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Race Car Fabrication There is a lot of cool fabriaction going on the race car industry, show us what you got.


Race Car Fabrication There is a lot of cool fabriaction going on the race car industry, show us what you got.

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  #181  
Old 02-16-2015, 09:36 AM
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I was going to do radiators next, but my good friend and driver Mark came down over the weekend to get the pedal placement right, and since I had an extra set of hands to help, we got a set of headers tacked together.

Here's the left side:



The pipes are all pushed out at an angle to clear the oil tank. The collector is about 2" from the tank at its closest point. These are all mild steel tubing. I had researched stainless, and it wasn't the pipes that were too expensive, but I couldn't come up with a muffler for this application in stainless that wasn't several hundred dollars.

The first 2" out of the flange is 1-3/4" tube in order to fit the flange. I am now painfully aware of why the spread port exhaust pattern was developed for small block Chevy's. Anything larger than a 1-5/8" primary tube is really pushing it in terms of getting everything to fit. I formed the ends that go into the flange square by using a tool that I made, which is essentially a 1-5/8" square in a piece of 1/2" plate, that was split in half. I used the press to force this down over a short piece of tube to make it basically square on one end. I'll still have a bit of hand work to tune up the fit in the flange, but this was much better than doing it all by hand.

This was my first real attempt at using several bend radii to make a cleaner looking piece. The primaries transition to 1-7/8" tube after the initial 2" off the flange, and have 3", 4", and 6" bend radii to get the look I was after.

Here's the right side:



Pretty much the same idea as the left, but kept close to the car to try and keep as much left side weight as possible. I kicked the collector out at the end to make sure it will always clear the suspension.

The collectors are from Cone Engineering and they're much nicer than the "one size fits all" stuff that comes in a normal header kit. They're dedicated 1-7/8" parts, which will make welding them to the primaries much easier. The mufflers are Shoenfeld pieces that are spec'd by nearly all sprint car sanctioning bodies. They're intended to keep the noise level below 100 dB at 100'.

I have a few hours of final welding and messing around in front of me, then I can check "headers" off the to-do list.
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  #182  
Old 02-16-2015, 11:32 AM
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Looking good. How do you weld the center of the tubes going into the collector?
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  #183  
Old 02-16-2015, 12:23 PM
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Fwiw

Last open-wheel I welded headers for, I turned the dumps down to avoid them being tire heaters. Tech didn't like so I ran behind the tires, which boosted torque...
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  #184  
Old 02-16-2015, 01:43 PM
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Originally Posted by deaner View Post
Looking good. How do you weld the center of the tubes going into the collector?
The pipes all end up coming out of the flanges to be finish welded, then put back together. After that, I have what Cone calls a "merge bullet" that caps the void between the four pipes. It also takes up some of the volume inside the collector so it behaves more like a true merge collector.

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Last open-wheel I welded headers for, I turned the dumps down to avoid them being tire heaters. Tech didn't like so I ran behind the tires, which boosted torque...
Interesting. I know they don't like you to point the turnouts down because it makes for a dust storm in the pits at places that don't have them paved. I could run a long tailpipe on the right side, but not the left...there's no clear path to the back of the car. Plus, I don't know that more torque is going to be helpful on a hard RR tire without a wing. Maybe a tire heater will be? I dunno.
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  #185  
Old 02-18-2015, 01:48 AM
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  #186  
Old 02-18-2015, 09:32 AM
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You make me want to be a better man.
You're giving me waaayyyyy too much credit.
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  #187  
Old 02-18-2015, 12:36 PM
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Quote:
Originally Posted by deaner View Post
Looking good. How do you weld the center of the tubes going into the collector?
I don't want to dirty up his thread with my stuff, but I did a picture walk through of how to do Cone engineering style collectors. I just used a star in between the pipes as opposed to the merge bullet.

http://www.turbobuick.com/forums/thr...-build.373892/ It starts on post 15.
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  #188  
Old 02-18-2015, 12:59 PM
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Originally Posted by MeanMike View Post
I don't want to dirty up his thread with my stuff, but I did a picture walk through of how to do Cone engineering style collectors. I just used a star in between the pipes as opposed to the merge bullet.

http://www.turbobuick.com/forums/thr...-build.373892/ It starts on post 15.
Not cluttering at all. That's exactly the same process I use for formed collectors, but it should be easier (better gaps) with the Cone parts than what I've used in the past.
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  #189  
Old 03-23-2015, 08:27 AM
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A long overdue update.

I got the headers finish welded so everything is good there. I had mentioned the Cone Engineering "merge bullets" that cap the void between the four primary tubes. Here's a picture:



The come as four separate pieces with a little jig to position them for welding. According to their site, the performance of their collector with this installed is very close to running a 4-1 merge collector. I figure it can't hurt anything.

