Dirt Late Model Stock car.

[Mooneyzs]

Wow... this build is looking great. You are doing a killer job. the frame looks great as well as the front end. You have made some great progress since I last saw this build. Keep up the great work.

[BigDaddy]

Glad I could help Ken !! Your build is shaping up nicely !! That larger scale is definitely good to get all the details in there.

On your 5th Coil/Torque Arm set up...........looks dead on ! However, the torque arm and the 5th coil really only control "axle wrap". They can also help to apply dynamic weight transfer back to the rear axle to aid in planting the rear end. Under acceleration, the rear end will start to wrap or twist along the axle line, and could pull the drive shaft right out of the back of the transmission. A torque arm is there to help with that. Along with that shock or spring rod, which is why it's called a "5th coil", there is sometimes a length of chain between the frame bar directly above the torque arm, and the arm itself. That change keeps the arm from over extending that 5th coil. Alot of the cars will use lengths of chain or stout cables attached to the rear axle, and the frame directly above the axle to keep the axle from over extending the shocks. That would also do what's called "over index the birdcages". Meaning the birdcage would twist so far around the axle, that it would bind up to the point of no longer moving thru it's arc. On an "underslung chassis" which is a chassis with framework under the axle, there is no need for chains or lengths of cable. However, on a chassis with no underslung framework, such as MasterSbilt, you will need to have lengths of chain or cable.

Rear steer is controlled by the 4 link set up. Depending on how the car is set up, the links on the left rear will literally pull the left rear tire forward by a few inches to lessen the wheel base on the left side of the car. Creating stagger, so to speak. With a shorter wheel base on the left side, the car will naturally want to track to the left. Or steer to the left. Each chassis manufacturer has it's own baseline set ups for their cars, and then they will fine tune from there. The 4 links are rarely, if ever parallel. Under hard acceleration, such as coming off the corner, the car can be seen all "hiked up", and that left rear is jacked way up in the air. You can see the left rear tire practically rubbing on the back of the cockpit. This is the rear steer at work. When the car is all hiked up, it's called "up on the bars". When entering the corner, the driver will set the car by hitting the brake quickly, or letting off the gas. You can see the car drop down to normal ride height, and the driver will begin driving thru the corner. Once he gets back on the gas, the car will start to raise up on that left rear as the weight is transferred over to the right side of the car. It's called "side bite". Then the driver mashes the gas hard off the corner and the car is all the way up on the bars. This is where the lengths of cable or chain keep the rear end from going too far. At this point, the bars will be nearly vertical as the chassis lifts from the power being transferred. Again, the 5th Coil helps with this.

All of these things work together, in unison to get the most traction as possible, thus making the car as fast as possible.

The birdcages, are the aluminum blocks that the shocks, and the 4 links are attached to. They rotate around the axle so the axle can move thru it's suspension arc. The literally "float" on the axle. They dont move side to side, but will rotate around the axle. They are just mounts for the shocks and 4 links.

Another item to add to your build is the "J-bar". This acts like a panhard rod on the rear end. It's called a "J-bar" because it's shaped like a "J". The curve, wraps around the pinion of the rear end, where the drive shaft mounts its u-joint. The other end, the straight end, will mount at a point on the chassis on the left side of the car. This "J-bar" will be parallel with the rear axle. However, the "J-bar" itself is never parallel with the ground. Just like a panhard rod...or in Nascar circles, a "track bar".........it controls the roll center of the rear end. It's mounted to a plate that mounts to the pinion on the rear end center section. It will have a few holes for adjustment in it. Whereas the frame mount of the J-bar will have several vertical holes for adjustment.

Wow........I rambled on and on !!! Sorry for the "suspension lessons", but these cars have become very technilogically advanced, and it kind of facinates me on how it all works together.

At any rate, I will be following along with your build as it has captured my interest !!!!

Great work so far, keep it up !!!!

