Sharp Motorsports 4600 Class Early Bronco

[arse_sidewards]

-cough- Matt Peterson's WJ -cough-

What's the backstory?

 

['84 Bronco II]

This showed up last week

Awesome, thanks for the support!

What's the backstory?

It was way before I decided to build a car, so don't take it as me griping personally, but he had tube bolted in where the doors should have been and the rules explicitly state that you must retain some type of door that opens and closes. He was the first two-time KOH 4600 winner, but despite other competitors protesting and being a clear rule violation, they never made him do anything about it.

 

[Pitbullcruiser]

Updates?

 

['84 Bronco II]

Updates?

Unfortunately not too much. I've been out of the house the last 3 weekends and been waiting on some parts to show up. I have been trying to get gears and upgrade parts for my Dana 20 from Jack O'Brien, but it's like the guy is allergic to money or something If it doesn't work out with him, I am not sure what I am going to do for a transfer case since I need better gearing than a stock Dana 20 provides and an Atlas won't clock above the bottom of the frame rails (not to mention they are $$$). I suppose I could still go the NWF integrated doubler route, but first gear would be stupid low in double low for an automatic (104:1). I would also worry about the strength of a stock Dana 20 gear set behind a doubler (Jack O'Brien claims his gears are ~50% stronger than stock). Both the atlas and doubler route would be heavier than an upgraded Dana 20; the Atlas has 40 Lbs. on a Dana 20, and I am not sure how much weight the doubler would add.

I finally bought my link material for the 3 link. After much deliberation I decided to go with 2.5" OD 1/4" wall DOM lowers since everyone bends 2"OD 1/4" wall DOM. I could have gone with heavier wall tubing such as 2.125" or 2.25" OD with the same 1.5" ID, but the 2.5" OD 1/4" wall was stronger, lighter and cheaper; although, I had to buy some new tubing bungs which ate up all the cost savings. I also considered heat treated 4130 and 7075-T6, but they were way more expensive and I was concerned about running aluminum links since aluminum "sticks" to the rocks worse than steel, and I am going to be doing a lot of sliding over rocks on 35" tires.

Here's a table I used to make my decision based on numbers generated from the Link calculator and prices from Midwest Steel and Aluminum and Bent Fab AZ:

Material​	Size​	Weight (~40")​	FOS Bending​	Cost (40")​
DOM​	2"x.25"​	14.3 Lbs​	1.3​	$53.83​
DOM​	2.125"x.3125"​	18.5 Lbs​	1.72​	$92.91​
DOM​	2.25"x.375"​	23.0 Lbs​	2.18​	$89.18​
DOM​	2.5"x.25"​	18.4 Lbs​	2.2​	$69.75​
4130 Heat Treated​	2"x.25"​	14.3 Lbs​	2.67​	$265.00​
7075-T6​	2" Solid​	11.7 Lbs​	2.6​	$180.20​

Here's the obligatory beer can comparison between a beer can and 1.25" rod ends with both 1.5" and 2" ID tubing bungs:

The 2" ID tubing bungs are from Rockwell Offroad since they had the best pricing I could find and hex ends. The nice thing about jumping to 2" ID bungs is that there is a lot more meat in the threaded area, so you don't have to worry as much about warping the threads when you burn them in.

I also made a material rack for my tubing so I could stop tripping over it

I finally managed to score a set of decent used tires for my race spares since I don't have a baller tire sponsor that sends my free tires It took me almost six months to find some tires that weren't roached with the seller asking for 75% of new price

 

[ChrisRWG]

Good call on going with the bigger tubing! Other than not being able to get it to clock flat, the atlas would be my choice. I have messed around with strengthening Dana 300s and like 5 different doublers/crawl boxes and I like the atlas much better. It really is a buy once cry once type of purchase.

 

['84 Bronco II]

Good call on going with the bigger tubing! Other than not being able to get it to clock flat, the atlas would be my choice. I have messed around with strengthening Dana 300s and like 5 different doublers/crawl boxes and I like the atlas much better. It really is a buy once cry once type of purchase.

Yeah, I am just not very impressed with their shifting, and between the extra weight and having it hang down, I am not sure I want to go that route. We'll see. I really want to keep a flat belly so I can stay low and still be able to slide over stuff.

 

[Pitbullcruiser]

Nice! I also have Craigslist race spares lol.

