Moly cage

[evldoer]

Can anyone with an NHRA rule book let me know if on a moly roll cage, can a smaller diameter bar be used for the dash bar, or do I have to stick with 1.625?

[1SLO5.0]

4.11 ROLL CAGE

All cage structures must be designed in an attempt to protect the driver from any angle, 360-degrees. All 4130 chrome-moly tube welding must be done by approved TIG heliarc process; mild steel tube welding must be approved MIG wire feed or TIG heliarc process. Welding must be free of slag and porosity. any grinding of welds prohibited. Additionally, roll cage must be padded any where the driver's helmet may contact it while in the driving position. TAD, TAFC, Pro Stock, Funny Car & Top Fuel padding must meet SFI Spec 45.1.

Open Bodied cars

When driver is in driving position in an open bodied car, roll cage must be at least 3-inches (76 mm) in front of helmet. Cars without crossmember above driver's legs must have a strap or device to prevent legs from protruding outside chassis. On front-engine dragster, seat uprights and back braces must be arranged such that a flat surface passed over any two adjacent members will not contact the driver seat or containment. Additional uprights, max 30-degrees from vertical, must be added until this criteria is satisfied. When non-vertical upright or "running W" side bay designs are used (diagonals installed at greater than 30-degrees from vertical), adjacent roll cage diagonals must be the same size as that required for the upright. Motor mount and/or rear end uprights (except rear engine dragster) may be rectangular tubing, 1 3/4-inch x 1-inch x .058-inch (44.5 x 25.4 x 1.5 mm) CM or MS minimum.

Full Bodied Cars

On full bodied car, with driver in driving position, helmet must be in front of main hoop. If helmet is behind or under main hoop, additional tubing same size and thickness as roll cage must be added to protect driver. Main hoop may be laid back or forward but driver must be encapsulated within the required roll cage components.

All cage structures must have in their construction cross bar for seat bracing and as the shoulder harness attachment point; cross bar must be installed no more than 4-inches (102 mm) below, and not above, the driver's shoulders or to side bar. All required rear braces must be installed at a minimum angle of 30-degrees from vertical, and must be welded in. Side bar must pass the driver at a point midway between the shoulder and elbow.

Unless an O.E.M. frame rail is located below and outside of driver's legs (i.e. '55 Chevy, '65 Corvette, etc.) a rocker or sill bar, minimum 1 5/8-inch (41.2 mm) x .083 (2.1 mm) CM or .118 (3.0 mm) MS or 2-inch x 2-inch x .058-inch (50.8 x 50.8 x 1.5 mm) CM or MS rectangular, is mandatory in any car with a modified floor or rocker box within the roll cage uprights (excluding six square feet of transmission maintenance opening). Rocker bar must be installed below and outside of driver's legs, and must tie into the main hoop, the forward hoop, frame, frame extension or side diagonal. Rocker bar may not tie into swing out side bar support. If rocker bar ties into side diagonal more than 5-inches (127 mm) (edge to edge) from forward roll cage support or main hoop, a 1 5/8-inch (41.2 mm) x .083 (2.1 mm) CM or .118 (3.0 mm) MS brace/gusset is mandatory between the diagonal and forward roll cage support or main hoop.

Swing out side bar permitted on O.E.M. full bodied car 7.50 (*4.50) E.T. and slower. The following requirements (a through d) will be enforced on cars certified after 1/1/98, on all cars 1/1/99.

a. 1 5/8-inch (41.2 mm) O.D. x .083-inch (2.1 mm) (CM) or .118-inch (3.0 mm) (MS) minimum. Bolts / pins must be 3/8-inch (9.5 mm) diameter steel, minimum and in double shear at both ends.

b. Male or female clevis(es) permitted. Male clevis must use two minimum 1/8-inch (3.2 mm) thick brackets (CM or MS) welded to each roll cage upright; female must use minimum 1/4-inch (5.4 mm) thick bracket (CM or MS) welded to each roll cage upright. Pins must be within 8-inches (204 mm) of the vertical portion of both the forward and main hoops. A half cup backing device must be welded to the vertical portion of the main hoop (inward side) or the upper end of the swing out bar (outward side), minimum .118-inch (3.0 mm) wall (CM or MS) extending at least 1 5/8-inch (41.2 mm) past the center of the pins. A clevis assembly utilizing a minimum .350-inch (8.90 mm) thick male component and two minimum .175-inch (4.45 mm) thick female components may use a 1/2-inch (12.7 mm) diameter grade 5 bolt, and does not require a half cup backing device.

