Saturday, January 17, 2009

Pumpkin Interference

No, not the gourd - the differential case is sometimes known as the "pumpkin". As I was preparing to put the ElectroJeep back in the garage for the miscellaneous final things that need to be done, I took a look at the front differential - I expected the springs / shocks would have settled some after going over the curbs, etc. And I was right. The motor mount was resting on the front differential. This is very bad - going over a bump with any significant force would cause serious damage. In fact, even the 100 gentle feet I drove caused damage to the mount - see the lower left corner - bent and scarred (this picture was taken with the Jeep jacked up, so the front axle is dangling):


So, the whole thing needs to move up. I have about an inch of clearance on top:


I also need to move the crossmember toward the rear of the Jeep. This causes, umm, interesting challenges if I am to use the original motor mounting points. Here is one design, showing a heavy 1" box tubing framework that pushes the hanging point toward the face of the motor (it would all ride on a 1/2" threaded rod, shown, that runs the whole length of the assembly):


I would also have to remove most of the aluminum foot on the driver's side of the motor (highlighted in blue here). This would give me nearly two inches of clearance - and I could put a rubber "bump stop" or something down there in case of an extreme bump.

The other option, not shown, would be to rotate the motor 180 degrees so the "foot" is on top, and the motor is hanging from a support stretched across / between the two motor mounting points. But the size of the foot means that there would not be as much clearance between the differential and the motor. And I think I need all the clearance I can get...

4 comments:

Anonymous said...

Ross, It's the guy from Florida who has done this before. This might me remedied relatively easily. The bump stops for the front axle can be extended by putting a one inch puck on the axle side inside the spring. This will limit up-travel of the axle. Drill out a hole in the center of the axle end of the spring mount and tap it. There are several of these available on the aftermarket for 4X4 lift kits. I made my own. The motor should have enough clearance to be raised 1 inch more than in stock position. Just be careful to adjust (shim) the rear pinion angle to match (stay paralel to) the angle of the rear yoke of the T-case. You can probably also shove the whole assembly back a bit. It is not that hard to have the length of the driveshafts changed. You can try these things before cutting off the mounting surface of the motor. I took out the springs and shocks and sway bar and stuck a jack under the axle and ran it through its range to test mods before putting it all back together again. Now you see part of the reason I did a 2wd.
mmkramp@aol.com

Anonymous said...

another option would be to simply put a 2-3" lift kit on the jeep and extend the bumpstops.

Ross Cunniff said...

Thanks - good suggestions. I have not decided anything yet - measure twice, cut once...

I like the idea of moving the whole thing back. Not sure how much room I have with the bellhousing vs. the body - I'll go measure. Ideally, I could move it back to use the current mount on the *rear* of the motor mounts, and just drill one new hole on either side for the transmission mounting plate. I'll take some measurements and think about it...

The Jeep is *already* "lifted" by 2.5" but the weight of the batteries has removed most of that (I'm about to install add-a-leafs in the back because of that).

Anonymous said...

Ross, If you did rotate the motor 180 deg could you then secure mounts to the side of the motor feet that is facing downward. That way all that would be sticking up would be the head of a bolt. Should fit within your 1" of clearance.
Roger