Another thing I did this time was to TIG braze the outside of the flange joint. I've read that the combination of welding the head side of the flange, and brazing the outside makes things more fatigue resistant. Again, I figure it can't hurt anything. Here's a pic of that:



One thing I learned is this runs on AC much better than DC. The cleaning action of the AC arc makes a bright shiny gold bead. I had a hard time getting anywhere close to this with DC, plus I kept melting the base material on DC because the arc is more focused.

From there, I started making a pair of radiators so I could have one in the car and a spare. The configuration I'm running allows be to get two radiators out of one core, so I have about $65 in each one.

Here was my starting point...the core is 22.5" wide by 19" high.



After cutting down to roughly 8" tall. You're limited on exact dimensions because the cuts have to fall on a tube.



Left tank added to both. This gets a single fitting on the top for a bleed line back to the header tank. I planned ahead and punched it prior to forming the tank. This side is only 1.5" wide so I could end up with 26" total width, allowing it to just fit in the frame.



A quick mockup after adding the left tank:



A little detail of what's going on inside the right tank. I make all my radiators two pass, so the plate forces incoming water to go across the core to the left tank.



Finished! The lower neck is 1.75" to work with a stock type SBC water pump, and the upper is 1.5". It's getting connected to what's effectively a water manifold to collect the water coming out of the Hilborn injection.



The fitting on the left tank is -4 O-ring port style. I have pretty much sworn off NPT threads after having one gall when I was pressure testing the last radiator I built.
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  #190  
Old 03-23-2015, 09:34 AM
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I love o ring ports. I used to make a lot of custom plastic dispensing manifolds (for lack of better name) and NPT would cause them to crack. SAE o ring was the ticket. I bought cutters from Scientific Tool in Simi Valley, CA and used hydraulic fittings.

You're my hero for building your own radiator.
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  #191  
Old 03-23-2015, 10:54 AM
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"I've read that the combination of welding the head side of the flange, and brazing the outside makes things more fatigue resistant"

Ron Fournier's book?
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  #192  
Old 03-23-2015, 10:56 AM
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Me too. I have finally arrived at the conclusion that pipe threads are for plumbers. They do the job, but there are better ways if you're willing to spend the money and effort to do them.

I haven't invested in port tools yet. I got -4 bungs from Summit that are made by Fragola for something like $6 or $7 each. I can buy a lot of those for the price of a port tool from what I've seen.

The last pipe fitting that screwed up on me about causes heart failure. I was able to fix the radiator by chasing the fitting with a tap and using liberal quantities of Loctite 565, but that's not my preferred mode of operation.
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  #193  
Old 03-23-2015, 10:58 AM
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Quote:
Originally Posted by bullnerd View Post
"I've read that the combination of welding the head side of the flange, and brazing the outside makes things more fatigue resistant"

Ron Fournier's book?
Yep. I've seen it done several different places. I have fully welded the outside of the joint, but it leaves the inside of the pipe looking like it would crack.
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  #194  
Old 03-23-2015, 11:16 AM
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A couple more photos from this weekend. Mark came down to work on the car. We tackled making nerf bars since those are much easier with two sets of hands around.

Right side first:



We made a double row design because most of the places we're racing at are pretty tight. For the most part guys race pretty clean, but contact is inevitable due to the close quarters. Material is 1" x 0.065" 4130.

I was hoping we could reuse the design on the left side, just shorter, but no such luck. Turns out the bottom bar was right in the center of the exhaust exit. In the interest of being able to keep paint or plating on the nerf, we modified the design a bit to move things away from the header.



We also made a second back bumper while we were at it. This is mostly 1" x 0.095" 4130, with a little 0.065" used for the forward uprights. Because this is also the starter, it needs to be pretty sturdy. The heavier wall also keeps it from getting dinged up if someone uses the "chrome horn" a bit to let you know they're back there. The very top loop on the back is because the cars are so low relative to the bumpers on the push trucks. It helps keep a push truck from potentially climbing on the back of the car, which will really ruin your night!

Last edited by Graham08; 03-23-2015 at 12:46 PM.
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  #195  
Old 03-31-2015, 01:14 PM
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Since I was in the bumper/nerf mode, I went ahead and got the front bumpers taken care of.

Originally, I made front bumper mounts using slot clevises from Chassis Shop that were stuck in a short piece of 1" tubing and welded to the top of the front crossmember. After really thinking about it, I was afraid that the lack of weld surface plus the height could lead to a chunk of tube getting popped out of the frame in a front impact. I revised the mounts to be double shear tabs, and much shorter. As an added benefit, the bung in the end of the bumper is more robust than the original plan:



Here's the second bumper I made. Just a slightly cleaned up version of my original design:



Then I got back to getting the radiator in place. The first step in that was making a lower pan to locate it. The pan is 0.040" thick aluminum, with a channel riveted to it for the radiator to sit in. I got 1/8" thick neoprene strip from McMaster-Carr for a little vibration isolation.



