Project Hellraiser 4

Page 18


Previous Update

Another year gone by means it's time for a year end update.  I finally had an opportunity to weigh the buggy, in the new 4 seater configuration with the new 14bolt axle it tipped the scales at 3844lbs. This may seem like a lot but I actually came within a 100lbs off Jack & Dennis's 2 seater buggies despite my boat anchor of a motor. I have since trimmed 14lbs off by shortening my side panels for better visibility out front but there is no way to cut much more and Jack's will only get lighter once he goes to all aluminum suspension links. 

As you may recall I installed my sticky Maxxis Creppy Crawlers at the start of 2007, their break in run coming just 1 week before MLK weekend.  I am happy to report even after a year of hard use I have roughly half the tread left.  The sidewalls are also holding up well with only a few gouges showing and plenty of sidewall tread left.  At this point with my old Iroks I had flipped the tires to get a fresh sidewall on the outside.

While I was changing out the differential fluids I took the opportunity to inspect the rear ring and pinion to see how the gears were wearing in (this was my first solo gear setup).  The pattern looked good.

I also checked out the condition of the rear axle splines, as you can see there was no twist evident.  I feel that the length of these 14 bolt shafts really helps them take a load without twisting the splines. My previous axle had much shorter shafts and while they were a slightly stronger alloy than stock I still managed to put a slight twist in the splines after a few runs. 

My front drive shaft wasn't doing so well.  I let Jesse at High Angle Driveline talk me into using .095 wall tubing for the lower part of my two piece driveshaft and that just doesn't cut it down here.  I found a piece of .188 wall DOM tubing and took the shaft down to a local shop (Master Shaft), they machined the .188 wall tubing to work with the stock spicer ends. I also had them make me a spare front shaft. At this point I think the weak point will be the yoke on the differential but it doesn't hurt to be prepared, especially if you do a lot of road trips like our club does.

One project I need to tackle in the future is to replace the skid plate.  The existing 3/8" aluminum skid plate has served me well for the past 3 years but it is starting to bow in pretty good. If I can find another piece of scrap aluminum I will most likely go that route again as the weight savings is pretty substantially compared to a steel belly plate.

I treated the buggy to 100 feet of new winch rope from A to Z Fabrication.  The 3/8 Amsteel rope came with a crushproof thimble which I managed to crush on the first outing as the rock I had attached the winch rope to rolled onto the rope. Other than that the rope has worked flawlessly and it has been getting quite a workout lately. 

The last little bit of carnage secures my place as the BTG 2007 Carnage Champ :)  Somewhere in late November or early December I chipped some of the teeth off of my TerraLow 4:1 gear set.  From time to time I would hear a popping noise coming from inside of the buggy which I chalked up to the sway bar hitting one of the suspension links. Fast forward to the last trail ride in December when a piece of the broken gears gets caught between the some of the rotating gears causing the transfer case housing to crack.

Hindsight is always 20/20 and I should have pulled the inspection cover on the transfer case earlier which could have saved the case.

My plan to beef up this crucial part of the buggy is to replace the case with a Stak D300 replace-a-case, then replace the broken Terra Low gear set with the larger and more expensive LoMax 4:1 gear set (which are supposed to be bigger than the gears found in the Atlas II). Ideally an Atlas or Stak would have been nice but fitting either of these transfer cases requires some re-working of my internal tubing which was originally setup for a Toyota drive train. More info on this swap coming shortly.  

Update 1-9-07

The UPS man dropped off 6 packages yesterday. Cary at CT Performance, Inc got this thing shipped out same day. I cleared off an extra workbench and unpacked all the goodies. I ordered the replace-a-case, a new 4:1 gear set, a new rear output (thought I damaged my old one but turned out it was fine) and one of their universal shifter kits. I also got a special front output flange bored out for the larger bearing used on my JB Conversions 32 spline front output shaft.

