I am building a new front engine dragster and it is a challenge. Between the MW Plans ans SFI there is a ton of conflicts, but that I can deal with. My current problem is while bending my back support tubes my tubing bender put a kink on the inside of the bend, it didnt distort the look of the outside of the tube. I cleaned it real well and took my tig torch and filled the kink. I used low heat to burn into the metal and then took a 1/2 drum sander and cleaned it all up and it looks perfect. Does anyone think this will be a problem when getting chassis cert. I would like to thank you in advance for any help and as soon as I can figure out how this posting pic's of the project works I am going to start a thread on this build. Another challenge to this project is I am not the standard sized front engine guy, I'm a monster! Thanks Again, Blender
Good thing you didn't post any pictures! I'm sure dre will set you straight . . . In any event, what bender are you using? Sounds like a manual deal to me. I had to switch to a motor operated deal on my dragster because of that same reason. The hossfeld we were using to bend the tubes would kink the tube out past 20* or so. Took the tubing up to a local drag chassis shop and made the bends on their bender. You didn't say what tubing you are using but evidently the thin/.065 chromoly is almost impossible to bend on the manual setup with the 10ft long bar. The original hossfeld we started with bends .100+ wall mild fine but couldn't do the thin stuff
The Mark Williams plans are SFI correct. In the past the only way you'd get dimensions on the plans was to buy the entire kit, is that what you have? You cannot grind any welds, the chassis spec guys want to see the raw metal. If you have the MW kit then don't deviate or 'improve' it, it is about the best avaiable and you'd have to build a few of them to make any kind of change. The only Xmoly i have trouble with is maybe 1 1/4ish and up with .058 wall, i use the protools oneshot hydraulic for xmoly. I recall that a fair amount of tubes in that kit are probably .042ish and eggshell thin, i'd replace all of them with .065 the weight difference is minimal and you'll be able to weld & bend it (althought i don't remember those being bent as they were uprights and diagonal braces). The chassis inspect will like the thicker wall size. Take up DRE's offer and give him a call. He's done this before. King chassis & Rooman as well. Good luck, oj
No such thing as .042ish in 4130. In some places on the car .049 is legal but in most areas the minimum is .058". A ProTools bender will bend .058 up to 1.5" without any problems provided that you use a big enough radius die. Mine does 1.25" at 4.5" rad with no issues. The 6" x 1.5" deal can be a bit iffy depending on the quality of the tubing so I do mine on a full mandrel bender that I have access to. The only issue that I have with the Mark Williams blueprint (and I qualify that by saying that I have not seen one in quite a while) is that it uses the top and bottom loop design like a Don Long chassis and it requires a forrest of vertical tubes at the rear of the seat to pass tech. The Woody style cars with the lower rails sweeping up to the shoulder hoop usually end up looking a lot cleaner. Roo
Kinda new to the FED game, but here's what I found when I got to that point on mine (not an MW design): If you are talking about the horizontal "wrap around" tubes, I personally think they should be a large enough radius to match the shoulder loop. There shouldn't be any trouble bending it in that case. I bought a Speedway 1 X 6" die and modified it to fit in a Pro / JD2 style ratchet bender. I'm using it for the back supports and the helmet restraint tubes in the cage. It bent 1 X .065 mild steel with no problems (that was a test, I know they need to be .118 MS). I do know you will likely have problems if tech finds evidence of grinding on the tubes.
