my junk yard truck

[phillbus914]

Originally Posted by imadumass

Take it or leave it. By the way, if this post gets deleted, we will all know that this forum is too scared of being politically correct to actually call someone on bad judgement.

Thank you for your time.

I don't think that anyone is saying you're in the wrong to point out a flaw in this setup - if that's the case (I still don't know the correct answer) But when you call people dumb & that they need to clean the turds out of their eyes, you're just plain being an asshole.

Someone would need to make (or find) an animated setup, or drawing with arrows showing which shaft/gear spins what way for me to understand this thing.

By the way what part of this is so life threating? Just wondering.

[Steve]

I think imadumass has a good point and although you have every right to built something get yourself hurt, your passenger may not completely understand the risks of hopping into a custom built vehicle.

After thinking about this I hope that you decide to put more than just some sheet metal between you and those whirling driveshafts that could come flying apart at any time. A heavy rotating mass has tremendous power at drag races it is not uncommon that a flywheel will break free cut its way through a car.

[the_experience03]

Fast spinning steel parts that don't stay there they are supposed to (like chains and sprockets) are the dangerous part.

If I get bored later tonight I will draw something up explaining why it would work to just turn the differential around.

[lapeer20m]

Winter has finally arrived. Temps never climbed out of the 20's yesterday and we have snow.

Took just over 2,200 pounds of scrap off of the truck, including the rear axle, about 12 foot of frame, the cab, ect. Scrap steel is going for $100/ton right now, so that was a nice bonus. She should weigh about 2,000 pounds without passengers now.

Well I didn't get any photos, but last nite we set sail on the trucks maiden voyage....actually we just started her up and drove around the yard for a few minutes. Mostly so i could move her out of my fathers barn and to test our new steel 10 gallon fuel cell.

The project isn't quite finished, but everything works. The rear wheels drive the correct direction, the rear steer works although a little slow. I didn't have any power steering fluid laying around and tried to substitute hydraulic fluid instead....apparently those two materials have different properties at 20 degrees F. With the tires on the drivers side in the air and the slack taken out of the system, i marked the front and rear tires with chalk then spun the rear tire wich in turn spun the front tire so i could check how accurate my gear ratios are. After about 6 revolutions the front and rear tires are still nearly perfectly inline. I'm very happy about that.

Still need to build the rollbar, move the radiator, paint, build a few guards for the spinny parts, add seatbelts, ect ect ect

My passenger is the guy who helped me build the truck. When he chooses to ride in the passenger seat that is an example of informed consent. Driving/riding in the truck isn't a guaranteed death sentence. Beides the increased chance of rollover, what makes this truck so dangerous? iamadumbass, what makes you qualified to be an armchair critique? Between the 2 of us, we have years of schooling and real world expierence when it comes to fabricating, mechanical, electrical, and metal work. We also have nearly 20 years combined fire/ems service which gives us a good perspective on safety.



above is a diagram of two exact axles, each with the yoke pointing opposite directions. On the left is an example of how the axle is oriented in my truck. I think it is easiest to understand if you try to orient yourself looking at each shaft/axle individually. In the photo on the right the yoke is pointed away from you. If you were to orient yourself so the yoke from the axle (in the photo on the right) were pointing toward you it would in fact be spinning conter-clock-wise. IF anyone were to doubt that the tires would in fact spin the opposite direction when the yoke is pointed to the front instead of hte back, take an axle and try it yourself. If you do, please shoot a video and post it for all to see.

[the_experience03]

Let me try one more time....You are both correct, but one method requires chains and sprockets while the other method requires just a driveshaft.

Your right picture is backwards. The wheels should be turning "down." Imagine that is the front of the truck...that is the direction that the pinion and driveshaft would be spinning in order to drive you forward, should forward be in the "down" direction on the diagram. Now flip that picture over to simulate the rear. With the way you have the shaft spinning, it would be driven "up" or in reverse. Fortunately, that is not the direction it would be spinning. It would be spiining the opposite direction, thus driving the wheels "down" again and making it go forward. The front and rear driveshafts spin the same direction as the crankshaft. From the driver's seat, this means the crankshaft, front driveshaft, and rear driveshaft will all be spinning counterclockwise. However, the axles are technically facing each other. This, from ar elative aspect, the front is being spun counterclockwise and the rear is being spun clockwise. Because the rear is backwards and being spun backwards, they kind of cancel out and it goes forwards.

Try this. Face the front differential. The driveshaft going to it will spin counterclockwise if you're facing the pinion. It is driven away from you. Now turn around and face the rear axle. The pinion is again facing you, but this time the shaft is spinning clockwise, thus driving the axle twoards you. If you sit in one place (roughly where the t-case is) and the front axle drives away from you while the rear drives towards you, the truck is going forward.


Try this site out.

http://www.4wheeloffroad.com/brandpa...lanche_part_2/

As you can see, their project vehicle has rear steering. Both axles are regular Dynatrac Pro 60's which are designed as front steering axles. The rear has the differential centered, but this is a matter of tube and axleshaft length, not rotation. A front axle goes in the rear and a rear axle can go in the front...there are no consequences of this.

