How do you bolt a harness to an early 71 car?

[revlis240]

See the image below. The arrow points to the reinforced thick bolt hole where the seatbelt used to mount.

 

The 1973 parts car I had used to have a lap belt cut out where the red square is in the pic, and in that hole the

seatbelt used to reside. The 71 chassis im restoring doesnt even have a hole for that, and so far i can tell

only has that 1 hole. I was planning to use a 4 point harness (or do I get a 5 point? I will NOT be racing/tracking this car).

With that 1 hole, I dont know how to get the lap part of the belt to mount. I dont have a welder.

 

The shoulder part I was going to mount to the rear strut tower brace.

 

Suggestions? Thanks!

 

 

EDIT:

I think I answered my own question. Upon further evaluation I found this threaded hole on both sides:

 

And Im guessing that was where the factory lap belt went anyway!

Edited November 29, 2010 by revlis240

[JMortensen]

The other hole for the lap belt is on the rocker panel, not the floor. If you're going to use a 5 point you'll need to reinforce the floor. I think some belts come with really big washers. Not sure if that is considered sufficient or if you could have the washers welded to make it sufficient. I wouldn't use a typical MSA style strut tower brace for my shoulder belts, but the main thing is that the angle has to be right. If the mount behind the seat is too low or too high, it could be trouble.

[revlis240]

The other hole for the lap belt is on the rocker panel, not the floor. If you're going to use a 5 point you'll need to reinforce the floor. I think some belts come with really big washers. Not sure if that is considered sufficient or if you could have the washers welded to make it sufficient. I wouldn't use a typical MSA style strut tower brace for my shoulder belts, but the main thing is that the angle has to be right. If the mount behind the seat is too low or too high, it could be trouble.

 

Right,

I read that the angle has to be within 20 degrees. Now the PDK strut mount shown here:

Seems to be within the reasonable range. Right? For just occasional weekend driving and no racing/events will a 4pt harness suffice?

Edited November 29, 2010 by revlis240

[JMortensen]

I think the spec on the angle is something like 5-10 degrees. I know John Coffey has linked to Schroth's "how to" page a billion times. Might try searching for that info here or on google.

 

PDK brace is better than most. I don't know if there is a rule about how big the fasteners have to be, tubing sizes, etc, but I think I'd feel comfortable with the PDK. I ran a 4 pt for autox and track days. Lots of people will tell you if you're going to run a 4 pt you should run the 5 point, but I had seats with no sub strap hole and no welder to make a mount. Never had any problems, but I also never got in an accident. I hooked up the 4 pt behind the seat and ran the stock belt when i was driving on the street. The 4 pt is a real PITA on the street you can't hardly reach anything, it's damn near impossible to roll down the window, and I slammed the door on the lap belt more than once getting out of the car in the pits.

[revlis240]

Only reason Im considering a 4pt is because I dont think my '71 even has a shoulder mount, only a lap belt which i feel is rather useless. Is there an alternative in the middle which ive missed?

 

This diagram is from the Schroth booklet:

 

Seems to me that everyone has their shoulder harness installed incorrectly, as almost every one ive seen is parallel and not crossed over as shown in the diagram. Perhaps the problem is avoided with a Y shaped shoulder part as shown in the PDK picture.

[rturbo 930]

There is a third bolt hole above the quarter window on my early '71. Yours might have it as well, but I don't know if 3pt seat belts were standard on the early cars.

 

You might give this a thought: http://www.thezstore.com/page/TZS/PROD/SIC03D/40-7490

Edited November 29, 2010 by rturbo 930

[johnc]

Use the mounting style that comes with the instructions for the harness you purchase. The crossed shoulder harness mounting is for non-race seats that don't have the holes in the seat back.

[JMortensen]

There is a third bolt hole above the quarter window on my early '71. Yours might have it as well, but I don't know if 3pt seat belts were standard on the early cars.