[Old Sprinter]

Yes Sir; you're a race car suspenion junkie like me, Joe. I get it (after reading a bunch about it) on how the rear steer works. I used to watch these cars on TV and wonder " how do they do that" The cars I've been around, all my life, are so simple compared to these. Upper radius rod and lower torsion bar arm connected to a birdcage which rotates around a live axle. All held in place latterally by a Jacobs Ladder at the rear and a straight axle with one radius rod on the left and two on the right and a panard bar in the front. Easy stuff that's been around for ever. I see that, on these Late Models, placement of the radius rods is so different because you're asking it to do something slightly different than say a midget or sprinter. This arrangement took some real thinking to get to where it is today. I used to not pay much attention to these Taxi Cabs, as I called them, but now they are becoming one of my favorites. I know I have more to add to the rear such as the J bar and chain and control bar to the 5th link as well as coilovers. I started the big block motor today and have one question. The driver's cockpit is totally enclosed from the motor, etc. so how does does he shift gears? Does the shifter stick thru the sheet metal or does it jog over and encase the transmission as well. I can't find any reference material that shows this arrangement. Once again a sprinter doesn't shift, it just has a slider or in and out box to engage or disengage the motor to the rear end. Thanks for the encouragement and all the information.

Edited January 23, 2012 by Old Sprinter

[BigDaddy]

Hey Ken........yeah, it's kinda strange that a Sprint Car or Midget is so "simple" compared to a Late Model. One must wonder, why ??!! Why couldnt the Late Model be that simple !!

As far as the shifter, yes, it is a simple two handle shifter that literally sticks up thru the tunnel. Since the Late Model isnt an "open cockpit" type of car such as a Cup car, or a simple Hobby Stock.......the "wall" dividing the rest of the "passenger" area is used as a sort of fire wall. And there is a simple "shelf" or tunnel built into that wall. The shifter assembly passes up thru this "shelf" and the driver will shift just like a normal car.

However, the transmission is completely different than a standard transmission in a street car. The clutch in a dirt late model works just the opposite !! Rather than let the clutch out to move the car forward....in a late model, you press the clutch in to get the car to move forward. Start out in first gear, push the clutch in, hold it in as you pull away. Get up some speed, and rpm, then just yank it back into 2nd or High gear and left off the clutch. And you're racin !! It's an internal clutch transmission and only 2 speeds forward. Reverse is the same way as pulling away in first gear. Push the clutch in, and you go backwards.

The shifter rods look very much like, say a Muncie 4 speed. Two simple aluminum tubes with rod ends/heim joints, that attach to the shift levers on the transmission. You will probably have to scratchbuild a Bert or Brinn transmission as they look very different than a Muncie or Powerglide. Same type of bellhousing as a Muncie, but the trans itself is very different.

I'll attach some photos here that I was able to find.............

In the photo above, you can see the shifters on the right side, sticking out of the "tunnel". Straight ahead is the clutch/brake pedal assembly, with the master cylinders above. The bracket sticking straight out above the pedals is the steering shaft mount. A rod end/heim joint will be used here to pass the steering shaft thru and mount the quick change steering wheel to. This photo is taken from the back of the cockpit. Where the seat would normally mount.

This photo shows a Brinn transmission. The two levers at the side of the trans is the shift levers, that the shifter assembly shown below will attach to. The shifter handles is what is shown above, on the right side of the photo. These are made of aluminum, and most of the time anodized, either purple, gold, red and sometimes black.

Hopefully, this helps !! The transmission simply bolts to the bellhousing and "hangs off" the back of the motor. There is sometimes a mounting point under the tailhousing of the trans. Alot of time time, there is no mount so the trans can flex with the chassis. The cockpit is the only part that is separated from the underside of the car. Otherwise, the rear end, trans and all the suspension as well as the drive shaft are only encased, by the body panels. They sort of just sit there in the open....so to speak, but under the body. There are no belly pans on these cars. The only panel under the car is sometimes a 1/4 inch thick aluminum sheet under the driver compartment. To keep things coming thru the floor of the cockpit. Otherwise, it's open to the elements under there.

Also, a Late Model doesnt use that rear end disengaging shifter that a Sprint Car uses. Since it uses a transmission. The rear end is always engaged to the trans. Placing the trans in neutral, obviously, allows it to be started standing still. No push trucks in late model racing !!!!

Keep up the good work !!!

[road_warrior05]

Spot on description Joe

[Old Sprinter]

Huge help, Joe, thanks. I think I got it. I found dimensions for the Brinn transmission. I guess the reason a Late Model can't be as simple as a sprinter is the longer wheel base and track, plus the extra wieght. There is a lot of unsprung wieght, though, in the rear suspension of a Late Model, don't you think?

[BigDaddy]

Yeah, there is some unsprung weight there. However not much more than a Sprint Car. Hubs, axle tubes and larger birdcages, of course. The weight of a Sprint Car gives it that power to weight ratio advantage.

Late Models can be as light as around 2200 lbs, whereas a Sprint Car has gotten down to about 1250 ? Forgive me, as the we only have one Sprint track around these parts, and they're 360 cars. So, Im not so much up on the specs as I am for Late Models.