Here is yet another example. Notice that it says they both use Dynatrac Pro Rock 60 centersections. They are identical differentials because front and rear differentials ARE the same.

http://www.4wheeloffroad.com/project...ild/index.html

Hopefully even if you can't see it (it is confusing to visualize), you will see that there are in fact people who have taken front axles and used them in the rear. You don't run into trouble with the direction that it turns until you flip the axle over, that is turn a low pinion into a high pinion axle. That is why they make reverse rotation gear sets. However, when swapping from front to rear, nothing special is necessary. I'm busy trying to find an animation explaining this better, but alas...it has evaded me thus far.

I do want to point out again...obviously your system works. So would turning that rear section around. You are in fact both correct. One method requires chains and sprockets, the other does not. That is the difference.

[the_experience03]

I found another neat article about a rear steering GP Jeep from WWII.

"A long rod transmits the steering input from front to rear. A standard Spicer 25 front axle was used in back, and the tie rod faced the rear. Rear steering was progressive so that during normal driving it wasn't excessively twitchy. The unit actually still drives well, and yes, it turns on a dime. The downfall of the Ford GP model in general was its unreliable and low-power 112ci converted Ford tractor engine."

A standard Spicer 25 front axle was used in the back. It doesn't use a chain drive or anything else. It just works.

http://www.jpmagazine.com/thehistoryof/5463/

[lapeer20m]

You are right, I am wrong. I was unable to wrap my brain around the concept....but after some research and a lot of thinking about the idea, i agree that a front axle will work just fine on the rear of a vehicle.

Sorry for the excitement i caused.

If i had the correct gear ratio in my rear "axle" i'd be tempted to turn it around. That's only a 1 day project. But with 4.10 gears in the rear and 3.73's in the front, i guess i'll just leave it the way it is.

I took her out for another test run last nite. I spun the rear tires a couple of times just to test my chain and sprocket setup.

ONe problem i do have is the Power steering. My ps pump will not run the front and rear at the same time, so today i'm off to buy a 2nd ps pump.

[the_experience03]

The gear ratio thing is a real problem because I can't think of any sort of a graceful way around that problem either so the chains and sprockets have to stay. Just be sure to make a good scatter shield for them (the ones on the mud racers generally are SFI approved). How are you controlling the rear steer? Is it just a double acting cylinder with a simple two way valve? How do you center that guy? Trial and error? How big is the cylinder you're using? I guess it doesn't surprise me that the power steering pump can run both ends if the cylinder is really big, but those power steering pumps are surprisingly powerful. I've heard as much as 5 gpm at 3000 psi for some truck models!

So so far it works ok, huh? Did you ever get the air shocks set up on the rear? I'm interested in seeing some action shots or videos of the new beast.

[lapeer20m]

i spent most of the morning buying parts....that took a suprising amount of time, mostly because i'm cheap. Couldn't find a new ps pump with a v-belt pully for under $100. Finally went to the junk yard and found one from an old dump truck for $25.

To control the rear steer i'm using a setup from an old chevy dump truck with hydraulic assist steering i had laying around. That leaves me with a cylinder with about 1.5" bore, perhaps smaller and the steering box. I welded the pitman arm so it cannot turn. By applying right or left steering inputs into the gearbox it will extend or retract the steering cylinder. I think i'm gonna "upgrade" to a simple hydraulic valve though. The current setup allows the rear steering to float. They'll straighten out or turn on their own as you drive around. A regular valve would keep the steering in one place until you move the lever. As far as centering goes, i've just been doing it by feel. For those of you who have driven in the snow and locked up your e-brake during a turn just for fun causing the rear of the vehicle to slide around....that's kind of how it feels whith the rear steer. You can really feel the position of hte rear steer without looking at the tires.

Today's project was connecting the radiator which has been moved to behind the drivers seat. Lots more cooling there, and the electric fans will stay out of the water. Water kills electric fans in a hurry!
Another problem is that my current radiator is smaller then required for the 350 chevy motor. Moving the radiator away from the heat of the engine will make cooling more efficient. I also installed an inline aux coolant pump i had laying around to help the coolant move the extra distance.

The truck does some mad crazy brodies (doughnuts) even when barely trying. The turning radius is absolutely crazy.

still have to install the "new" ps pump. The current pump is powering the rear wheels so i don't have any ps for the front...with those 38" swampers steering is difficult. Hope to fix that on monday. I want to take the g/f out tonight, then work 24 hours on sunday.

still haven't gotten around to doing the air shocks...but they'll fit nicely into the the slots where the old shocks used to live. They are connected to the lower control arms.


more to come, including photos.......

[the_experience03]

It sounds like you have a pretty good handle on things so far.

In float mode, can the rear steer drift out of center besides just drifting to center? With your caster backwards, I would imagine it has a tendency to drive out of center rather that towards it. That could make for some interesting avoidance manuevers at speed. I think the idea of using the hydraulic valve is much safer.

