Driveshaft safety hoop construction

[mrsix]

Hi, I have purchased some commercially made driveshaft safety hoops. The bolt together versions (2 x curved "U" sections, 2 x "L" sections). They will need some tweaking to get them to bolt up to the floor profile, and the smaller size of the transmission tunnel. I would like to fit them with as little clearance as possible, between the safety hoops and the floor/ trans tunnel of the car.

Is it ok to bend and/or twist, the "L" brackets, to match the car's floor profile, where they will be mounted?

Can I weld the mounting bolts to the top side floor plates, to make them "captive"? (As long as it is done to a suitable standard).

Can the upper half of the safety hoop, be permanently welded to the "L" sections  (As long as it is done to a suitable standard), instead of having it bolted to them? The bottom "U" would still be bolted on, to aid in driveshaft removal, in future.

cheers

[Chris]

Oct 7, 2023 13:01:55 GMT 12 mrsix said:

Hi, I have purchased some commercially made driveshaft safety hoops. The bolt together versions (2 x curved "U" sections, 2 x "L" sections). They will need some tweaking to get them to bolt up to the floor profile, and the smaller size of the transmission tunnel. I would like to fit them with as little clearance as possible, between the safety hoops and the floor/ trans tunnel of the car.

Is it ok to bend and/or twist, the "L" brackets, to match the car's floor profile, where they will be mounted?

Can I weld the mounting bolts to the top side floor plates, to make them "captive"? (As long as it is done to a suitable standard).

Can the upper half of the safety hoop, be permanently welded to the "L" sections  (As long as it is done to a suitable standard), instead of having it bolted to them? The bottom "U" would still be bolted on, to aid in driveshaft removal, in future.

cheers

Is it ok to bend and/or twist, the "L" brackets, to match the car's floor profile, where they will be mounted?
Yes

Can I weld the mounting bolts to the top side floor plates, to make them "captive"? (As long as it is done to a suitable standard).
Yes

Can the upper half of the safety hoop, be permanently welded to the "L" sections (As long as it is done to a suitable standard), instead of having it bolted to them? The bottom "U" would still be bolted on, to aid in driveshaft removal, in future.
Yes

Regards

Chris

[mrsix]

Hi, I have another query on the safety hoops please. This is about where they can be bolted to the vehicle floor.

Can the attachment points (where the bolts go through the floor), be forward of the hoop, and the centre of the universal joint? The floor structure (triple layer enclosed seat platform /floor) prevents access, to attachment points, in the area of the floor adjacent to the hoop position. The closest accessible area is 250 mm forward, and 200 mm to each side, of the centreline of the hoop. Which will also be forward of the centre of the universal joint. Going backwards from the hoop position, is more than 250 mm, to an accessible area.

Reading the NZ Car Construction Manual, 9.22, 9.23, 9.24, 9.25, 9.26. It doesn't seem to rule out, having the mounting points, ahead of the hoop itself. And mentions the position of the hoop, being no more than 250 mm rearward of the front driveshaft joint pivot centre.

9.25 Drive-shaft safety-loop attachment


9.25.1

A drive-shaft safety-loop fitted to a low volume vehicle must be

attached to the vehicle structure:

(a) in not less than two places; and

(b) as closely to the ‘loop' section of the drive-shaft safety-loop

as practicably achievable (see Diagrams 7.1 and 7.2).

Am I misunderstanding, or have I missed something?  Am I on the right track? 
The vehicle being engine / transmission swapped, is in very good condition, with a long family history. So trying to get this right first time. And avoid having to modify any of the floor structure, except for the inner plate securing holes. 

cheers

[Chris]

Oct 25, 2023 12:26:20 GMT 12 mrsix said:

Hi, I have another query on the safety hoops please. This is about where they can be bolted to the vehicle floor.

Can the attachment points (where the bolts go through the floor), be forward of the hoop, and the centre of the universal joint? The floor structure (triple layer enclosed seat platform /floor) prevents access, to attachment points, in the area of the floor adjacent to the hoop position. The closest accessible area is 250 mm forward, and 200 mm to each side, of the centreline of the hoop. Which will also be forward of the centre of the universal joint. Going backwards from the hoop position, is more than 250 mm, to an accessible area.

Reading the NZ Car Construction Manual, 9.22, 9.23, 9.24, 9.25, 9.26. It doesn't seem to rule out, having the mounting points, ahead of the hoop itself. And mentions the position of the hoop, being no more than 250 mm rearward of the front driveshaft joint pivot centre.

9.25 Drive-shaft safety-loop attachment


9.25.1

A drive-shaft safety-loop fitted to a low volume vehicle must be

attached to the vehicle structure:

(a) in not less than two places; and

(b) as closely to the ‘loop' section of the drive-shaft safety-loop

as practicably achievable (see Diagrams 7.1 and 7.2).

Am I misunderstanding, or have I missed something?  Am I on the right track? 
The vehicle being engine / transmission swapped, is in very good condition, with a long family history. So trying to get this right first time. And avoid having to modify any of the floor structure, except for the inner plate securing holes. 

cheers

Without being able to see the vehicle, this is a very difficult question to answer, this is best answered by taking the vehicle to your certifier and discussing options with them.

Regards

Chris

[mrsix]

Thanks Chris.

Unfortunately, the certifier is not just down the road. I have emailed them, photos and a description and I'm awaiting a 2nd reply. The first reply wasn't clear. Getting them on the phone can be difficult.

I'm not trying to break the rules, just trying to get it right. And not mess with the structure of the car, by cutting access holes in the interior floor.

Can I provide any other information, to get an indication of if it is ok, a maybe, or no way? I did try to post a pic, but have nothing under the max attachment size. 
Not looking for 100 % approval, just guidance.
cheers

[Chris]

Oct 25, 2023 14:00:44 GMT 12 mrsix said:

Thanks Chris.

Unfortunately, the certifier is not just down the road. I have emailed them, photos and a description and I'm awaiting a 2nd reply. The first reply wasn't clear. Getting them on the phone can be difficult.

I'm not trying to break the rules, just trying to get it right. And not mess with the structure of the car, by cutting access holes in the interior floor.

Can I provide any other information, to get an indication of if it is ok, a maybe, or no way? I did try to post a pic, but have nothing under the max attachment size. 
Not looking for 100 % approval, just guidance.
cheers

I doubt if a certifier is unable to provide a clear answer from photos and a description then I would be able to do any better. Often with these trickier ones it requires eyeballs on the parts to give a clear answer.