This was attached to the frame with tabs that have #10-32 plate nuts riveted to them.



Radiator in place:



A closeup of the mount. There's an 3/16" aluminum tab welded to the upper channel on the radiator, and a 0.090" steel tab welded to the frame. The blue thing is a bushing I got from McMaster that has a 7/16" hole in it, with a 3/4" diameter shoulder to go through 0.090" thick material. This gives some vibration isolation for the upper mounts. I made up aluminum pieces that go through the bushing and give something solid to bolt to.



Here's the completed radiator shroud sitting on my stool. I wanted to be sure as much air as possible is going through the radiator instead of around it. I still need to make up a rock screen to go in the duct so debris doesn't find it's way to the radiator.



More coming soon. I'm working on getting a header tank made for the radiator cap, followed by plumbing the cooling system.
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  #196  
Old 03-31-2015, 01:44 PM
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Originally Posted by Graham08 View Post
Of all the highly specialized RaceVehicles I have ever seen, built, or worked on: it is this segment of the Racing world that has the best drop dead sexy lines of any other class. I have often thought of building one though, for turning right too, on the street... Sort of the ultimate Track-T. Never will at this point but I do think about it once in a while


E
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  #197  
Old 03-31-2015, 02:24 PM
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Graham,

I have built several radiators in a similar way, of course most of my cores have come from the junk yard. Many times though I have found one that was the right length but the wrong width and I've never thought of cutting one down the way you did. Thanx for the tip. Can you show a close up of how you weld the tank to the cut area?

Thanx and keep up the good work.
Jaysin
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  #198  
Old 03-31-2015, 02:51 PM
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Quote:
Originally Posted by entropy View Post
Of all the highly specialized RaceVehicles I have ever seen, built, or worked on: it is this segment of the Racing world that has the best drop dead sexy lines of any other class. I have often thought of building one though, for turning right too, on the street... Sort of the ultimate Track-T. Never will at this point but I do think about it once in a while


E
I've thought about scratch building some sort of a roadster with most of the design of a sprint car. Someday...

Quote:
Originally Posted by JaysinSpaceman View Post
Graham,

I have built several radiators in a similar way, of course most of my cores have come from the junk yard. Many times though I have found one that was the right length but the wrong width and I've never thought of cutting one down the way you did. Thanx for the tip. Can you show a close up of how you weld the tank to the cut area?

Thanx and keep up the good work.
Jaysin
I don't have a real great pic of that area...and it's covered up by the channels on the top/bottom.

If you look close at this pic, you can see how the ends of the top tube are folded down:



What I try to do when I split the core is to cut right down the center of the last tube, but if I miss, I want to be in the waste area of the core. I'll clean up the remaining half a tube with a 3" Roloc on a die grinder, leaving the half of the tube that's brazed to the last row of fins.

Then I dress down the top/bottom of the end plates, just grinding through where the tube is attached. I then push the end of the tube and the fin material down toward the first full tube. This gives me access to the end of the plate to clean it up and weld.

It's a lot of typing, but I could probably show you in 10 minutes. We had a member, dqracer, that did a thread about his 600cc kart, where he shows the process. I got a lot of info there, and I cut up a C&R radiator that I had with a hole punched in it to see how it was put together to fill in a couple blanks.

I'm not going to lie, even though these are the 4th/5th radiators I've built, I still get nervous taking the bandsaw and grinder to a new core!
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  #199  
Old 04-02-2015, 02:46 PM
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I haven't invested in port tools yet. I got -4 bungs from Summit that are made by Fragola for something like $6 or $7 each. I can buy a lot of those for the price of a port tool from what I've seen.
You can get a HSS port tool for about $120 (-6 or -8) from Form Relief Tool Co:
http://cutters.formrelief.com/viewit...ontour-cutters That's roughly half the cost of the carbide-tipped version from Scientific Cutting Tools (I needed carbide for stainless). Having this kind of tool really opens up options for custom manifolding, port repairs, and whatnot, but it's an investment. I found myself using them all over the place once I had the tools, but I was also dealing in a manufacturing environment where maintenance, down time and lost product (catalyst coatings containing expensive precious metals) were very expensive. I also didn't deal as much with tanks where you need to add a bung anyway for thickness.
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  #200  
Old 04-02-2015, 07:51 PM
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Awesome work and build project , radiators are beautiful ..
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