Jump to content
HybridZ

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


revlis240

Recommended Posts

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

18gk12.jpg

 

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:

24l7dzt.jpg

 

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

Edited by revlis240
Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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:

RSTRUTBAR1.JPG

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

Edited by revlis240
Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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:

1zg857m.jpg

 

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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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:

1zg857m.jpg

 

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

Link to comment
Share on other sites

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

Link to comment
Share on other sites

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:

etcwtt.jpg

 

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

Link to comment
Share on other sites

  • 2 weeks later...

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 by Hey_You
Link to comment
Share on other sites

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. B)

Link to comment
Share on other sites

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:

 

mcrash09.jpg

 

I'm calling BS on this Internet myth.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...