Shotts' 1997 Lexus "Rock Crawler" buildup:

[Desertdude]

I see where you are now as far as the welding of the plates... and making finer adjustment

I read on Mud after a lengthy search - Rick (Land-tank) has been developing adjustable or user drilled castor plates...

 

[ShottsCruisers]

I see where you are now as far as the welding of the plates... and making finer adjustment

I read on Mud after a lengthy search - Rick (Land-tank) has been developing adjustable or user drilled castor plates...

Ya, I read some of that stuff. I think Slee's focus is right for his bizz. He has 4" plates, 4-inch lifts, and the parts to make it work.

To try and simplify my solution, I've asked for lift specs on a Slee 4" lift from center of the wheel/hub up to the wheel well. I'll compare my no's to Slee's. If I can get to that spot (sure I can) in the front all should work. Then, I have the rear adjusters for the rear as well as all the other Slee 4" parts already on. The only thing different are my springs. That's my thought....plan....of course I'll await results on that CV shaft. Bad? Not bad? We'll see.

Sound resonable?

 

[Desertdude]

Sound resonable?

yup -


I would still question the fact that the diff pinion angle appears to be in the middle of where it should be -

I think I would try an acurately measure both the diff anf transfer case angle this way you will have concrete data for extended help

 

[ShottsCruisers]

yup -


I would still question the fact that the diff pinion angle appears to be in the middle of where it should be -

Probably right. IF however, I have Slee 4" cater plates, the same slee 4" lift amount and his matching CV shaft then things should line up and work.....or his kit wouldn't work either?

I think I would try an acurately measure both the diff anf transfer case angle this way you will have concrete data for extended help

I looked for an inclinometer but have been to busy and sick.

 

[goodtimes]

John, for proper driveline operation, you need to first establish ride height (you should be done with this by now), zero out the pinion angle and transfer case output shaft angles (they should be parallel to each other), then you need to calculate length (u-joint axis to u-joint axis), then calculate the angle that each u-joint will be operating at. If the u-joint operating angle is above 7 degrees, you want to go with a double cardon shaft. This will require a pinion angle change (from stock). So, now adjust your pinion angles. For a linked (coil springs) axle, set your pinion angle about 1 degree below driveshaft angle. For leaf springs, start at 2.5 degrees. Once the pinion angle is set, then recalculate driveshaft length. Correct for castor only after the pinion angles are set. You will be limited on the pinion angle adjustments once you correct for castor.

Since you already corrected for castor, you are in kind of a bind. If you set your front axle up for a DC driveshaft (pinion rotated up, pointing towards the transfer case), you will either need to stick with a DC shaft, or cut your castor correction plates off, and start over. There is nothing wrong with running a DC driveshaft in place of a traditional shaft (assuming you set u-joint angles properly). The only downside is a small increase in rotational mass of the drivetrain, increased cost and increased maintenance (more things to grease).

 

[goodtimes]

Oh, I have a inclinometer (magnetic protractor) here if you want to borrow it (it is stuck to the side of my tool box, about 12" above your CD with the Chiva pics).

 

[ShottsCruisers]

I think I had a good plan of attack on this build. I just got caught up in either:

1. All the trucks vary a bit so things can change.
2. I got a bad CV front Dshaft

I decided on a 4" lift using J-springs. And to keep the excellent ride I figured I'd correct caster. My friend Frank just did the same thing on his LX and no vibrations existed and he used his stock front shaft.

Didn't work for me (possibly because of bad stock U-joints we didn't know about)...so the crap began. I bought each additional item from Slee as he thought I might need. Nothing worked.

1. Slee said CV shaft?
2. Lift the front 20mm more to improve pinion angle
3. Slee said rear control arm adjusts to fix rear angle and dial in
4. Check D-shafts for bad u-joints
5. Replace bad rear U-joints
6. Send CV shaft for testing.

I understand your note and the adjustment process. I do wish there were as many options available for the 80 as there are for your Jeep. For me I had two caster selections...2.5" and 4". I went 4". So, I'm stuck correcting pinion angles using other methods. Bassackwards of your, the standard method.

I'd luv to come by Saturday or whenever to snag that inclinometer and swap CD's. When ya free? I can bring the Lexus so you can eyeball the thing. It is a sight of beauty...too bad it's not usable.

 

[goodtimes]

I'm here all day today (friday), I'll be home after ~7:30pm tomorrow, and I don't know about Sunday...I work 7 - 7, but will probably get together with some people from school to work on a engineering project for a few hours (meaning I'll get home around midnight).

I realize you had very limited options with regards to your castor....my post was more for someone down the road who is researching lifts and comes across your thread.


:wavey:

 

[ShottsCruisers]

OK EXPERTS....I HAVE ANGLE MEASUREMENTS!