c. Sliding sleeves of 1 3/8-inch (35 mm) x .083-inch (2.1 mm) CM or .118 (3.0 mm) MS, with minimum 2-inch (51 mm) engagement, are permitted in lieu of the upper pin/cup.

d. All bolt/pin holes in the swing out bar must have at least one hole diameter of material around the outside of the hole.

For all dragsters, funny cars and other cars requiring a funny car or dragster style roll cage, the upper roll cage members must be arranged such that a flat surface passed over any two adjacent members will not contact the driver's helmet while the helmet is held in contact with the inner side of the same roll cage members. If the roll cage members do not satisfy this criteria, head/helmet guards of 3/4 x .049-inch (19.1 x 1.24 mm) round tube or 3/4 (19.1 mm) by .090-inch (2.29 mm) flat strap must be added until the criteria is satisfied.

Effective 1/1/98 for chassis certification, 1/1/99 on all cars requiring a roll cage:

If the O.E.M. firewall has been modified (in excess of 1 square foot (929 cm2) for transmission removal, not including bolted in components) a lower windshield or dash bar of 1 1/4 x .058-inch (32 x 1.5 mm) 4130 chrome moly or 1 1/4 x .118-inch (32 x 3.0 mm) mild steel is mandatory connecting the forward cage supports.

[Chuck]

That is an answer! :rockon:

Good job.

[Mijal]

Copy & Paste huh??
That would`ve taken way to long to type!

[1SLO5.0]

I type fast


really.

[1 BAD 442]

damn darrell that was an awesome answer :bnose:

[1SLO5.0]

I'm here to help.


Let me work on your car before we race, I will help you:D:

[evldoer]

thanks for the info Darrell, I'll put it to good use. I've been waiting for my rule book to come, but it's taking awhile. In the mean time I have a stack of c.m. staring at me wondering why I have not finished it. The main hoop, halo, trunk bars and windsheild bars are in, now I just need to finish the rest.

[1SLO5.0]

no problem.

Where is Leroy? Not Leroy, Wisconsin is it?

[evldoer]

Leroy is 3 miles west of Knowles. Bet that didn't help either? Right next to the horicon marsh.

[1SLO5.0]

Yeah, that's why I was asking. Leroy has like 4 houses and a bar right? Hwy YY runs right through town? I live in North Fond du Lac and work in Horicon. I go thru Leroy every day. I'll have to beep when I go through tomorrow:D:

[Jim]

i have relatives that live in Leroy. Thompson's

[Slow GTO]

Damn, I need a nap after reading all that.:D:

I'll be paying a visit to my chassis shop tomorrow. They are half way through installing my cage and after reading your post I'm not sure it's 100% compliant.

Thanks!

[evldoer]

Darrell, when I'm back from my trip to the super chevy show in Bradenton feel free to stop in. You go right past my house, and yes, it's probably the house you're thinking of!

[evldoer]

Do you spend much time in Toon Town?

[1SLO5.0]

Originally posted by evldoer
Darrell, when I'm back from my trip to the super chevy show in Bradenton feel free to stop in. You go right past my house, and yes, it's probably the house you're thinking of!


Is it the house with the stock car hood hanging on the side of the garage?

[1SLO5.0]

Originally posted by evldoer
Do you spend much time in Toon Town?

Toon Town Tap? Not really. Maybe once every other month.

[evldoer]

No stock car hood. I have a car sitting on my trailer in front of my shop by the road.

[1SLO5.0]

Originally posted by evldoer
No stock car hood. I have a car sitting on my trailer in front of my shop by the road.


east side of the road, just before the hill?

[evldoer]

Yeah, right by that small bridge. I had a 1947 willys panel 4-sale by the road last summer.