As you can see the case is a two piece design so it's going to be way more rigid than the stock 300 case thanks to not having a huge hole cut in it for an inspection cover. The thinnest part of the Stak D300 case is above the shifter rods and it's still thicker than most of the original D300 case.

Due to the two piece design, assembly has been much more straight forward as well. The instructions they give you have no pictures and are just two pages (which freaked me out at first). I had a hard enough time installing my 32 spline outputs, rebuild kit and gears into the original case with about 30 pages of instructions and tons of pictures. Since the case is split in two you now just drop stuff on in order.

The two case halves utilize a pair of dowels to locate them in relation to each other.  For sealing a piece of o-ring cord is set into a groove which follows the contour of the case.   This should address my one complaint against the old Dana 300, I could never get it to not weep oil.

Stak isn't making their own gears for this case yet so the box came with a set of LoMax 4:1 gears. These things are said to be bigger than the gears in an Atlas II, they are definitely bigger than the gear set I had in their before (old set on the left in the pics) so I feel this will be an upgrade in that department as well.

The workbench in the left picture has all the new parts, the one in the right picture has all the parts from the old case, somehow this will end up as one case.

My progress after a few hours, there's only a few lines of directions left before I bolt the case together.

I finished the case assembly the next evening and moved on to set the bearing preload for the front output shaft.  This is done via some set screws in the bearing cover at the rear of the case. the stock 300 setup used shim plates under the cover which made it hard to get a good seal.

next I weighed the case with the flanges installed and came up with 89lbs, just 3lbs more than the stock D300.

The Stak case is drilled with extra mounting holes so a clocking ring is not needed but I have to re-use mine to maintain the transmission/transfer case spacing.  When I went to mount the clocking ring I noticed the mounting holes didn't line up.  I gave up that evening and called Stak in the morning after e-mailing them a picture of the issue. 

When I contacted them the next day they informed me that I had the first passenger side drop replace-a-case and that there was a problem with the hole pattern being 180 out.  The fastest way to fix it was for them to make me a custom clocking ring to correct the pattern and provide the .75" spacing my old ring did (I could have gotten a new front case half but that would have taken a while to produce). As a testament to their good customer service they were going to machine the new ring and ship it next day which satisfied me.  Future buyers of this case will have the correct hole pattern in it and the drivers side drop isn't affected by this issue. 

Since I don't run a speedometer I decided to eliminate the speedometer gears which left a hole in the rear output housing that needed to be filled. A few hours work on the lathe and mill resulted in this lightweight aluminum plug that uses the original o-ring for a seal and the original retaining clip to hold it in place.

The new clocking ring/adapter arrived Monday, just a few days late.  I was a little concerned that the hole spacing was pretty wide compared to clocking ring I was using but I figured between the clocking hole pattern in the case and clocking hole pattern in the adapter I should be able to get really close to what I had.  As it turns out I could only find one position that lined up all 6 mounting holes between the case and adapter.  After a few test fits I discovered the best I could do was either higher or low than what I had.  

The next thing I tried was rotating the ring on the case to try and get it as close as possible to what my old ring looked like. the above positioning looked close but only 5 mounting holes lined up between the case and adapter. I could fix that by counter boring one of the clocking holes so I tried test fitting it in the rig only to discover one of the top and bottom mounting studs were not engaging.  After another couple hours of fiddling around with trying to get the clocking where I needed it I gave up for the night. I will say I got a good workout bench pressing 90 lbs from the floor to my chest, then to full arm extension, then up another 6-8 inches while trying to engage the output shaft of the transmission......

the next day I went back to the clocking position that lined up all the mounting holes and decided to try and work from there. After some evaluation I had two options, too high or too low.

Too low presented a number of big problems the largest of which was the interference between the front output flange and transmission cross member.  The cross member also hit the case, the case hit the belly pan and the front carrier bearing was no longer lined up.

