Hey Everyone, My build thread has been stagnant for a little bit. As a young man with limited income, it sometimes gets hard to save enough to get parts together. Anyway, a few months have p***ed and I just dumped a few paychecks into parts that just came in. So I got my rear end from Moser, Posies rear buggy springs, Perches and Shackles from Pete and Jakes, as well as their ladder bars. This is my first car, so I still feel a little lost getting this all together; so I just wanna make sure I got this right before I weld it in and **** it up. So this is my plan, please let me know if I got anything wrong. First I gotta finish boxing the frame; gonna do that today and tomorrow. Then I'm gonna level the frame. Gonna set the rear end under the rear springs, get everything center, then tilt the rear end up until the pinion is 5 degrees up. There seems to be some debate about this, is 5 degree pinion angle ok? There is no weight on the car, so I'm worried about welding the perches in for pinion angle. I read in another thread to use ratchet straps to compress the spring to ride height, but how do I know how much compression will be ride height? Also, how would I get the springs to compress without snapping tack welds off the perches? The pinion angle stuff and setting ride height before welding is my only real road block right now. Also, for the ladder bars. Should the ladder bar crossmember be closer to the top of the frame, bottom, or middle? Does it matter? I'm not sure how the driveshaft is gonna be yet, but is it supposed to go over or under? I appreciate the help guys...I'll keep browsing the the forum for answers, but whatever gems of knowledge you guys have to share is really appreciated.
OK, before you weld anything, make sure you know what the spring perches hole center to hole center is for the spring you bought (when preloaded/spread open with a spreader tool, i will add this is ridiculously dangerous if you dont know how to do it, installing rear A springs is no joke) , if you weld them in with no pre-load in the spring, the shackles will bottom out on the perches when the weight of the car is applied. Pinion angle is dependent with angle of the output shaft of the transmission, mind you the shaft itself and not the case or tail housing, the pinion shaft and trans output shaft need to be as close to paralel as possible with the car weight supported by the suspension. As far as the ladder bars go, I would feel good with positioning them with the crossmember centered, as close to paralel with the frame possible with slight triangulation for axle centering. I hope @gimpyshotrods chimes in, his way of explaining this sort of thing is much better than mine.
For sure, I get all that. The thing I'm having trouble with is, how to figure out how much the pinion angle is going to change once the weight of the car is on the spring. It seems like I can't figure out the final pinion angle without having all the weight on, but I can't but any weight on the car until the suspension is on. So which comes first? Really, I'm just trying to figure out next steps, as I think I got all the parts I need to move forward. Should I worry about getting the motor / trans in before I worry about the rear end?
Pinion and tailshaft are parallel, w/a 3* (ideal) driveshaft angle offset. So that the u-joints lube and shuttle the grease, and spread the loading out. You could set up your final desired driving height, w/no springs, etc, and adjust/shim (the spring) to reproduce it later. Float an empty block/bell/trans in place if poss.
Do not attempt to set your pinion angle exactly right now. It cannot be done without the full weight of the completely built car on the suspension. Adjust clevis ends of the ladder bars so that half of the thread, less the diameter of the thread section is sticking out, not including the nut. In other words, if the threaded shaft of the clevis is 5/8", make sure you never have less than 5/8" of thread in the hole in the end of the tube. Use the lock nuts to set them there. Tack weld the ladder bar brackets to the axle housing at 3º. Leave them there until the car is more done. As for the angle of the ladder bars, put the bottom tubes parallel with the ground. Set your crossmember to put them there. Put the spring perches on with really good tack welds, with the through holes set parallel with the ground. Make sure that they are set at the correct distance. You will have to wait to finalize everything until you have more weight on the ch***is. Take to heart what Pocket Nick said about spring safety. Metal springs under load store enough energy to end your life in a heartbeat.
Step 1 - Measure your ch***is diagonally. Make sure it's diagonally square to within a mm or 2. Step 2 - Build a ch***is jig to weld your ch***is into so that when you box it it doesn't warp. Step 3 - Continue with above help. Edit: Here's a picture for reference. If you make a jig, it doesn't have to be super fancy. Just a length of 100x100mm box section with some cross bits, uprights and i welded small 25x25mm pieces onto the inside of the uprights to hold the ch***is at a level hight. Then tack it into the jig and when you box your ch***is just weld it up nice and slow, do an inch at a time and then go to the next corner, do another inch.. next corner.. another.. and so on. I ended up adding rotisserie ends onto this and built stands to be able to rotate it without pulling the ch***is out but that was a bit overkill really..
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