 

['84 Bronco II]

Nice! I also have Craigslist race spares lol.

Glad I am not the only one

 

[Maquet24]

Hey! Stop galavanting around with your rockcrawler on social media and get some work done on this!!!

 

['84 Bronco II]

Hey! Stop galavanting around with your rockcrawler on social media and get some work done on this!!!

Frankly I am ashamed how little progress has been being made lately. I have been trying to work on it for at least an hour a day this last week.

Here are the updates: Right now I am pulling the C4 out of the '75 to run in the race Bronco, I have given up on trying to get gears for the Dana 20 from Jack O'Brien after 4 months of emails and phone calls trying to buy parts he supposedly had in stock , and I still haven't seen a '99-'08 Dana 60U in the junkyard. I have been focusing lately on trying to sell off and scrap parts that I won't be reusing so I can get some space back in the shop to actually work in.

I am thinking I am going to get one of the integrated doublers from Northwest Fab since my overall drivetrain length will only change by about an inch, it's cheaper than an atlas, and I'll be able to clock the Dana 20 hopefully up above the bottom of the frame. 1st gear in double low will be useless, but I think I'll be running with the doubler in high range 99% of the time.

I did find a couple of drum brake Dana 60Us in the junkyard (a '95 and a '98) and I may just grab one and convert to disc brakes, but an aftermarket disc brake conversion will conversion will cost roughly 3X what a disc brake Dana 60U would cost from the yard if one would ever show up

 

[Maquet24]

I'm a big Atlas II fan. I've definetly gone with other options in the past to just inevitably bite the bullet and get the Atlas. each time it cost me extra money and time to not just get the atlas up front. Buy once cry once...

 

['84 Bronco II]

I'm a big Atlas II fan. I've definetly gone with other options in the past to just inevitably bite the bullet and get the Atlas. each time it cost me extra money and time to not just get the atlas up front. Buy once cry once...

My main reservation is how low they hang in an early Bronco chassis since I can't modify the frame and I am only on 35" tires. You'll probably get to say "I told you so!"

 

[fordpickupman]

Great build. I’m excited to see where this goes.

 

['84 Bronco II]

I figure I should add in a few pictures I haven't posted previously just so people know that this build still has a pulse

I used a propane weed burner to preheat the axle housing to ~600ºF prior to welding and ran some .035" ER70S-6 in my Millermatic 211 cranked to kill. I did some post heat after welding prior to wrapping the housing in blankets and it seems to have worked out; no cracks or warpage

Not the prettiest welds since I was rushing to get it all welded up before the housing lost too much heat.

Looks like a body

Stealing the C4 out of the '75

 

[fordpickupman]

I like how you preheated the axle

 

[ChrisRWG]

It's been over a month since the last update and KOH 2022 is fast approaching! Where's the updates lol

 

['84 Bronco II]

It's been over a month since the last update and KOH 2022 is fast approaching! Where's the updates lol

Tell me about it, I am definitely feeling the pressure. I haven't had much help from all the people who said they wanted to be a part of the race effort That said, I know you expressed some interest, so if you want to be a part of the team and help get some work done, I'll take any help I can get. Free beer for anyone that shows up to help


I have my C4 with the guys over at Dynamic Race Trans right now getting their "Competition Plus" build which includes a hardened input shaft, partial rollerzation, and a forward manual valve body. I also had them add their C4 low gear set to the build which convert 1st and 2nd gear to 2.90 and 1.60 from 2.46 and 1.46 respectively. They claim this build should be good with over 500 HP and is what they recommended for my use even though I'll probably only be around 350 HP at the flywheel for the first race season, and maybe closer to 450 HP in the future.

I also ended up ordering an Atlas 3.0 ratio transfer case after all after wasting way too much time trying to do business with Jack O'brien to build the Dana 20 Jack O'brien finally gave me the price on the gears after literal months of back and forth ($2,217.32 for just the gears for those wondering), and with the cost of a twin stick kit, modified shift rails, and a 32 spline rear output, it would cost considerably more to build out the Dana 20 than just buying an Atlas Not to mention, there is no 32 spline front output shaft available for the Dana 20, and the factory 26 spline front output shaft from full-size Dana 20 applications are impossible to find now. Unfortunately, the lead time over at Advanced Adapters for an Atlas is currently at 20 weeks It is going to be cutting it close to KOH, so I am going to build with the Dana 20 for now and hopefully have time to swap it in before I need to head out for the lake bed. The crawl ratio is going to suck at 38:1 if I end up having to run with the Dana 20

