Was not going to make a thread on this until I had some more facts and answers but feel maybe a discussion and possibly a fresh perspective is needed. The background... I enrolled in the Frank Hawley drag racing school to get some education and one on one seat time in the Skyhawk. This car is totally different than anything I've ever piloted in the past and just a very few on here have driven something like this. Its a bit intermediating and a little scary so I feel the school is a good idea. Part of this is the car has to have a current chassis cert. Last Sat I trailered the Hawk 150 miles north to meet with a NHRA inspector. The guy whipped out his tools and started to do his thing. A sonic tester for wall thickness and some sort of "wrench " to tell the diameter of the bar. After a few mins of checking stuff he says the bars are to thick to be Molly and to thin to pass if mild steel so he failed the car. I have it on the best authority the car is in fact Chrome Molly tubing and was built on purpose with a thicker bar. Now I have to find a way that the NHRA will accept to prove it is what we say it is and get that cert before Dec 12 class date. Does any here in the Buick universe have a concrete method of telling one from the other. I have been in touch with the shop that built the car but its been too many years and they have no records. The last 2 owners have had good certifications on the car over the last 30 years of its life. NHRA does not keep records for very long. Past inspectors are not answering the phone, returning calls or emails. Whats a guy to do?
Sounds like the guy who didn't pass it didn't know his stuff. Is there another person who could do the checking/testing for you? I highly doubt the Csordas's had a car that wasn't up to snuff or correct. A second opinion might be invaluable...
Here's a thread on Yellowbullet. There's a spark test, which you could try. It may be difficult to see much difference between the two metals. The centerpunch test may also be indeterminate. The acid test should give you a definite answer. https://www.yellowbullet.com/threads/telling-if-chassis-is-moly-or-mild-steel.1841858/
Using small drill, drill hole, capture and have chips analyzed (Material analysis lab). Weld fill hole, clean and paint.
That was what I was wondering as well... My chassis guy is Tig welding my mild steel cage as he wants to do it that way. I didn't argue with him either..
Yea you absolutely can and it certainly looks better....most chassis guys will only use molasses it's the thing they are most used to..machines are setup for...etc etc...the cost isn't that much different
You can get DOM (drawn over mandrel) seamless tubing in either mild steel or CM. It would be unusual for any chassis builder or chassis parts vendor to be selling welded tubing for building a race car. Mike P has the answer here.. material analysis will be the difinative answer to the question. The biggest hurdle your going to have is to find someone to do the analysis, and have it done in your time frame here. JW
Last time it was certified was by me and was done by IHRA. I was told everything was good and they would only cert to 8.50 because it needed 2 more bars installed (which me and John Jr knew about from the start)
Just some info if you need it, but i'am guessing you already know Chromoly is a stronger material than mild steel, and that allows for Chromoly to be a thinner wall tubing (.083″ compared to .113″). This gives Chromoly a distinct advantage in terms of weight, but that advantage comes at a cost that customers must weigh (no pun intended) before they build. Mild steel is far less expensive than Chromoly but comes with the disadvantage of more weight. For the grassroots racer on a budget that we're targeting here, that cost versus weight decision can be a big one. I know the spark test is a very good source for identifying 4130 chromoly from mild steel.
Vet, What your saying used to be absolutely true... back when the steel was cheap, the alloying process for CM caused it be more expensive.. but as steel prices increased, the mild steel tubing, because it has more steel in it (thicker wall) is now often more expensive than CM... just did a quick check on a retail outlet online.. price difference was $8 bucks, with the CM being cheaper. It's a crazy world we live in now.. JW
Here is another test that can be done. Try a magnet. The magnetic attraction should be more on the MS than the CM.
As i told you in text. The car is chromoly and was built thicker to last since the previous owner before me wore out 2 cars with the amount of passes he put on them. The nhra inspector you got made a mistake and assumed its mild steel. Get A NEW INSPECTOR. The car is legit and has passed by 2 different inspectors when i had it and 1 more different guy when Denny had it. No need to drill or check unless the guy does it himself because he probably wont believe you anyway. John jr
the reason is because its chromoly but the inspector didnt believe Briz. He said nobody would do a chromoly car with thicker bars when the minimum is .083 Well the car was built to last since previous owner to me wore out 2 chassis in his career with so many passes. The guy raced every weekend at 2 different tracks on saturday and sunday. This inspector just made a mistake and cost Briz his time and money. john jr
Unfortunately for Briz, NHRA is making the rules here.. While you might have luck with one of the other 14 chassis inspectors they have for Division 2, I wouldn't bet the ranch on that.. Call or email the division 2 Tech director, and ask him what it is going to take to prove the car was built with thicker than required CM. He runs the tech department for the division, I would have him draft you an email stating what is required, that you can show the next inspector. JW
Agree with all the above. You can't DIY this. Someone with authority will have to do the certification - like a lab. Good thread! I have a buddy in the metal trade and I've been trying to get a hold of him but with the holidays... If I do and he has some good ideas I will pass them on!