Our Late Models here, are weekly rules cars with 360 ci limit, on a 4 bbl 850 carb. They also have a 8500 chip rule. We also have a "Limited Late Model" which started out as a iron motor on a Holley 4412 2 bbl carb flowing 500 cfm. But, they have graduated to the GM 602 and GM 604 crate engines, running Holley 4 bbls. On a big 4/10ths mile, like I-80 Speedway where I work, it's kinda like watching paint dry !! But, there are also tour Late Models that swing thru here, and they're open cars. Big inch motors on big carbs, no chip rule, and they're at the 2200 lb range. Those cars put on a good show as they're practically wide open all the way around.

When the ASCS cars come to town, they ARE wide open all the way around. And they flat haul the mail !!! Brian Brown practically owns the place as he's won every race he's ever entered there, but one !! We've had some non-wing shows as well, the big 410 cars. THAT is some crazy stuff there !!! Dave Darland, Levi Jones, Robert Ballou, Cory Kruseman, et al......put on probably the best Sprint show that was ever at that track. Slide jobs, wheel stands, etc etc.

Interesting story.........when I used to work the pits as the "pit reporter".....we had a TNT non-wing show. Damian Gardner, former winner at the Chili Bowl, was running his car that nite. He had a fuel pump come apart and his car caught fire. Although, none of us knew it till he came to a stop on the front stretch right in front of me ! Only then did a few of us see the methanol fumes that were burning his legs. Which are sure not easy to see !! He climbed out of the car and bailed over the top of the cage with his legs on fire. I guess I just reacted and jumped down off the front stretch wall, and did the best I could to put the fire out. I think I fell off that wall, more so than jumped, but it was an adrenaline thing and I wasnt going to watch that kid burn in front of me and the entire grandstand. I did the best I could to beat down the flames, but it just wasnt going out. I burnt the hair off of my arms and backs of my hands, and scared the living you know what outta me !! It felt like an eternity for the fire crew to get there, and finally, Jack Dover's dad, Marc, jumped off the wall, and used his shirt to help snuff the fire. We got it out, and then, did we realize the car was still burning !!!! If that thing had gone up, all three of us wouldve been french fries right there. The car was only 10 feet from us. Keep in mind that rest of the field handnt yet come to a stop for the red flag. So, we're down on the track with a bunch of cars whizzin' by us at full tilt !!! Finally, they got the field stopped, and the fire crew got there to assess his injuries. THEN, the race director, who's a former racer and a good friend of mine, took me aside and asked to see my hands. In all that action and confusion, I was so amped up on adrenaline, that I didnt even think about that. I was still in a bit of shock and just stared at him and put my hands up, and he said "turn them over". I thought, "oh geeeezzzz, my hands are hamburger right now". I turned them over and he just said "good, you're ok". I looked down and they were a little red, and a little blackened, but no damage !!! Gardner had some 1st degree burns on his feet and lower legs, but he walked away and they took him to the hospital for treatment and he was racing a few days later.

That was a scary deal, for sure !!! Hope I never have to see that kinda thing again, but if I do, I hope I can react the same way. Just couldnt let that kid burn up like that.

Didnt mean to hijack the thread !!

We now return you to regular scheduled programming................

[Old Sprinter]

Good story, Joe and nice job reacting to the sitution. Fire has always scared me when I raced those things. I have been burned a few times but nothing serious. Open driveline got me once ( in a supermodified) and that one I still have the scares from. I like the 410 non wing cars the best. The CRA and USAC run those here, sometimes, but mainly the 360s which still put on a great show. This year I'm going to more Late Model shows for sure. They run those Open Comp Late Models here (3/8 mile track) as well as the crate motor cars and they do haul. Fun stuff. I have never driven a stock car before but it's got to be a blast trying to get that beast through traffic and be smooth. Joe I really enjoy your posts and I'm sure the rest do to, so keep it up. Thanks. Ken

[Old Sprinter]

Okay back to model building, if I had the money it would be real. So I have got the motor far enough along to set it in the chassis. Big block Chevy with a million or so cubic inches.LOL

[BigDaddy]

Looks great Ken !!! However, big blocks arent used in Late Models. Too heavy. Small Blocks, bored out to upwards of 430 ci are common for Open Late Models. Weekly-rules style Late Models will max out at around 364 ci. 406, 415, 418....etc. are just a few of the common displacements in the Open rules. But, they're all Small Blocks, be it Chevrolet, Ford, or Mopar.

