No, I’m not talking about the weather. While spring has definitely sprung in southern Arizona, it may or may not have sprung where you are. I’m talking about the JeepMonster and the fact that it’s *finally* (partly) resting on actual springs which are (temporarily) attached to the frame and back axles!
The motor mounts are also in (sort of – they’re tack-welded and need more reinforcement, but they’re actually holding up the engine), which brings me to a good-news-bad-news moment. The good news is that the middle driveshaft will actually be a little bit longer than I had calculated, so as it cycles up and down with the middle-axle suspension, the driveline angles will be a tad less than I had thought. The bad news is that the reduction in up-and-down angularity will be offset by a side-to-side angle.
It seems that the engine/transmission/transfer case assembly was offset to the driver’s side of my Jeep when I had it put in originally. I *believe* this was the case with the actual, original 1961 drivetrain, too, but I’m not 100% sure on that. What I do know is that I failed to account for this offset, and the fact that the powertrain is centered in the new frame, when I was measuring and calculating for the axle differentials and where they should be placed on the axles. The plan had been to have all of the driveshaft yokes – back axle, middle axle, transfer case, and front axle – be in a straight line fore and aft so there wouldn’t be any side-to-side angle in the u-joints. While I got it right for the middle and back axles (see picture below, where the two pinion yokes are directly above the floor’s expansion joint), you can see that the transfer-case yoke (in the foreground) is quite definitely *not* on the same line. It’s not a big deal; I ran the CJ-5 with a similar side-to-side angle for 10 years without a problem. But when they’re supposed to be in line and the *aren’t*, well, you just have to live with it.
I don’t have a photo of it, but the front axle yoke is even farther off – but in the other direction! It’s much closer to the frame’s centerline than the transfer-case yoke. Again, I don’t think it’s a problem, but it adds more angularity to the u-joints and could, i suppose, shorten their life if the angle gets too great. But I don’t think anything is in the danger zone. I don’t have any excuse for this mismeasurement – I just goofed somewhere.
Another change is that the rear suspension is now spring-under-axle. I don’t remember whether any pictures in previous posts showed it clearly, but up until this past weekend, the springs had been on top of the axles – which made the whole frame (and everything attached to it) sit five inches higher than it does now. Obviously, you need sufficient height to clear the tires and axles, but too much is not good. As it sits now, it’s too low, which also isn’t good – there’s no room for the back axles to move up before they hit the frame. So I’m going to get a set of springs that’ll lift the frame 2 to 3 inches from its current height. That’ll still leave it a couple of inches lower than it was before.
Here’s a shot of the frame, engine and axles, looking forward from the back axle.
In other news, I went to the Overland Expo in Mormon Lake (about 30 miles from Flagstaff) this past weekend. I had some vendors I was specifically looking for, who had been there last year – for things like bumper pieces and a multiple-battery management system – but they weren’t there. I *did* talk to the Phoenix-based company that I’m going to buy my expedition / camping trailer from, and got some of my questions answered (like could they modify the frame to include a winch mount at the back, and how good was the water resistance of the doors / hatches), so that was good. And I got lots of new literature to look at, which is also good.
But the most exciting display, in my opinion, was the one that actually had one of the Jeeps that inspired JeepMonster! It’s called a JK6 and is a (very heavily) modified Jeep JK Wrangler Unlimited. I wish the ground had been dry, instead of soaked from snow and rain the day before, because I *really* wanted to crawl under it and see how the drivetrain was set up. The person manning the display confirmed that the middle axle was a pass-through design for a Ford 9-inch axle, and also that Tyrant wouldn’t be able to modify a 2-door Wrangler because it would be too short. But there it was, in actual reality:
I was surprised at the relatively small tire size. The Wrangler runs on 16-inch wheels, and these tires were metric, so I don’t remember what their size was (and didn’t write it down), but it looked to me like they were about 33 inches tall. And the back two tires on each side were so close together that I don’t think there’s any possibility of going to a larger size if the owner would want to. But hey. If you have the money to blow on one of these, maybe you don’t want to go places where you might need 35s or 37s.
Now, if you’ll excuse me, I must go order more parts for JeepMonster. It needs lots of things, some of them (like exhaust manifolds and springs) rather urgently so Robert can keep building. 🙂