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I am going to install my new harness pretty soon and had a question about the mounting points. I was wondering if I could use the same hole and bolt that the original seat belt was mounted? I don't see why it wouldn't be as safe. I would think a 3 point system would put more stress in a crash on that point then a 5 or 6 point system. Has anyone tried it before, and more importantly has it passed tech?

So if it won't do, how did other people mount there harnesses? If I mount it to sheet metal do the mounting plates have to go behind the metal or can they be welded. In other words can you weld the bolt to the plate, drill a hole in the sheet metal larger then the bolt, then weld around the edges of the mounting plate?

Basically how did everyone else mount their belts?
 

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If you mean using them for the lap belts of your harness, go right ahead. They are plenty strong and well engineered by the manufacturer.

Of course if you drastically relocated your seats, you may have to see if they give the correct angles recommended in the rule book.
 

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Thats the only problem I can see, you just have to make sure the mounting points line up with what is acceptable in the rulebook. When I mounted my belts I welded 2.5" by 2.5" by 3/16" plates to the floor with short tabs welded to them that the belts bolted too. The tech inspectors thought that was perfectly fine. The stock location was too far to the side of the seat to work.
The only other thing I can say is pay close attention to how the manufacturer and the rule book say to mount the belts, because they won't function properly otherwise. Don't want anyone out there in rally land pulling a Dale Earnhardt.




Nick Polimeni
'71 Volvo 142E (daily driver/RallyCross)
'71 Volvo 145S G2/historic car, when I find time and money to actually build it, or failing that, someone elses money
Editor, Blue Mountain Region, SCCA
[email protected]
www.bmr-scca.org
 

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>I am going to install my new harness pretty soon and had a
>question about the mounting points. I was wondering if I
>could use the same hole and bolt that the original seat belt
>was mounted? I don't see why it wouldn't be as safe. I
>would think a 3 point system would put more stress in a
>crash on that point then a 5 or 6 point system. Has anyone
>tried it before, and more importantly has it passed tech?
>
Like the other guys said, make sure your belt angles will be okay. The belt hardware is the same oddball 7/16-20 thread as standard seatbelt bolts for a reason.

>So if it won't do, how did other people mount there
>harnesses? If I mount it to sheet metal do the mounting
>plates have to go behind the metal or can they be welded.
>In other words can you weld the bolt to the plate, drill a
>hole in the sheet metal larger then the bolt, then weld
>around the edges of the mounting plate?
>
Rather than weld a bolt to your plate; weld a nut on the back of the plate so you have a choice of using a bolt-in belt or eyebolt with a snap-in belt. If you have to put your mounts on the floor try to put them as near to the bends of the exhaust tunnel and rocker box as possible.
 

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The eyebolts refered to are the solid type, ususally forged or cast as one piece, and accomodate a clip-in belt end; these eyebolts can be bought at the same place you buy the belts. The hardware store types are not OK as they can open, unless you weld the end back onto the main threaded shaft. Even then, getting the right sizing is a problem, so it's not a good route to go.

Make the backing plates 3" x 3" or larger; .125" thick minimum, .186" preferred. (Thought the latter thickness is not as easy to lap weld onto thin sheet metal.)

Mark Bowers
 

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Using the stock mounts passes tech all the time. In any belt mount, watch for any sharp edges where the belt passes over the edges of the seat; this is normally no problemo on a race seat, but you have to watch it on stock seats.

As for your shoulder harness, a lot of folks are putting a shallow U shaped bar (with the bends in the horizontal plane) behind the seats, and with the ends welded across the main hoop, just below shoulder height. This is a good place to install shoulder belts, using a wrap arounf the bar. It provides seat back bracing too. (Required with stock seats.) A similar alternate is a bar across the rear struts. (I personally do not like the latter because of the long length of the shoulder harness to this far rear bar allows more belt stretch in hard frontal impact.)

And pay attention to the prescribed seat belt looping through the wrap plates/secondary adjusters (or whatever they are called); this is shown clearly in the rules.

Mark B.
 
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