Now, back in the 70's, Late Models were using Big Blocks, because they were stump pullers, and the tracks were always heavy, and muddy in those days. A track like that, back then, would blow the bottom end out of a Small Block !!

As you know, tracks nowadays, are all dry slick.

Of course, this is YOUR model, so really, you could have a SuperCharged Hemi Detroit Diesel in there if ya wanted to !!!

[Old Sprinter]

Joe; I know the ones that run here on a regular basis are all small blocks, however I went to an Open Comp show about maybe 5 years ago and they were mostly big blocks. It was a traveling tour show. It was the first time I have really watched a whole night of these kind of cars racing. Also it was a banked 3/8 mile track and man they put on a show. This was in Nevada, by Reno. Anyway you have busted my bubble. LOL. I am going to keep it the way it is and most folks won't even know the difference and I will not tell them. I have always thought that a stump pulling diesel motor would be the ticket on a heavy track. You're right though, everywhere you go it's dry/slick certainly by main event time. When clay has the moister well embeded and is sticky, not muddy you can drive a car as fast or maybe a hair faster than if you were racing on asphalt, or so it seems. It takes much greater skill to race on dry/slick as you know. But I'd rather qualify on the tacky surface. Thanks, as always, for your help.I look forward to your post. Ken

[MadKaw6]

Nice work!

[Romell R]

Man there are some amazing builders on this site and Ken my friend you are one of them! This build is just OUTSTANDING! keep up the excellent work and keep the photos comming.

[Old Sprinter]

Thank you both." After Further Review" ( as they say in the NFL) I'm building a small block Chevy for this Late Model so I should have some new photos by mid week. Ken

[James2]

Outstanding build and WIP. Thank you for sharing. I can only guess at how many guys are buying Evergreen rod right know!

[BKcustoms]

I can only guess at how many guys are buying Evergreen rod right know!

. Lol! I just bought some the other day to build a 1:24 late model after seeing this.

[Old Sprinter]

. Lol! I just bought some the other day to build a 1:24 late model after seeing this.

Billy: you may already know this but if not, there are full size 1/24 scale blueprints on Dirtmodelers web site that you can print up and they're free. That's what I used only I made it 3 times bigger to 1/8 scale. It will get you through building the frame atleast. They are pretty easy to follow, Good luck and I hope you have fun, man.

[Old Sprinter]

Okay, I built a small block to replace the big motor. It is the right thing to do and I will build a big block modified, someday to put that giant in. Installed the motor plates and ready to move on to the transmission and radiator. Ken

Edited January 31, 2012 by Old Sprinter

[comp1839]

holy cow, ken! stellar effort!! keep up the killer work!

[Prostreet]

Nice work, motor looks great.

[Old Sprinter]

Thanks Dave and Joe. It means a lot to me. I installed the Brinn transmission, scatter shield, radiator and ignition system. Next up is to finish the rear and make the driver's seat and cockpit.

[roadhawg]

Lookin' awesome!! What color is the blue? I'm starting on an asphalt car and need that same color....or close to it.

[Romell R]

THIS IS FABTABULOUS!!!!! is that a word? Well it is now.... Great job on the motor and all the fab work tranny looks great too. one question looks like the drive shaft will be at an angle to connect to the rear axle tranny seems to be sitting just a lil on the high side, or is that just picture perseption. (picture perseption?? ) or do these cars run that way?

[Old Sprinter]

Thanks Tommy and Romell. The color is a Tamiya TS-19 metallic blue. The transmission lines up with the crank shaft and there is only a quarter of an inch ( scale 2") difference between the output universal joint and the center section pinion of the rearend. The rear needs to raise up slightly but I think you're suppose to have the driveshaft on a 3 to 6 degree angle downward. Could be wrong, but that's the way open wheel cars used to be. It does look a little goofy in the picture because of the angle of the photo. Ken

Edited February 2, 2012 by Old Sprinter

[Romell R]

Thanks Tommy and Romell. The color is a Tamiya TS-19 metallic blue. The transmission lines up with the crank shaft and there is only a quarter of an inch ( scale 2") difference between the output universal joint and the center section pinion of the rearend. The rear needs to raise up slightly but I think you're suppose to have the driveshaft on a 3 to 6 degree angle downward. Could be wrong, but that's the way open wheel cars used to be. It does look a little goofy in the picture because of the angle of the photo. Ken

Yeah I thought my eyes could be playing tricks on me thx for clearing that up buddy.