Drag Racing Discussions > Front Engine Dragsters

What to look for when buying a used chassis...

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dreracecar:
First and foremost, any used chassis even Worthy a look must have an SFI date tag on the frame , those tags have been around to close to 20 years now. The tag does not have to be current, updates to a older chassis that has been tagged are minor compared to an old chassis that never had been inspected

1000hpJohn:

--- Quote from: dreracecar on February 04, 2017, 08:30:25 PM ---First and foremost, any used chassis even Worthy a look must have an SFI date tag on the frame , those tags have been around to close to 20 years now. The tag does not have to be current, updates to a older chassis that has been tagged are minor compared to an old chassis that never had been inspected

--- End quote ---


Ok,  correct me if I'm wrong, the inspector from SFI or any other authorized inspector from NHRA or the IHRA looks for the correct tube dimensions per location surrounding the driver on each chassis being certified per that chassis spec.   The chassis inspector Pete Woodriff near Norwalk, Ohio mentioned to me that as long as the correct bar sizes are in the correct locations around the driver and have the correct supporting bars, all the other bars are just going for a ride...meaning the rest of the bars that support the rest of the chassis are not inspected!!!!

That being said, with a dragster which I believe have more to inspect from front to rear, what does the actual inspector look at besides correct size and correct  location per the chassis as per the et range and speed?  All the inspectors I have ever had only measure around the driver area.  So, am I under the assumption that all inspectors check welds too!!!!   Maybe I'm not up on this with a dragster, but they don't inspect welds correct???  So just by having a chassis number means that chassis is ok...  that is what I am concerned with, and why I asked these questions when buying a used chassis.  I'm not asking about a chassis that was built in the 60's to pass spec in today's world, but a chassis that is built in the 70's and later, has passed tech numerous times along with the needed upgrades.  So, unless the buyer checks each weld them selves, couldn't they be buying a chassis that MAY have fractured welds somewhere???    I can't believe every chassis ever built will not have any fractures anywhere whether it is 30years old or 2 years old....  I'm asking this because I just don't know, I'm ignorant to the dragster chassis itself and of course I will buy the SFI spec info., but that doesn't tell me if the chassis cracked somewhere or not.

This thread is not about tube size or placement, but about where to inspect a used dragster chassis for possible stress fractures over time racing and traveling to and from tracks... I sure wouldn't buy a tube chassis door car unless I crawl underneath and inspect welds myself which I do, so is a dragster chassis different in that respect?

I'm not trying to create a crap storm here ok?, I am only asking where to inspect as a buyer to make certain that chassis does not have fractures, That's it!   If I'm going to be running quicker than 8.50's and over 155mph, my chassis better be done right and have ZERO fractures.  I asked this question to find out if there are areas I need to look for first before purchase.  I apologize if it read differently.

John

Paul New:
I e seen several FEDs show up at the track with the lower team rail sitting on the trailer and they had to fix the chassis prior to racing again. One of the guys we race with showed up that way and we just told him to haul the car to our shop and I will weld it up tonight this was a long Friday night as I had to splice the frame rails and replace an upright or two. So what I am saying is look over the complete car!

aafa760:
John
Most likely you should buy a known builder if possible

if you have ever seen how powder coating hides cracksvery well.
most 6:00 cars will not be powder coated if it is walk away.
Strip it down to bear metal look over every weld after you buy it. Every hiem joint should be replaced with high Quality ones no grease zirts  new washers, all bolts and washers with grade 8 new ones nice new washers new nylons nuts. Unless you safety wire each one.

pull each king pin check for wobble.
new front tires if you can
The Chassis inspectors I dealt with are very good the will find small tubes thin tubes need for Kidney  bars.

JrFuel Hayden:
Yes, Paul is right,  inspect ALL of the car. The cracks that showed up on our JF was in the front, the support for the steering bellcrank,& uprights, it has cracked/broken at least two times, requiring bigger supports. That's why some chassis builders prefer drag link direct to the spindle.  We have also broke a rear motor plate and a 11-12" windsheild. We think it was from tire shake, as we made more power and worked on the converter combination we get more shake. I have seen cracked/ broken chassis rails & uprights, just from towing in the trailer, if the chassis is not supported enough. More racecars are stressed/cracked from towing than racing.
You will have to check even more closer if the chassis is painted dark colors because it's harder to see. Our chassis is orange, easier to see cracks. We wax the chassis before leaving home, it makes us look at the whole chassis.
I'm sure Rooman and Bruce can give you more info about the SFI specs, I think a chassis that was build in the 80's can be brought up to current SFI. Keep in mind having a SFI number is not enough, it needs to also have a date as to when it needs to be re-certed. The Jrfueler that Don Enriquez drives was built in the early 80's, matter-a-fact, in nostalgia racing that car has run, and won more races than anyother car racing in Bakersfield, Bruces car is no doubt close but even when I asked Mike Algire that owns the Enriquez chassis to count how many runs and wins are on the car Mike said I couldn't even guess, just too many. Anyway after Scott Parks has welded up their chassis a few times at the track, mostly in the front rails, Mike finally decided to front half the car with all new tubing from the motor on. John Farr, the JF racer that does all our chassis work agreed to front half it. BTW when John had  it on the jig he found out the rear-end was not straight in the chassis. Since the chassis update Don says it never ran so striaght, he always had to fight the wheel some. But my point is even an old chassis can work good if the motor is in the right place, ie not too far back, like they used to build them in the 60-70-80's. Mikes car is 42" out, ours is 48" out, and has been when built in 1995. Parks build their cars at least 50" out, their car was 54" out.
Keep in mind the tubing can have stress cracks too, I'm sure you have seen the video of Larry Dixon's big show top fuel car coming apart about half track, and not at the welds.
Chassis inspectors also check for tubing thickness. The way I understand chassis specs is SFI only has specs in the driver area, anything goes from the motor forward. That's why when we had John Farr front half our car so we could run our Hemi or our SBC we also had him increase the wheel base from 200" to 225" , 200 was the limt for the JF clas when it was built in 1995. John put smaller dia tubing in the front to hopefully keep the car weight down, even tho we were adding 25" to the WB. BTW the Hemi is 100 lbs more than the SBC. The last JF championship we won was with the Hemi.
I still think buying a already built car is less expensive than building your own.       
Jon, 805-444-4489

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