I am going to start working on the engine next, but I need to make some room since all three of my engine stands are occupied at the moment. The plan is go .030"over and stroke it out to 347ci and run about 10:1 compression. I've got an Explorer top end (GT40P heads and GT40 intake), accessory setup, and coil-on-plug ignition system. I am thinking I am going to run a Comp XE264HR cam which has .512"lift on the intake and exhaust and 212/218 intake/exhaust duration at .050" since the GT40P heads don't have any additional flow above .500"lift and I want to maintain strong low and mid RPM torque and don't plan on revving it out past 6,000RPM. I also want to be able to run as low of a torque converter stall as I can get away with to avoid having to battle high tranny temps. If anyone thinks I am way off base with the cam selection, or has a recommendation for a better cam for my application, I am all ears!

I still haven't had luck finding a disc brake Dana 60U for the rear and have been kicking myself for not grabbing one of the drum brake versions I came across earlier. At this point, I can't keep waiting much longer, so I am going to grab the next Dana 60U that shows up at the yard regardless of the brakes it has and I'll just spend the $350-$400 for a brake conversion if I need to.


I wish I had more to update, but I have had to many things going on lately and haven't had the time I need to focus on this thing and make some serious progress (I am going to be out of town this weekend too ).

 

[arse_sidewards]

I still haven't had luck finding a disc brake Dana 60U for the rear and have been kicking myself for not grabbing one of the drum brake versions I came across earlier. At this point, I can't keep waiting much longer, so I am going to grab the next Dana 60U that shows up at the yard regardless of the brakes it has and I'll just spend the $350-$400 for a brake conversion if I need to.

Get on CL and find someone parting out an E350 or hit up car-part. You shouldn't spend more than $200.

 

['84 Bronco II]

Get on CL and find someone parting out an E350 or hit up car-part. You shouldn't spend more than $200.

I've been watching Craigslist and haven't seen anything, and all the listings I have seen on CarPart were $500-$1000, and I never got a response from one of the yards I did try to contact. You would think 13+ year old Ford vans would be cheap and plentiful

 

[rattle_snake]

That cam is appropriate for your use. I used a very similar crane (but with more lift) on a 347 w/ TFS heads. Good torque off converter to 5500. It replaced a cam that had 220 intake and that one sucked on low end and had no vacuum for brakes. 8* less duration made a huge difference in off road usability and manners.

 

[welndmn]

That's a bummer, we have the Disc 60u up here in San Francisco bay area, but shipping it might be a PITA.
With the atlas, I'm sure you're already planning on it, but they fit if you offset the motor all the way with no frame mods.
It just means you will also have your exhaust outside the frame on the passenger side.

 

['84 Bronco II]

That's a bummer, we have the Disc 60u up here in San Francisco bay area, but shipping it might be a PITA.
With the atlas, I'm sure you're already planning on it, but they fit if you offset the motor all the way with no frame mods.
It just means you will also have your exhaust outside the frame on the passenger side.

You're right, shipping probably would make it not worth it

Do you have any pictures or more information on offsetting the drivetrain? I am not sure whether it will be feasible for me since I need room for the upper link on the passenger side and there probably wouldn't be any. I am not wild about running the exhaust outside the frame, but is there room without cutting the inner fender (illegal in 4600)? I was toying with the idea of running 1"of body lift (maximum allowed in the class) just to be able to get my shock mounts that much higher anyway, so perhaps that would give me clearance to route the exhaust.

That cam is appropriate for your use. I used a very similar crane (but with more lift) on a 347 w/ TFS heads. Good torque off converter to 5500. It replaced a cam that had 220 intake and that one sucked on low end and had no vacuum for brakes. 8* less duration made a huge difference in off road usability and manners.

Thanks for the confirmation. I am not really worried about vacuum since I will be running manual brakes, but I don't have a lot of experience building engines. Most of what I know comes from reading forums and watching Engine Masters and Richard Holdener videos

 

[welndmn]

There were not be any room on the passenger side for an upper link, you'd have to put on on the drivers side or run a radius arm.
I'd 100% put the body lift on it, you will need the room everywhere that gives you, Broncos are so tight.

