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Modifying a chassis to meet spec

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andrewb:
I have a couple of questions regarding chassis modifications in order for it to meet the SFI 2.6A Spec, which I own a copy of (should be free if you ask me). I need to remove or replace several of the back half uprights as well as the expanded metal “seat”, that’s welded to the frame. I didn't find anywhere in the spec about grinding on the frame rails. I only plan on removing the welds but, you know, things happen and I could unintentionally hit the rails.

Unless it’s completely obvious, do they even ask or look for such things when inspected a car? Anyone here have any tips or advice getting this hot rod up to date?

Thanks,

Andrew

janjon:
You might want to survey the entire back half for wall thickness. that chassis looks to have been around long enough for possible corrosion from the inside... Do you have access to an ultrasonic thickness checker?
John

andrewb:
Ya, I planned on checking it out closer once I get it home. I know of someone with a ultrasonic thickness gauge, we used it in the past to check cylinder walls.

Andrew

janjon:
I haven't had a chassis certed, but it's my understanding the inspection will be pretty thorough .(And pretty expensive. $400.00 I think?) At the very least, if you find sub-wall thicknesses, your car doesn't look like it would be that hard to back-half partially or entirely. It's not a good feeling to realize you bought a car that won't pass, and there are umpteen flippin' uprights that would have to be cut loose from a shoulder hoop that checks .002 too thin, EVERY other piece of tubing checking to spec. Ask me how I know...
 Said shoulder hoop has a couple of grinding nicks from when I cut off the old cage, and has some small holes I suspect are snap-attachment upholstery way back when; I also suspect the existence of those holes permitted some (slight?) corrosion from the inside. My intent is tig them up and smooth them off for appearance. I forget where it prohibits grinding of structural welds, whether it's SFI or NHRA, but I don't see filling and filing a nick otherwise as a no-no.
 One thing's for sure, there are a good several knowledgeable and experienced chassis building pros and others on this site who will give guidance, tips and tricks of their trade to us folks who want to do this ourselves. Ask me how I know...
 Anyway, Welcome, Andrew. You'll find this site to be a gold mine.
John Williams
 

masracingtd1167:
I think my last re cert was 150.00 . As far as the chassis passing they only check the driver area . The only problem you might have is the tubing thickness . A lot of the old cars were made out of .049 and the newer cars are .058 

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