Sprint car build thread.

[racrguy]

I started this thread in the corner carving section of the boards, but then it dawned on me. Most of the people that visit there are already into racing, so I need to post this in a section so that people who don't know squat about dirt racing, or sprint cars specifically, can see what goes into one of these machines.

I'm going to take you from this:



To this:



All of the measurements and whatnot have been done already, and all the plumbing set, so I won't touch much on that, but you'll see how one is put together.

[racrguy]

What do you need to get a sprint car on the ground? You need the chassis above and all the parts below that I'll list out.

First off, the whole shot:



Now for the smaller close ups, starting from the front of the car:



In that picture is a front axle assembly, RF torsion arm, LF torsion arm, 2 torsion bars, 2 torsion bar stops, 2 shocks and 4 radius rods with heims.

In the center of the car:



Here you have a drag link, pitman arm, steering gear and reservoir, rear motor plate, torque ball and housing, a shifter and a master cylinder with residual valve. (you can see part of a torque tube at the bottom of the picture)

Now a bit farther back:



Here you can plainly see the torque tube and rear end, it looks odd, but you'll understand how it all goes together later.

Here's a picture of the driveshaft, which I forgot to lay out. Have I mentioned titanium stuff is light? The only steel part in this picture is the snap ring and the swivel splined portion to the left of the picture, it slides over another splined portion of the driveshaft so it can be replaced when/if it wears.



And now for the rear suspension pieces:



Here you have 2 more torsion bars with stops and arms, a couple more shocks, 2 more radius rods, bird cages, which are the rear suspension attachments that double as wheel bearings, a right rear brake and caliper and the jacobs ladder, also known as a watt's link.


As of this moment the car is on the ground and I'm going to write up another post tomorrow, time willing.

[naynay]

epic fail

[YALE]

[idrivea4banger]

I'm not sponsoring this shit with my tacos.

[WesB]

Um, been there done that, but glad to see you're finally getting a car back together. Looks like if I want to work on a sprinter I'll be going to Indiana.

[racrguy]

epic fail

God dammit! I moved the pictures to different folders and figured the links would stay the same. Calmate su chichis jotos!

[YALE]

Ok.

[slow06]

Awesome, this will be cool to watch go together. I go to the dirt track races in Kennedale every once in a while with my wife's family, the sprint cars are always one of my favorite parts.

[BMCSean]

Is there a way to make it "stanced"?

[Mike]

Looks slow

[racrguy]

First, we'll start with the front end

In this picture I've got the pahard rod installed just to hold the front end centered in the chassis. Now, these axles aren't exactly centered up, they're offset 1" to the left side for the combination steering arm to clear the torsion arm.


Here you have the left side radius rod connected, its sole purpose is to hold the axle's fore and aft position.



Here on the right side there are two, which locate the axle fore and aft and set the caster angle. Depending on driver preference, caster will be set between 7 and 18 degrees, I like 12 myself.



Now it's time to put the torsion bars into place and set the ride height. When you square the front end, you'd use a 5" tall block, since that's done and we're setting up the race ride height, you use a 3" block underneath both sides of the axle.



And guys, don't forget to lube your bars before you put them in the tubes.



When you slide your arm on, you want the stop bolt (shown later) to be up against the pad, and the arm resting on the axle. Before you tighten the arm on the bar, you want to make sure you've got about a dime or nickle's width gap to allow the bar to move freely as the suspension works up and down.



This is a stop and stop bolt that I mentioned earlier, these bolts are what adjust the preload on the torsion bars, which act as the springs for the suspension. For those of you that are familiar with racing news this is the stop that came off and caused the wreck that took Jason Leffler's life. To say that these parts are extremely important would be an understatement.



And here you have the front suspension all together, save shocks.

[WesB]

You're making this look easier than it really is. I know those torsion bars are bitches!

[racrguy]

You're making this look easier than it really is. I know those torsion bars are bitches!

It really is as simple as it seems. Now, getting everything squared up and set right is a motherfucker, but putting in the bars is simple. How do you guys do them?

[WesB]

rubber mallet and cussing!