Part of your steering issues might just be worn out parts. Have someone watch as you turn the wheels to see if there is anything but lateral movement in the steering linkage. A worn out idler arm, flexing centerlink, etc can take away from steering precision and strength an awful lot. I know I'm still waiting on a straight cut billet pitman arm for my truck from Sky for exactly the same problem. The other advantage of the straigh pitman arm will be that my draglink will stop pretending to be a bump stop on drivers front compression.

[lapeer20m]

ya, the rear steering drifts wherever it wants. Makes driving interesting!

the chain and sprocket setup is working good. in 2wd i can shoot rooster tails and pull brodies with no problems. The only issue i have is reverse. Looks like i need to install another pair of idler sprockets to keep the slack out of the chains while in reverse. The truck goes backwards, but the chains "clunk" as the loose non-aligned chain mates with the sprocket.

It's possible that i could take her out next saturday...but a lot of that depends on temperature. Weather lady is talking about highs in the single digits. I don't see much getting accomplished on the truck if it gets that cold.

[lapeer20m]

i need to start taking photos....

got the new hydraulic valve installed for the rear steer...that works excellent! Still have a difficult time remembering which way to steer. Kind of like a video game, it takes time to get used to the controlls.

Took a half-link out of the chains hoping to make them happier in reverse.

Wasted my time installing another junk power steering pump that didn't work. It's tough to find ps pumps at the junk yard with a v-belt pully.

We spent most of the day working on the roll bar and tube body.

The exhaust (currently we have open headers) is about the last of the major projects we haven't started. I think i'm gonna take her to the local muffler shop and let them take care if it for me. It's likely that we could take her out to the 4x4 park a week from saturday. Duel exhaust would look cool, but i'm too cheap to buy 2 mufflers.

Hopefully it'll get warm enough to paint. It got down in the single digits last nite. That sort of thing has a tendancy to take away ones desire to do much of anything. I think i'm gonna go for old hot rod look.....flat black with red trim.....or more like grave digger...shiny black with bright green trim. not sure.

to be continued.....

[paul iossi]

4x4 park where? I'm on the southside of Detroit and need a new place to wheel since Toledo 4 wheelers lost their property to the county park system. Is this a club park or privately owned etc?

[the_experience03]

I'm still waiting on someone to show up at the Iron Range park. Maybe when it warms up....my truck isn't ready to go anyway. I'm currently toying pretty heavily with the idea of turbocharging. I just really really need to get a good grasp on what I can and can't do with my stock fuel injection. While a standalone kit like the SDS would be cool, I don't have the $1500 LC Engineering wants for the kit and I don't have the patience to set up a Megasquirt.

Get all the kinks ironed out of that truck, get it below 100dB at 3000 RPM, and get it loaded on a trailer to come out this way this summer!

[lapeer20m]

the mounds is a genesee county park near flint. It's only 10 bucks per vehicle to go wheeling. They're closed from may 15 to march 15, but open the rest of the year. I think it's either 200 or 400 acres. There is something for everyone from quads, dirt bikes, stock jeeps, to trucks with 60 inch tractor tires. If you go on the weekend it's easy to get unsuck or get someone to tow you out if need be. During the week there aren't too many vehicles around.

[Steve]

Originally Posted by lapeer20m

They're closed from may 15 to march 15

[Griff]

Ya gotta get as much fun done in April as ya can!

[lapeer20m]

closed from march 15 to may 15 lol

[lapeer20m]

here's the latest pic's.....You really need a good sense of vision when you look at the pic's to see the vehicles potential. She's come a long way, but still has a long ways to go....


The rollcage is pretty much finished, the front fenders were removed and the new front end is boxed in, but still needs the sheet metal, battery holder, ect. I'm half tempted to purchase an optima battery just so i can mount it upside down...but i don't know if i'll spend the $$ or not



here's a shot of one of the rear fenders. They're strong enough you can walk on them. Also added an alluminum tool box that got donated to the project














I really want to finish the body work so we can get her painted. She'll look 1,000 times better with paint.....now to decide what colors...

I'm thinking a bit of a grave digger look...black with bright green flames/trim

the guy helping me with the project...this is a co-project...wants to paint it battleship grey with a white star on the hood....The primer grey would help to hide lots of imperfections, but i think it's too boring..

as you can see from the photos....winter finally arrived here in michigan.

[the_experience03]

Word of warning on the Optima...you can m ount them upside down and you can use them upside down, but you cannot charge them upside down. A total loss electrical system is not exactly ideal for any vehicle short of a race car or light aircraft. Personally, I don't think the Optima is ideal for that truck (and I sell Optimas) given its proposed usage. I'd just get a medium sized Group 78 and put a Battery Tender Junior on it unless you plan on driving the truck a lot. An Optima won't self discharge as fast as a flooded lead acid battery, but a flooded battery with a Battery Tender on it won't discharge at all and we all know that the biggest killers of lead acid batteries of any type is heat, vibration, and resting in a discharged state.

Is that a little oil smoke I see coming out of the engine compartment? What did you end up doing for the exhuast? How about that hose hanging under it in the back view? What the heck is that?

I like the sheetmetal work. It gives it that truggy kind of look. It's still recognizable as a Chevy truck, but certainly not the one you'd find on a lot .