilt the engine angle, trans angle and rear end angle to whatever I want.

I figured I should probably work from front to back.....in other words, get the trans hooked up to the motor and then tilt the rear of the trans up and down until I get the angle I want/need for the motor...then modify the trans crossmember to keep it at that angle....

The intake manifold surface is parallel to the pan, so I can use that to measure the engine tilt back to front.....or I can use the crankshaft snout......

If I remember correctly, I want a "tilt down in back" angle of about 2-4 degrees on the motor....does that sound about right? Its an EFI car.....

Then get my pinion figured out for the rearend......since that will be dictated by the trans/motor angle

Since I can set any of these angles to whatever I want....any suggestions on what I should shoot for?

Any tips or suggetions would be great.... I've never set up all these angle before....

DRJDVM's '69 · #2 04-26-2010, 09:51 AM

One other angle I had questions on...the lower shock mount bracket that attaches to the rearend

The upper shock mount brackett is not at 90 to the ground...its tilted forward at the top by about 10 degrees....so if I do the lower bracket at 90 degress, these wont be on the same plane....should I basically tilt the lower bracket so it mimics the upper bracekt slope?

If the top mount is 80 degress and the lower is 90, isnt that gonna put alot of stress on the shock during its travel?

Its on Air Ride....so I'm doing all this at ride height, but obviously it will change alittle as I raise and lower the car.

**GregWeld** · #3 04-26-2010, 11:04 AM

Ned -- on the motor angle -- you got it. Most everything I've ever worked on is at 3* down at the tailshaft.

When mocking up -- don't forget your other angle -- which is CENTERLINE...

AND

Don't forget to mock up using your urethane mount. A guy I know (not me!) built a whole tranny mount and forgot to include the mount...

SECOND QUESTION:

After you set your motor/tranny - Get your pinion angle set to "match" (parallel plane). Watch your centerline. (BTW - Some Mopars offset the engine... I would assume yours to be on center?

The shock mounts need to be the same angle. The shock would not be happy trying to bend. Easy way to set height and get that angle -- get yourself some square tubing - set up your ride height -- and that will also locate the axle perches. Bolt them up to the mount and tack weld. Don't forget to space the square tubing off the mounts the same amount as your "shocks" will be etc. Also make sure whether or not you want them 90* or at a 15* angle (to the axle as in bottom of the shock towards the tires etc) etc.

**GregWeld** · #4 04-26-2010, 11:10 AM

Just re-read your post --- that's "weird" that the upper mount is "forward" by 10* -- there must be a reason for that? Are you checking that with some bushings etc -- because the top and bottom shock mounting needs to be spaced off the actual mounting point...

I would be mounting the air bag - or whatever you're going to use - to the top mount - and take a good look at interference issues - and then also the "degrees" etc and where the bottom is going to "fall/land"... and then check your bottom mount and how that will land.

The WidowMaker · #5 04-26-2010, 11:35 AM

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 · #6 04-26-2010, 12:07 PM

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** · #7 04-26-2010, 04:20 PM

Quote:

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 · #8 04-26-2010, 04:56 PM

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** · #9 04-26-2010, 05:21 PM

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** · #10 04-26-2010, 05:24 PM

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!!