The too high option causes driveshaft clearance and binding problems up front and presents a slight interference between the shifter mounting plate and the front seat mount cross member.   

I chose the too high option. The driveshaft issue will require me to cut out the existing carrier bearing mount and re-position it up and over to the passenger side.  This will cause the front driveshaft to bind at full droop as I discovered when I originally setup the buggy.  I will have to run a limit strap on the passenger side to keep the driveshaft angles within limits. Another unknown is how much will; the front shaft vibrate.  It looks like I will be adding quite a few degrees at the u-joint on the front output.

The shifter mounting was the one bit of fabrication I expected and it turned out to be the easiest.  the first part that gets attached is this shifter mounting plate which hit the front seat cross member.  A little work with the grinder cleared up that interference.

I then tied the cross members back together with a small brace.  

This is a picture of the installed Stak universal shifter assembly and it has a bunch of appealing advantages over the stock D300 shifters. The biggest advantage is the throw which is maybe a 3rd of what the throw was on the D300 shifters.  This means you can fit them into a much tighter space or in my case, re-coup some legroom by moving the shifters away from the front seat.  For reference I would guess the shifters move maybe a half inch to an inch between gates.  I know my stock shifters went from resting on the passenger seat to hitting the intake elbow.

The other nice thing is the setups adjustability.  StaK gives you a long piece of threaded rod and a mounting tube which you cut down to suit, this sets the distance from the shifter mounting plate and shifter pivot point.  You an further adjust the angle of the shifters front to back with the shift linkages and the angle of the whole assembly side to side by loosening the nuts at the ends of the mounting tube.  

Update 1-28-08 - Round two.  The new front case half arrived to late to get put in for our MLK weekend run so I had to pull everything back apart afterwards to install it.  The new front case has the correct front hole pattern so my original clocking ring can be used. While I had the case apart I also wanted to investigate why the shifting was so difficult and why the rear output would sometimes pop out of gear in 4 low.

The picture above shows the one modification I did to the front case half, I added an oil level sight.  I chose to do this on the front because it is easily visible from the cab.

Stak had told me to look at the shift levers as the source of the shifting issues and sure enough, the shift forks were not square in relationship to the shift rails.  In fact, they were far enough out that the rear shift fork had been cut into by one of the gears about .06".

The front shift fork was also out and was causing the front shift collar to touch the intermediate gears.

The only solution I could see was to cut shift fork collar off of the fork and re-weld.  Another thing I noticed was the shift forks were loose when I pulled them from the case despite me using loctite on the set screw that locates the shift fork in relation to the shift rail. StaK uses a much smaller set screw than the stock Dana 300 which I feel is the source of the problem as the set screw is much smaller than the locating hole in the shift rail and does not dovetail into it like the stock 300 setup.  

Fixturing the shift rail to the shift fork was difficult with the materials I had on hand at home but I eventually got the shift fork close to perpendicular to the shift rail.  I also chose to tack weld the shift for to the rail once I confirmed my positioning was so I was no longer relying on the small set screw to hold the shift fork in place.  Upon re-assembling the case my modification were immediately validated as I could now shift the case by just gently tugging on the shift rails (without the ball detent springs/balls installed).  Previously I had to use the levers to get enough mechanical advantage to shift the case and even then the rear output required a lot of jiggling to get it to engage/disengage.

So , the big question is would I go this route again?  My answer is no, not if I knew I were getting the first one.  For the price I paid for all of the parts and time I spent getting the box to work correctly it would have been cheaper to get a 2 or 3 speed box and modify the chassis to make it work.  If I knew Stak had fixed the hole pattern issue (done), came up with a better fixture for welding their shift forks together so they were drop in and beefed up the set screw which locates the shift fork then my answer would lean more towards yes.  This setup is smaller and lighter than a full blown StaK or Atlas and from the looks of the parts inside should be as strong making for a compelling small transfer case option which is what I was original after but without all the extra R&D..

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