I dropped the powertrain in yesterday morning. I am very please with how it turned out. The trans x-member brackets are in the same location as the factory FJ/HJ60 would be, only about 3/8" lower to give a little more firewall clearance, and allow me to get the engine up a little higher in the engine bay.
The shifter ended up nicely centered in the opening...
I also began taking a closer look at the suspension. The good news, is that there is plenty of room for the rear links under the truck, so I should be able to get the geometry I want. The difficult part is going to be making room for the coils, and trying to keep the lift of the springs consistent with the lift of the truck. I have all four upper spring mounts that were cut out of an 80 series with hopes I could modify them to fit on the 62 chassis. Unfortunately, they're bulky, so I may end up having to fabricate new ones. Here are some preliminary observations:
- Rear Suspension -
The plan is to inboard the coils in the rear for two reasons. There is no room on the axles out side the frame rails, and if they were mounted directly under the frame, stock 80 springs would probably provide 4-5 inches of lift, which is way too tall for a minimum height. Due to the design of the fuel tank, and the offset of the diff, the passenger side is a little tighter in space than the driver side, so i'll be focusing on that side.
The passenger side...
the driver side...
In an 80 series the OMEJ coils are about 16" tall installed, and I'll assume it will be about the same in a 60. On my HJ with is probably close to stock height, there is about 11.5 inches from the top of the axle housing, to the top of the frame rail, or a difference of 4.5". So Ideally, for 4" of lift I'll need to mount the springs so that the tops are 0.5" above the top of the frame and flush with the top of the axle housing.
That brings me to the lower spring mount on the axle side. The diff lock mechanism also creates a bit of a problem because it exactly where the the lower spring mount needs to be. I'll probably have to mount the coil higher than flush to make room. The good news is i will be able to incorporate a protective cover for the mechanism, but I'll probably end up with 5" of lift with the 4" coils. I'm trying to find some one local to trade me for a set of non-J or 2.5-3" coils.
The round x-member with shock mounts is strangely shaped and not symmetrical so it will probably be cut out and replaced by straight square tubing. This will make it easier to incorporate it with the upper spring mounts, and maybe move it forward slightly for a little more space. The stock bump stops indicate the axle's location and ideally where the coils will be centered. So you can see it will be a tight squeeze to get the coils where I want them centered directly over the axle and not interfere with the fuel tank. I did a couple very crude moment calculations to see how the links would be affected if I had to offset the coils forward of the center of the axle. Feel free to check my math...
- Assumptions -
Load on axle: 3000 lbs
Moment arm of upper links from center of axle: 8"
If the springs are offset 2" forward of center, the 3000 lbs load would be create 500 ft-lbs moment at the axle, or a compressive force of about 750 lbs at the upper links. a 1" offset generates a 250 ft-lbs moment or 375 lbs of force on the upper links. This means that the upper links would have to support 375-750lbs all the time, just to overcome the moment generated by the vertical loading, plus the additional forces due to axle wrap from the powertrain. This is not helpful in minimizing fatigue of the links and joints. I'll need the springs to be as close to centered as possible, which means I may need to lower the upper coil mounts to do so.
- Front Suspension -
Up front the coils will be outboard of the frame. Here there is plenty of vertical mounting space, but due to the engine sump and steering, the link geometry will be more difficult. Another issue is the steering gear which makes it difficult to mount the coil directly above the axle on the driver side. And since the front will be a 3-link, there will only be 1 upper link to resist the moment if the springs are offset. The good news is that there appear to be enough room that the steering action of the knuckle will not be affected.
So in summary, mounting the coils is going to be a challenge. I need to spend some more time looking at it and maybe make a couple cardboard templates before I actually start cutting to make sure I can do what I want. Unfortunately, time is not on my side right now either, and this is not something I will want to rush. I just graduated so I'll need to move soon and think about getting a job. Worst case scenario is I keep the leafs for now, get the truck back on the road, and do the suspension as a phase 2 build later when i have more time... we'll see.