 

['84 Bronco II]

I didn't post any pictures in my last update, so I figured I would go ahead and add them in this post.

Here is how I crated the tranny to send it across the country. I built it out of 7/16" plywood and 1/4" veneer around the outside with some 2x4s for cribbing. I filled some trash bags with expanding insulation foam and packed them around the tranny. All together it was 24" wide, 15.5" deep, and 19.25" tall and weighed 106 Lbs in case anyone else needs to quote a C4 for shipping

After sending off the tranny, I cleaned up the bell housing which was pretty disgusting. Unfortunately, once it was clean I could see the big cracks around a couple of the mounting holes where it bolts to the tranny Fortunately Dynamic was able to supply me with a good 6.25" deep take-off bell housing for a 164 tooth flywheel.

Dynamic shipped the tranny back on Monday, so I should be getting it very soon. This week a miracle happened and a 2007 E350 with the full-floating, disc brake Dana 60U showed up at the local yard. I pulled it after work the next day

I also got in the majority of the engine parts this week. I ordered up a balanced 347 rotating assembly from Skip White Performance with the 10cc dished pistons which should put me around 10:1 static compression with the GT40P heads depending on the head gaskets I use. Speaking of head gaskets, I've got some standard head gaskets with the Felpro complete engine gasket set I ordered, but I am thinking about springing for a set of MLS head gaskets. I am not sure if they are worth it for a relatively mild engine build like mine though, so I am open to input from people smarter than me. I will probably be upgrading to aluminum heads after the first year of racing or so, so maybe sticking with the standard head gaskets for now is alright. Other goodies include the Comp XE264HR cam I mentioned earlier as well as ARP head studs and main bearing studs.

 

['84 Bronco II]

Long time no post

I have been putting off making this post, but I came to the realization a couple of months ago that there is no way I will be making KOH 2022 with the Bronco

My project management has been piss-poor to be honest (ironically my wife is finishing up her MBA in project management ). I completely failed to identify long lead items, and as many of you know, current supplier lead times are insane. I have ordered almost all of the major components at this point, but my shocks for instance are still 6+ months out and I am still waiting on my Atlas to name a few hangups. I still have tons of smaller items I will need to order as the build progresses. I identified and priced out major components and safety items I would need at the beginning of the build, but I consistently blew way over my estimates with the parts I actually ended up purchasing. My original intention was a build that had a reasonable chance of being able to finish, but I have ended up trying to build a rig that will be competitive. I am still going to continue on with the build and hopefully it will be ready in time to catch a Western Series race or two next year. In a sense, it is a bit of a relief not to have KOH as the debut race due to the logistics involved and how much I still need to learn.

I will be pitting for Pitbullcruiser, the Team Trail Rig Racing 4653 Toyota, and I am hoping to learn a lot from that to be better prepared for KOH 2023.


In other news, I got my 32 gallon Jaz fuel cell in, the C4 back from Dynamic, and my leaf springs from Alcan.

The leaf packs from Alcan are 58" with a centered pin. They are basically 5" longer front and rear than a stock Bronco pack and arched for 4" of lift (obviously this depends on how I set up my perches). They are also 2.5" wide compared to 2.25" for factory Bronco packs, and are an 8 leaf design with a half leaf on top to help control axle wrap. They have Alcan's "orbit eyes" at the back which should help the bushings and springs themselves live longer while providing more articulation.

 

[cagcig]

How many years is it going to take to build this thing? KOH 2023 is just around the corner, get to work.

 

['84 Bronco II]

How many years is it going to take to build this thing? KOH 2023 is just around the corner, get to work.

Tell me about it

Still slowly collecting parts. I just got my shocks in last month that I ordered from King in November of last year I've got almost all of the suspension and drivetrain parts now, and I just bought a Rogue Fab tubing bender so I can start working on bending tube. This has been on the back burner for too long, I am hoping to get back to hitting it hard soon.

 

[Pickuptrucker]

Cool build! It will be awesome to see some more progress!

 

[wvracer821]

any updates?

 

['84 Bronco II]

any updates?

Thanks for putting me on the spot

This is still happening, but to be honest, I lost my momentum and motivation with all the part delays I was dealing with. I am planning on getting back on it now that the weather should be warming up soon and am hoping to have it at the next Hammers. I have most of the big items, I just need to start putting it all together.