My D-I-Y Class 8 Chevy

scottm

Well-Known Member
Posts
1,864
Reaction
509
This truck was a working prerunner that recieved a nice 4-link upgrade in Jan 05. The owner then started upgrading the front end to match the back, but he gave up and sold it to me in Aug 2005, w/o any front susp. Now after almost 4 years, working every spare minute, it is finally nearly done. Ive been saying I will start a thread on it in show n tell for a while, and just decided its time, because it may never look this good again. I am racing it at the Whiplash Firebird event next weekend, and we know what can happen in short course racing!
 

Attachments

Last edited:

scottm

Well-Known Member
Posts
1,864
Reaction
509
The first pic is what it looked like when I dragged it home. Then I cut everything off and rebuilt the front cage completely. Some of the existing cab cage was retained, but most was redone. Probably 6 months had passed by this point, but I was also working hard designing the front susp on the computer, using Pro/Engineer. I did a lot of experiments too, like tacking up arms out of tubing.
 

Attachments

scottm

Well-Known Member
Posts
1,864
Reaction
509
I got pretty far along with the tube lower arms, then I realized the subframe was in the chassis 3/8" off center. Everyone said don't worry about it, but I really wanted to make sheetmetal arms anyway, so I cut it all off and started over.

Now may be a good time for some background. I make probably 1/5 as much money as the typical v-8 truck racer. So to make this possible, I have to do everything myself, from the welding and fabbing, to building the axle and setting the gears, to rebuilding the power steering. BUT I also have some unusual advantages for a d-i-y truck builder. I have been designing and building industrial machinery for more than 20 years. I work at Cutting Edge mfg in phoenix, a fully equipped laser cutting and cnc machine shop. CEM cuts and forms sheet metal parts for Geiser Bros, Foddrill fab, Jagged Extreme, Revenge, and several others. I have designed about a half dozen lower arms for everyone else, so it was natural to do a set for myself. I think they came out pretty well, and I was a lot more careful putting in the subframe the second time around!
 

Attachments

Last edited:

scottm

Well-Known Member
Posts
1,864
Reaction
509
For steering, I mounted a chevy saginaw 2wd box inside the frame rails, mainly so the steering shaft would clear the shocks. The steering shaft uses only 2 u-joints, from the output of the quickener to the box input. I made a short pitman arm, connected to a swingset thru a short drag link. Pro/E made it easy to optimize bumpsteer, with 1/4" toe out per side at full droop. Goin to bed now, more pics to come.
 

Attachments

Last edited:

D. Freeman

Well-Known Member
Posts
422
Reaction
40
Nice rig my girl has the same box ha ha. Is it a little loose and sloppy? mine is. no really . ha ha ha ha.
 

Mcarlson1

Well-Known Member
Posts
824
Reaction
7
Your truck looks really good bro, the fab work looks pretty b****in as well. Are you going to leave the lower subframe as is or are you going to add more tubing? I ask because im wanting to build a front end like that and and just wondering what is best.

Thanks,
Mike
 

Mark Newhan

Well-Known Member
Posts
4,565
Reaction
2,579
Scott, go have some fun with that baby! Good luck!
 

scottm

Well-Known Member
Posts
1,864
Reaction
509
Your truck looks really good bro, the fab work looks pretty b****in as well. Are you going to leave the lower subframe as is or are you going to add more tubing? I ask because im wanting to build a front end like that and and just wondering what is best.

Thanks,
Mike
Thanks Mike! Yeah, those pics are early in the build. Its going to take a while to get to the newer ones.

These pics below show the upright fab process. They mount the upper uniball vertically for max upper arm rotation, necessary with the short upper arm. I am running ford (dont tell anyone) f-150 4x4 hubs up front. My spindle is a modified version of the f-150 4x snout, but with a much smaller thru-hole for more strength. It has a back flange to keep it in the upright in case the weld breaks, and is welded only on the front as shown, so its replacable. Then you see how I first tried to mount the front bump. Not only did it make the shocks too hard to get out, but it had terrible scrub across the top of the upright. The short upper arm results in too much horizontal upright movement at the top of the stroke.

The last 2 pics were taken months later. They show the bumpstop 'follower arm' or slapper arm method, with a pair of 2 inch Fox bumps that came off the old RG La Victoria truck. You can see how the bumper cone actually rolls around the curve at the top of the upright with no scrub at all. These two pics were taken much later, as you can see the engine is in and wired. I have a thread going in Suspension right now about this method of bump mounting, and how I just made a pair of 2 1/2" kings to replace the foxes shown here.
 

Attachments

ZJARCHER

Well-Known Member
Posts
139
Reaction
10
Let's see that 14b truss/links :)

Looks good man! Should see you out at Firebird!
 

Old School 8

Well-Known Member
Posts
1,129
Reaction
115
I like it.

Ive been waiting to see your pictures.

As a fellow Zonie, we'll have to get together sometime. I was up in Phoenix just last Saturday.
 

scottm

Well-Known Member
Posts
1,864
Reaction
509
Thanks Mike - Yes, lmk when you are in town, or at least I will see you at Snowflake.

