Roll Bar Construction

[jlmccuan]

It looks like I'll be fitting up the roll bar myself, but I have some questions.  I understand how the harness mount cross bar is placed depending on seat and driver height and also can determine the placement of the top of the bar.  Where is the door bar height determined, both at the front and rear.  I see different companies placing them at various heights.  Should I also run a sill bar?  Thanks

[t russell]

I would start the door bar at the same level as harness bar.As far as other bars go rember who is driving

[Dan Stokes]

Sill bar= good idea.  Also, run a bar across the center of the halo bar, then down to the right front corner diagonally thru the passenger compartment.  This stiffens everything and makes a great place to mount the tach and other bits.  I'm still adding to my cage - eventually, I will no longer need the car as the cage will be a stand-alone unit!

Dan

[Cajun Kid]

Dan,  may I ask if you live in NC and if so where?  The reason I ask is I may need to pick your brain on roll cage info.  I am building a vintage type LSR as a 1933 Ford Vicky Hi Boy.... I wanted to run a 255 SBC motor but just found out that the bore is to small to get the valve size and runner size to make the HP I want,,  unless I spend more on the heads than the entire body and chassis cost...  I Thought the cage was to built for the speed I would run the car, not the current record of the class,,,  from what I think I just read ... say I build a  C/CGALT car  and I only plan on going 130 mph , but the current record is say 159 mph  do I have to go by the safety  rules for the 159 mph or the rules for the speed I am going to run?

Thanks

Charles

[dwarner]

If you run any SCTA-BNI event you must build to the class record. If no record then the next highest engine class record. ECTA may be different. Please do not confuse the various timing organizations and the venues they race.

DW

[interested bystander]

If you have access to an NHRA rule book they recommend the door bar to pass -and this is from MEMORY- half way between the driver's shoulder and elbow when seated in the car. That would apply, I believe, if you're building like Figure 1 in the SCTA rulebook.

Tube fitting requires patience and it's nasty work-make cardboard tempates if you're inexperienced , strive for tight joints.

This is an unsolicited recomendation of Mr. Warner's suggestions (I don't know him, only of him).

PAY ATTENTION TO HIS ADVICE!

[willieworld]

my business for years was building race cars (DRAG RACE) you should make the door bar pass you half way between your shoulder and elbow--the shoulder bar (HARNESS BAR) should be at the height as the highest part of the door bar --as high as the top of your shoulder when seated in the driving position no more than 3 inches below your shoulder and no higher than the shoulder--i think that will aford you your best protection  and a good harness angle   just some thoughts  willie buchta

[Cajun Kid]

The horizontal bar that goes behind the seat (that the shoulder harness bolt to or wrap around.. It was my understanding that it was to be at least 2" to no more than 4" below the top of the shoulders. So that the shoulder belts went slightly up and over your shoulders, then down to latch with the waist belt ?? 

I was told to build the main loop first, install the seat, then weld in the horizontal bar as to make sure it met the 2" min and 4" max below the top of shoulder.. I was also told to make sure when the belts go through to opening in the seat that they do not touch (if using a race seat that has passage ways for the shoulder belts, like a Kirkey or Butler seat)

Gosh,, I sure hope I have not bitten off more than I can chew ??

[willieworld]

sorry no higher than the shoulder and no lower than 3 in below top of shoulder when in driving position nhra also requires something to keep belts from sliding side to side on bar if wrap around belts were used --remember all of the rules are minimuns a extra tube or two is good insurence     willie buchta

[Cajun Kid]

I hear ya Willie,  I am going with  1 3/4 DOM  .120 wall thickness for the entire 8pt. cage. 

If I weld the cage in, I can never get the body back off.  If I weld the cage legs to 1/8" thick  plates 4x6 in size ans bolt them through the follr to the the same size plates over the frame rails and crossmembers with 7/16 Grade 8 bolts will that be strong and safe enough?  (car is a glass car, so making sure the plates are bolted to each other on the frame is a must)

What do you think?

Charles

[willieworld]

I looked in the SCTA rulebook and they require a plate that is 1/4 inch support pads and a sandwich construction - if the car is less than 2500 lbs. the pad should have a perimeter of at least 18 inches ie. 4x5. Cars over 2500 lbs. shall have at least a 22 inch perimeter ie. 5x6 all bolts must be 3/8 min. diameter and a grade 5 min. I would reccommend a grade 8. All bolt structures must have at least two bolts 180 degrees apart through support pads and roll cage structure and brace connections. But I would reccommend 4 bolts that are grade 8. Its sounds like to me that if you weld a pad to the frame and a pad to the rollcage whereever it meets the frame and bolt the pads together with four 3/8 grade 8 bolts on each pair of pads you would be above the minimum on the rule. Do you have a rulebook?
Where are you going to race at?

willie buchta  349b

[Cajun Kid]

Willie,  to answer your questions. For 2008 I am going to run at Maxton, NC .
(I hope to make the April event, and not embarras myself going through tech the first time, that is why I am asking so many questions)  I sure wish I knew some racers here in NC that I could run stuff by or visit with.

If things work out I may try to run the USFRA event in the fall. (130 and 150 club)

I just got my membership card and also my car number  (#5690 is mine now)
I have a ECTA  2007 rule book, hope no major changes to car rules for 2008.

I will use  1/4 "   pads "sandwiched"  as you suggest and grade 8 bolts.

Thanks for your help.

[willieworld]

i read the scta rule book i dont have a ecta book -- ive built drag race cars  street rods and bikes my hole life and there is one thing i found out in the beginning and that is --whatever the mininum is in the book give them more it makes tech very happy and in case of an "upset" you will be much happier also  thanks  willie buchta

[LittleLiner]

I am not an official of any organization but know a bit about the rule books for SCTA and ECTA.  I would say that when it comes to safety gear for cars, if you build to SCTA specs, 99.9 percent of the time (if not always)you will be OK for safety tech inspection at Maxton.  I some cases the Maxton safety rules differ and could be called less strict.  There are good reasons for this such as Maxton speeds are lower and the track is only two miles total from start to end of long shutdown.  Before his death I was fortunate to have the chance to ask John Beckett (first President of ECTA) several questions about building a car for Maxton.  He advised me to build to SCTA specs if for no other reason than to save reworking the car for Bonneville.   You might consider contacting Joe Timney or Keith Turk with specific questions.

[jlmccuan]

Bender, dies and coping fixtures are in, but I have to work in Tennesee this week.  But I'll be bending and forming this weekend.