I talked with the OP, the wrinkle was in a transitional bend (horiz to vert) and small enough not to comprimise integrity when considering all the other tubes around that area. Filling the divot and polishing it off brought the strenght back now because there is no surface interuption and the result is that spot is just a little thicker on the inside where it does not matter. There are things a person can do when building their own personal car that chassie builders cannot. Since we are paid for a service, our customers demand perfection, so in that we would bend up a new peice in that case and use the straight parts of the damaged peice for uprites. One would have to be pretty blatent about grinding on the chassie before any chassie tech would even notice and they generaly stay away from bends since they are already comprimised from the act of bending. No problems at all bending .058 up to 1.5dia with a Hossfeld, keep your bending shoe polished and greased and it works fine- don't and it pulls the tube out of the holder enough that it will kink. Roo- liked the "vertical forest" but with the DL style including the kidney bars, my count around the driver is 5 verticals vs a Woody which is 6 (7 for 2.2spec)
Bruce, I agree that the Woody style requires more tubing but I like the visual of the lower rail tubes angling in as they go up to the shoulder hoop rather than the parallel (or close to it) look of the two hoop version's uprights. Roo
Thats why there is more than one flavor of ice cream. But the real reason for the double uprite over the lower hoop design is that most everybody does not have the availability to bend that radious whereas most can do the double uprite with the 6"
I thank you all for the help and suggestions. This was a lot to digest and DRE was a ton of help! I got off the phone with him and was so Jacked up I almost finished the chassis. I ran out of 1.5 tubing so waiting to get another stick Monday. I have a Carey Round Tubing bender and it works pretty well in bending most .058 stuff this was just i big bend on the back uprights. Since I am so big it seems to be a better look as wide as the shoulder hoop is. I haven't bent the shoulder hoop yet and may order one just so I don't have a problem but not sure yet. I was using 1 5/8 .095 but due the the reinforcement tube I have stepped back down to the 1 1/2 .058 just so there is not any problems. I am building the car to the 2.4C spec but not planning on running it that fast. I just want to start having fun again and since I own a powder coating shop I am building the car to drum up biz for coating and be a little more simple than the rear engine car. I would like to know if the chassis can be coated before getting certified. Thanks everyone and Dreracecar is the MAN!
It can be coated before getting certified, since the cert tag is a sticker your powder coat oven would burn it up.
x2. I left mine uncoated and the tech gave me a hard time after I told him I was getting it powdercoated later that week. They want to put the sticker on then considering you could take the sticker and put it on something else.
The way the sticker is made, If you were to pull it , the words VOID appear and is all that is left on the chassie and the sticker is clear where the VOID was. So , if there is any doubt on wether a chassie is spec or its your fist build the you get a pre-inspection if it passes, maybe the tech will hold the tag till its painted and then a quick inspec before its applied. I am going to make some sugestions now----fair warning If this is going to be raced (non cackle or show) refrain from PC. First if this is your first build and the car has never been fully assembled and run a few passes, then you might have some changes or add-ons to the chassie, so there goes the paint. Second, trying to remove PC for repairs is time consuming with anything left behind leaves a chance for weld contamination and any grinding reduces wall thicness.Then after any repairs one has to re-finnish the area which is difficult due to PC thickness. The type of finnish one needs for a working chassie is Electrostatic. That is a wet epoxy paint that is charged thru the gun and will wrap around the tube to reduce overspray and smooth high gloss, My frame has had this same finnish for 17 years and still looks good. Any repairs made to my frame have had the paint removed by a propane torch and a wire brush and since the paint does not have thickness of PC, touchup can be handled by a small touchup gun or spray-bomb.
Forget it it'll pass cert. or not...most probably not..! Just how much is your butt worth ? Seems to me, espicially if your a bit on the large size, is you'd want real protection, all the way around you...! Not some welded crap you're trying to sneek past tech. ! What, you don't have a wife, a mom, kids, friends who'd want to see you survive any sort of on track crash...? Not with trying this type of garbage. Mike
When you finish with the chassis go over it with a scotch brite pad, it will have kind of a brushed aluminum finish (I seen one where they polished the tubing, looked like chrome)then clear powder coat it. Just don't touch the tubing afterwards with your bare hands (skin), it will rust underneath the powder coat where your skin touched it.
Mike, did you bother to read Bruce's post re the conversation that he had with blender re what he had done? Bruce is one of the best chassis builders around and he does not do anything that is not right. If he signed off on the fix it is good to go. Roo
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