Here are a couple pics I bought from Kermit at TME Race Photography of me racing at Firebird last weekend. It was an awesome weekend all around and I am still buzzing from it! The truck worked great, and I didn't have to baby it at all. Just hit every jump as fast as it would go. But for that kind of racing, it needs more power, lower gears, and mud terrains.

I will figure out where I left off on the truck build and put up some more pics tonight.
 

Attachments

TauMau

Well-Known Member
Posts
998
Reaction
32
I love your build. You did a fantastic job on it but you don't need me to tell you. I'd love to see what you could do with a buggy concept.
 

Dezertpilot

Well-Known Member
Posts
5,664
Reaction
440
That is one BA Chebby!!! I really like it, especially since you did everything your self!
 

scottm

Well-Known Member
Posts
1,864
Reaction
509
Thanks guys, I really appreciate that. When I started this truck (and on rdc) I didn't know a subframe from a 3-link. I made countless annoying posts and ticked off some of the vip's of offroad. Thanks to everyone who helped and put up over the years. And to the class 8 driver who predicted I would never amount to anything, I am happy to disappoint you!
 

scottm

Well-Known Member
Posts
1,864
Reaction
509
Ok back to the truck. Remember the old saying about race parts? The three desired caracteristics are strong, light, and cheap, but you can only have two of the three! The axle I used was a key part of this project, but it had to be cheap. By conventional wisdom, a class 8 needs about as much of an axle as a tt, meaning a $10-15K Tubeworks or Chrisman. That just wasn't possible on my budget. When my truck came up for sale, I happened to be reading up on the chevy 14 bolt full-floater on Pirate 4x4. They have great articles on modifying for ground clearance, adding disc brakes, setting up gears, etc. They are convinced the 14bff is the best passenger truck axle ever. Another argument in favor came from my good friend Steven Arlia, of Arizona Precision Fab. Steven got me into this mess, and has mentored me through it the whole way. Steven also built Nick Vanderwey's class 8 chevy, one of the winningest trucks in the history of Score and Baja. Guess what? They ran a 14bff for 2 1/2 SEASONS of full-on Score class 8 racing, and never even broke an axle shaft. They did have some problems though, and finally upgraded after hitting a rock and bending up a snout. I was convinced the 14bff was plenty good enough for my whiplash beater, so I went out and bought a few off of craigslist, and never paid more than $100 for one.

This first pic shows an as-purchased $100 CL special hanging from a calibrated load cell. The 'before' weight is a porky 405 pounds, and it has the small 3/4 ton brake drums! The second shows a bare housing, stripped of about 10 pounds of brackets and iron, and modified for 1 inch extra ground clearance. The 3rd shows it with sheetmetal trusses tacked on, ready for welding. Look close and you can see a precision ground aluminum rod clamped into the carrier bearing saddles and sticking out the snouts. This let me know where the housing was distorting from welding. It worked great! I pre-heated the whole thing to 300° F, then welded from the middle out, and alternated sides to keep the giude rod centerd in the snouts. In fact it was straighter after welding than before!
 

Attachments

scottm

Well-Known Member
Posts
1,864
Reaction
509
Almost forgot the hubs... I scored an awesome deal on a bunch of new and used 37x17 bfg projects and 5 on 5 1/2 wheels, so the rear hubs had to be converted. This was one of the hardest parts of the whole truck project, and I probably wont do it again. It would be easier to carve some out from billet. Im missing some pictures and this one is all I could find. I machined the nose down to 4.23 diameter, and turned the back of the hub flat. Then drilled and tapped the original bolt holes for 3/4 inch fine thread, and welded short pieces of allthread into the tapped holes with Ni-99 tig rod. Then resurfaced the front and back of the hubs again. I used a lasered template to pilot-drill the new bolt pattern, then enlarged to the shoulder dia of a Moroso 5/8-18 stud. The 5 on 5.5 pattern will partially hit 2 of the plugged holes, requiring you to drill through welded cast iron. Found out its only possible with a $50 carbide drill...
 

Attachments

scottm

Well-Known Member
Posts
1,864
Reaction
509
After all the welding was done, it was time to put in the gear set. I learned from Pirate 4x that the 14bff is probably the easiest axle of all to install gears. I went by a pirate tech article, which was much better than the instructions that came with my new gears. All you need is a dial indicator as shown, and sure enough, perfect gear contact! I dont have a good pic of it complete, but with Coleman 13 inch rotors and 4 piston calipers, the ready to run weight was 360 pounds.
 

Attachments

Lance T

Well-Known Member
Posts
1,312
Reaction
57
Very nice! I impressed by your budget building skills. Bring it up to a SNORE race so we can see it in action!
 

14802

Well-Known Member
Posts
575
Reaction
22
Good looking rearend you got there.:) Know were I can find one? Looks like all those hours of hard work paid off. Thanks for sharing the build pictures.
 
Top