 

You might give this a thought: http://www.thezstore.../SIC03D/40-7490

3 pt belts were standard. That seatbelt from MSA looks very familiar. A buddy of mine put retractable belts in his 510 that looked just like that. I know they came out of a VW, not sure which model, want to say it was a van.

[zgeezer]

Only reason Im considering a 4pt is because I dont think my '71 even has a shoulder mount, only a lap belt which i feel is rather useless. Is there an alternative in the middle which ive missed?

 

This diagram is from the Schroth booklet:

 

Seems to me that everyone has their shoulder harness installed incorrectly, as almost every one ive seen is parallel and not crossed over as shown in the diagram. Perhaps the problem is avoided with a Y shaped shoulder part as shown in the PDK picture.

 

Not sure what you really mean by a middle ground; but, I opted out for the later 280z 3 point lap belt and "over the shoulder" shoulder belt. Not a race quality harness, but, it has inertia reels and is much more convenient than the original lap/shoulder belt of the early model. Did require light welding. Look at my album (zgeezer) on this site for photos.

 

G

[revlis240]

There is a third bolt hole above the quarter window on my early '71. Yours might have it as well, but I don't know if 3pt seat belts were standard on the early cars.

 

You might give this a thought: http://www.thezstore.com/page/TZS/PROD/SIC03D/40-7490

 

Nice! I referenced the pic and it does have the holes in above the window. Badass, I will order those belts unless I can find a cheaper junk yard solution! Thanks

[AlexPie]

pretty sure the 3 point system standard its just the over the shoulder part 'clipped' into the lap belt part

 

if that makes any bit of sense

[AlexPie]

pretty sure the 3 point system standard its just the over the shoulder part 'clipped' into the lap belt part

 

if that makes any bit of sense

[revlis240]

I bought a nice 3 point seatbelt thats identical to the Z store one, off a member here. Question, are you not supposed to torque down this bolt? Doing so would crack the trim piece under it:

Edited December 6, 2010 by revlis240

[johnc]

I bought a nice 3 point seatbelt thats identical to the Z store one, off a member here. Question, are you not supposed to torque down this bolt? Doing so would crack the trim piece under it:

 

There should be a 1/2" spacer that butts against the C-pillar sheet metal and spaces the tab out from the trim.

[rturbo 930]

Don't suppose you guys have the specs of that bolt on hand? I'm missing one.

[revlis240]

hrmm, ill have to custom make that spacer then, mine are long gone.

 

rturbo, I can only tell you that its a 16mm or 5/8" bolt head. The pitch and what not I dont have on hand sorry.

[Hey_You]

Not to be a buster, but unless your car is caged, this would be the only harness I would suggest Schroth

Reason being in case of a roll-over a standard harness will not allow your body to move forward resulting in you being crushed instead of bent over.

Edited December 17, 2010 by Hey_You

[ModernS30]

Not to be a buster, but unless your car is caged, this would be the only harness I would suggest Schroth

Reason being in case of a roll-over a standard harness will not allow your body to move forward resulting in you being crushed instead of bent over.

 

Without a roll bar I wouldn't recommend a harness. I don't see the purpose in a harness that isn't properly fitted anyway. A harness with to much extra length or that is bolted down to the floor (Shoulder straps) is doing more harm than good. Yes, they hold you in better, if you are doing racing where you could possibly flip your car over, then you may want to just put a roll bar in anyway.

[johnc]

Not to be a buster, but unless your car is caged, this would be the only harness I would suggest Schroth

Reason being in case of a roll-over a standard harness will not allow your body to move forward resulting in you being crushed instead of bent over.

 

I see people post this on the Internet all the time yet, in all my years of racing, working the corners, and Tech, I have never seen anyone injured in a wreck in this way. I don't think its ever happened. Even this extreme example where the roll cage structure failed and the roof completely collapsed resulted in only minor injuries to the driver and passenger:

 

 

I'm calling BS on this Internet myth.