Project BMP

Page 21



Previous Page

As you know in last weeks update I was able to drive the buggy around on the street.  It was good timing because Tuesday of the following week our new child arrived.  Everything went well, he's healthy and mom was doing good.  I took the rest of the week off to stay at the hospital and then later at home with the new family.   By Saturday things were settled down enough so I could get some stuff done on the buggy.  First up was fabricating an exhaust system. 

I planned to use a 10" Supertrapp muffler but after buying it was worried about the noise level.  In the end I decided to keep the large glass pack I had in the system towards the middle, then use the Supertrapp out back.  This combo gives the motor a nice mellow tone.  My friend Brian bent up the exhaust tubes at ATD Automotive Repair &Fabrication (623-780-4901).  In addition to repair work they also do a lot of custom fabrication from cage work to motor work.

Once the exhaust was installed we used the forklift to check out the clearances when the axles were articulated.  I found a few small issues.  In the second picture you can see the bump stop just barely hits the hydro cylinder fitting.  I designed the bump stops for on-road usage (jumps) and intended for the shock to bottom out off-road under extreme articulation.  It looks like I can just rotate the cylinder a bit to gain a little more clearance.

Out back I discovered a bigger issue in the form of this interference between the shock and swaybar.  The heim joint is barely touching the shock shaft moves away as the shock comes back down and the axle goes back to level but it does just clip the shock body.  I plan on moving the heims back on the swaybar arms about a 1/2".  I will also move the arms inboard slightly by cutting down the mounting tube on both ends.


Picking up the front end,  after this I drove it around a bit on the street to get a feel for the rig.  The swaybar works well and body roll is pretty much a non-issue, there is some but nothing that would keep me from corning hard at speed. 

It also looks like my braking problem has been solved.  One thing I found was a vacuum leak on one of the lines that was supposed to go to the old charcoal canister (which I am not running). I also went back to the stock 7/8" bore Samurai master cylinder after reading this article which discusses the effects of swapping out bigger master cylinders. the gist of it was that installing a bigger bore master cylinder basically causes you to lose some leverage on the braking system, this combined with my having to shorten the pedals 5" made it very hard to push on the pedal and get a lot of braking force.  With the stock master cylinder installed I can lock up the rears on pavement so I may add a proportioning valve down the road.

As far as gearing, the new Toyota t-cases are different that the old Samurai case in respect to high range gearing, the old Samurai case had about a 1.81:1 gear reduction in high.  With the new setup being 1:1 in high the motor is really going to have to work to pull bigger tires.  I do notice the motor being more bogged down till about 2000 rpms and then it picks up speed pretty good. This means I'll need to keep the 5.29 gears in the differentials, while switching to 4:10's down the road would add some more reliability, I think the further increase in gear ratio would really make high range performance suffer. Low range performance is a different story.  With just the rear case engaged in low (4.7:1), the rig feels about like it did when I had my 6:1 gear set installed in the Samurai case.  Once I also engage the front case in low the rig hardly moves even at the redline in 1st, the effect gear reduction in this configuration is 10.7:1.  I can't wait to play around with the new gearing options in the rocks.

One setback was experienced when I noticed my engine fan had not cut on, I went to jiggle the wires and noticed smoke coming from the controller.  Something was shorted out because we couldn't kill the motor without pulling the distributor wires.  The thermostat control unit on the Flex-a-Lite fan was pretty much toast so for now I hardwired the fan to stay on with the ignition.  I know a few people who have had the same problem occur but most of them got a few runs in before their temperature controller self-destructed.

On Sunday I finalized the welds on my exhaust pipes and fabricated a small hanger to secure the large glasspack.  Next I fabricated a small dash panel and installed the gauges.  I will be running a tachometer, voltmeter, oil pressure and water temperature gauge.

Update 12-21-04

The swaybar has been modified.  I pressed a plug into the last hole in the arm and then drilled a new mounting hole 5/8" back. I also cut down both ends of the mounting tube to allow me to move the arms in 1/8" on each side. 

The rear limit strap was installed.  To keep it away from the bump stop I needed to space it back a ways so I came up with this mount for the upper axle housing built from some of the extra tabs I had.

I also fabricated a small mounting bracket for the winch controller.  It is within easy reach of the driver  and clipped in via a small broom holding clamp.  I stole this idea from some of the guys in the club.

One other thing I changed was the switch from running a sealed hydraulic reservoir to a vented reservoir.  The orange air line on the top of the reservoir runs to the passenger side of the engine compartment to a small vented catch can.  The catch can was made from a piece of 1.00 x .120 tubing, I capped both ends.  The bottom cap was threaded for 1/4 npt and the top cap was made on a lathe in the shape of a hose nipple so I could slide a small air filter on it.  I decided to try this after reading this thread on the PBBs .  My last power steering pump was really noisy from the get go and with a single ended ram the fluid level in the reservoir changes quite a bit as you steer from side to side (which means pressure build up).  My running a double ended  ram now may have already eliminated most of the pressure build up issue due to the fluid level not changing but I figured I would try it anyways.

Update 12-23-04

I think I can call the interior done.  I mounted the line lock switch on the dash panel and made a trim piece to tie the two upper dash panel plates together on the passenger side.  Down the road I would like to add an LED indicator for the line lock switch.

With the dash done I turned my attention to the body panels.  They are made from .06 clear lexan which will be painted from the inside.  I used a sheet metal nibbler to cut the main shape, then a jigsaw for some of the small details (like the footholes).

Here's some pictures which show the approach and departure angles.  My goal was 90 degree approach and departure angle with 39" tires. With my 37" tires on there it looks like the front is about 85 degrees and the rear looks to be 90 degrees.

Update 12-24-04

The last big item I needed was a front driveshaft.  The budget for the project has been stretched pretty thin so the $300 I was quoted from various shops was a little hard to swallow.  I ended up using the ends from two rear driveshafts and a short section of tube to create the required driveshaft.  Total cost was approximately $15 in steel and a small favor.  The tubing I used is roughly 3/8" wall.  The ID is slightly smaller than the OD of the slip yoke from the stock shaft.  I was able to sand the ID of the tube down with my dremel and the slip yoke slid right in.  For the other end I had to have a machine shop turn the ID of the tube down to 2.52 to allow the u-joint and short section of tube to slide inside of it.  I set the length so I would have approx. 1.75" of slip inward and about 3" of slip outward. 

The roof panel is now cut and mounted up top, I used .080 thick 5052 aluminum. Still working on the hood.  I also managed to get the side panels painted and mounted.

 Next Page - Page 22