DAY 5
EXTREME BUILDUP 2000 Project 2
Damian's 1970 800a
Now that the front end is pretty much wrapped up, its time to spend some quality time
with the rear axle. The first thing we did was cut off those spring perches and weld/grind
everything smooth. With the ¼ elliptic conversion the spring mounts to the axle via one of
the eyehole. For those of you not entirely sure about the workings of the quarter elliptic
conversion, here is a brief description.
A quarter elliptic is a fairly complex monster of a conversion. It consists of custom making
a spring pack that only attaches to one point on the frame. “What?” you may think, “How
does that work?” Well you standard leaf springs attach to two points and since there are
two packs, you have a total of four attachments, this gives foreword to back support and
also side to side. Now cut the two rear mounts away, all of a sudden you have a ton of
flex but a useless suspension.
The quarter elliptic is similar to this “analogy”. If you were to take your leaf packs and cut
about 5” off center, you would be left with about 60% of a full pack. Now, attach the
thick part to the frame (where the front spring hanger is) such that the pack curves
downward and at the bottom is the eyehole (where the shackle used to mount). What you
have now is a VERY unstable situation. If you were to now connect the axle to this “half
spring” and you would have all the flex you would ever want but your chances of driving
anywhere is ZERO. The spring pack will “push” down, but will no longer hold the axle in
place.
The reason is that you’ve lost all forward-to-back and side-to-side stability. This is why
we MUST build a 3 or 4-link suspension to give stability to the rear suspension. And that
is where we are now. Oh, and by the way, it is important that you finish the front end
before starting on the rear. Why? Because you need to know how high to build the rear
(which is completely adjustable).
Trick Number One - Mounting the new spring to the axle. This is a weird connection,
remember that the spring likes to flex up and down, but doesn’t like twisting. If the packs
were rigidly mounted to the axle, it would have to twist. Here is the picture first, and the
explanation follows.
Can you figure this one out? Sure you can. We used the original rear shackles, cut them in
half and built a bushing onto one end. This way the axle can twist and the spring will pivot
on the bushing. No twist, only flex (up and down). Look closely at that last picture .The
shackle is roughly in the same place where it will be when we are finished.
PLANS
| Day 1
| Day 2
| Day 3
| Day 4
| Day 5
| Day 6
| Day 7
| Day 8
| Day 9
| Day 10
| Day 11
| Day 12
| Day 13
|