Goodtimes really stepped up and checked out my Lexus. With his knowledge and tools I learned a lot. Whiteboard drawings sure helped too. Brian, you rock! Thanks!

Here's what we found out. Now, what do I do next? THANKS!

T/Case front flange is UP 3.5* and T/Case rear flange is DOWN 3.5*
(Is this normal? I'd think they'd be level? His garage was.)

FRONT MEASUREMENT:

T/Case 3.5* UP
Front Pinion 6.5* UP
Slope 9*
So the difference angle is 2.5* which should be just in the working range of the D/C front shaft. (??) He said there's no way a stock shaft would work...we removed it.

He inspected the new DC shaft and believes it is bad. He showed how it is rough in places and that it makes some noise when turning by hand. We did not re-lube it because it's new and it came with problems (noise/vibration) out of the box. I sent it back to Slee today. If it is bad a new one will be sent back.

REAR MEASUREMENT:

T/Case 3.5* DOWN
Rear pinion was 2* UP...we adjusted to 3.5* UP and are driving this way now. It rides smoothly with the rear shaft in only.

So, what should I do next?

A. Put in D/C shaft when a good one returns and see how it goes?
B. Not wait for that. Get working on another solution now because of front geometry (though it might not need more work/lift/whatever)?
C. ?
D. ?

 

[Desertdude]

One thought - if you want to make it perfect and your like you lift hieght - unweld the castor plates and get Rick (landtank) to make you a new set based on your angle needs for the DC shaft ( since you no longer have the OEM shaft)

at least now you know what is going on

damn your posting in 4 places :Wow1:

 

[ShottsCruisers]

One thought - if you want to make it perfect and your like you lift hieght - unweld the castor plates and get Rick (landtank) to make you a new set based on your angle needs for the DC shaft ( since you no longer have the OEM shaft)

at least now you know what is going on

damn your posting in 4 places :Wow1:

Posting is down to two now. :Wow1:

And yes....Rick was a thought. I'll see how he responds. J

 

[goodtimes]

John, I think you should get the driveshaft taken care of first. If you start changing things before you are sure that is or is not the problem, you can create a new problem and you won't be sure what is happening.....take one step at a time. I do like dude's idea about having new castor plates made. If I were in your shoes, I would talk to the guy about having some made, but not actually have it done until you get the driveshaft back and verify that it does or does not work. Plan for the next step, but don't take that step until you finish the first one.

Keep in mind, as you continue to increase the pinion angle, you are also increasing the castor angle....this will eventually start affecting your handling. At what point it becomes unacceptable for you, I have no idea. But as you rotate the axle forward, you will see the steering become sluggish and will require more effort to steer at speed , and it can induce some torque steer (although I would be surprized if you ever noticed....this is more of a problem with FWD cars with high horsepower engines).

As we discussed yesterday, as you move to extremes, these symptoms will become worse and worse. At what point they become unacceptable, is up to you. Just be aware that very rarely will you be able to change one thing to gain an improvement without having a negative effect somewhere else. (for example, rotating your pinion angle up with new castor plates will help u-joint angles but will hurt steering performance). This is why I think you should do the driveshaft first...this keeps things farther from that extreme.

 

[ShottsCruisers]

Yepper. I'm doing nothing until we get the D/C shaft back. Meanwhile...I have a question:

They say when you accellerate/cruise the pinion angles changes (rotates) by 1-2*. The front goes down and the rear goes up they say. What does this mean?

When you hit the gas what happens to the ANGLE OF THE PUMPKIN/FLANGE?

The rear angles UP compared to parked?
The front angles DOWN compared to parked?

I ask because I need to still tune my rear shaft before the DC front comes. It's pretty smooth on gas and when Cruising. Off the gas though it makes some grrr noise at faster speeds. We set the flanges parallel in the rear though that was parked position rather than cruising. I'm trying to figure which way we need to angle the 1-2*. Gracias!

 

[goodtimes]

On standard rotation pinions (like yours), the rear pinion angle will increase under load, and decrease under coast conditions. That is to say, the pumpkin will rotate up (the "companion flange" that the driveshaft bolts to....the part we measured to obtain the pinion angle, moves up). If you are getting noise under coast conditions, you need to move the pinion angle up when parked. Don't go too far (small increments), or you can start seeing problems under load....there is a happy middle ground there somewhere.....just gotta find it.

 

[ShottsCruisers]

On standard rotation pinions (like yours), the rear pinion angle will increase under load, and decrease under coast conditions. That is to say, the pumpkin will rotate up (the "companion flange" that the driveshaft bolts to....the part we measured to obtain the pinion angle, moves up). If you are getting noise under coast conditions, you need to move the pinion angle up when parked. Don't go too far (small increments), or you can start seeing problems under load....there is a happy middle ground there somewhere.....just gotta find it.

Gracias. I'm going to buy a huge wrench like you used and try it myself.