Category Archives: Derby Transmissions - Page 2

The Original Warlord:Pt1

Well, for thise of you that don’t know or never will know, a few years ago i undertook a brainstormed project of the ultimate derby transmission that not only would not break internally or externally…….but would also serve as the main structural member of the center of the car and keep the front end from bending upward.  since it’s inception nearing 3 years ago, many products have been introduced to try and copy it, and none of em have quite gotten there yet. it was ahead of it’s time in the sport of demolition derby and to be quite honest, there may never be a transmission built quite like it ever again due to rules changes and modern times. i will never know for sure but i suspect that this thing eventually led to several rules changes as it inspired drivers/builders to push this area of car building to the next level.  so from here on out is a chronical of the build and the results. enjoyt ans thanx- Bomber 1/24/2012

Stock aluminum bell housing failure  is a very simple case of torsions from the rampant forward-reverse shifting cracking the case. It is a common failure in snow plow trucks for the same reason, as well as trans brake applications in drag racing. However the tailshaft issue has nothing to do with the shift, and has everything to do with having a slider driveshaft and a terrible pitch to the driveline (i.e. chevy V-8 in a crown vic). It is a fact that 70% of rear aluminum case/tailhousing failure come from newer ford installations with chevy engines, and the way these cars bend. i believe it has nothing to do with the length of the tranny itself or a tailshaft hitting the dirt. The failures through my shop that do not come from crown vics usually find themselves with a slider shaft/yoke issue.

374721888 it became obvious that the Brian Nerat one piece cv yoke is the way to go if you need a piece for your slider. i have had many different versions through the shop- even made my own a few years back. Last fall one of my test trannys went out and literally came back in a rubbermaid container in 7 pieces. he used the Nerat yoke. i chucked it in the lathe and was somewhat shocked to have only .003″ of runout. it was literally the only thing from the engine to the rear wheels that made it back undamaged!!

So i decided to see if i could build a tranny that could stand up to a slider shaft explosion- so to speak. Since i sold my drag race car last fall i had to come up with something else to tinker with! the place where i started was the tailhaft housing. i then simply had the simple stratedy to anchor the stronger tailhousing to the back of the engine to take the strain off the transmission case.

Well after pondering a few different directions, i met my Friend Bob Kinney, a retired aerospace engineer. he ran his own machine shop for many years and sold it off, but has a small shop in his barn. Bob claims that there hasn’t been a space schuttle launch in the last 20 years that didn’t have a part he built on board. After work one day late February, i stopped by his shop and had a few beers as we looked at a housing to come up with a design.

383115969To make a long story short, i made a comment along the lines of,”I am not worried about weight just make something that won’t break!”…..and he did. It started as a a piece of 7″X1″ thick solid steel for the flange- and an 8″ long X 4 1/2″ thick solid piece of steel for the length of the housing. It was machined- welded to one piece- then machined some more. when it was all said and done with it weighed 75lbs and felt more like an artillary shell then a tail housing. In machining, there were some funky things that gm did. like the 6 mounting bolts for the housing are not based off the centerline of the tailshaft. And, as anyone who has tried to find one, a common roller bearing to fit a gm yoke as i had intended is not cheap or easy to find. so it retains a stock 1 1/2″ brass bushing for the yoke.

So now what in the hell do i do with this thing i just paid 750$ for? Well i decided that i would build a mid plate to extend between the oil pan and the bottom of the case, similar to a mid plate between the engine and bellhousing. it serves 2 purposes: strengthen the case and help glue the big tailhousing to the back of the case. I first tried using 1/8″ but had to build a second plate out of 1/4″ as the 1/8″ wasn’t near re-did enough to cut the mustard.

Well, now what do i do for a Bell housing? I had heard Brian Nerat was working on a steel bell housing, but decided to work on trying to glue the JW ultrabell onto the tranny better. i found a steel bell housing from an outfit in iowa, but it was over 500$ and to be honest it looked kinda cheesy for what i needed it to do. The ultrabell is a great solution to the torsional stress of derby, but it can still rip off the case behind the pump as the car noses. So i bought an ultrabell and began fitting the mid plate forward beneath the bell housing with the intent of extending it up between the engine-then back over to make a top brace. i never took a picture of this stage of the build as i ended up using the ultrabell for a customers tranny, then shevled the mid plate and tail housing to be forgotten about til this fall. it was time for Spring explosion, so everything got put on hold.

I ran into Brian Nerat at a sporting event….and his new Steel bell housing. To be honest it reminded me more of a charcoal grill for tailgating than a bell housing. but it was the perfect mate to the ridiculously heavy tailhousing i had built…..and affordable. So when i got home with it, i decided to hack off a weld repaired bell housing chevy case. i had built it for full manual shift, more of a drag racer’s set up, but why not!! this project is already in left field as it is! i bolted the tail stock on and cut the mid plate to fit. i was actually somewhat astounded- it almost balanced out from one end to the other!! 387544802 S3700008My friend Kevin Cutler of hillbillyspeedshop had made me this one off custom oil pan a long time ago as a gift, so in a pinch for time, i decided to put his pan on the set up. i had intended to make a 1/4″ custom pan using the mid plate, so the mid plate is the oil pan, but i ran out of time. Metal Mayhem was less than 3 weeks away and i wanted to have this thing done and working. so i buttoned up the mechanicals and put on a coat of paint.

Alright now i have a tranny!! BUT….i still need bracing from the bell housing to the other 3 sides of the tailhousing, and a transmission mount.

Transmission Lines/ Cooler Loop Lines

one of the stupidest and unfortunately frequent failures and major source of burns is a transmission cooler line failure. how many times have you seen a cracked steel line, or better yet fuel line wrapped in duct tape or electrical tape!! also how many times have you put in the “aftermarket” derby hoses and fittings into your case and cracked the case….then told you tightened em too much. well we came up with something else.
381591038i use this on my test engine. basically these are aeroquip adapters and a signal loop line, the fittings are a part # FBM-2963 1/2-20 flare to -6AN fittings and i am using a -6AN metal braid line that has been pre made. not sure who made the line but they are available through summit racing on-line. you can even buy a short length of line and buy fittings to make the line yourself to whatever length you want. use steel fittings not aluminum for transmission lines. i am a big advocate for use of metal braid line for just about everything on a derby car. hydraulic lines get the job done just as well. i like this set up for a loop line simply because it’s durable and flexible so the tunnel of the car will not kink the steel line. obviously we know the fate of using rubber fuel line and hose clamps. never do that it’s fuel line….use it for fuel and vacuum. as stated in previous posts the fittings on a th350 and th400 are not a pipe thread they are a unique thread pattern from gm. you can get stuff close but to do it right you must use the original fittings w adapters.