CAMS Tail shaft loop/restraint

takai · Postby **takai** » Sun Mar 25, 2018 9:49 am

In the CAMS manual (Schedule B (c)) it stipulates that

Each automobile must ... be fitted with a device or devices that shall protect any longitudinal propeller shaft from striking the ground in the event of a component failure;

Now the normal bolt in tailshaft loops I have used in the past will likely not work well with the gearbox/diff torsional member. Plus I would like to keep the loop around the entire tail shaft after watching a mate have a failure that punctured the cabin.

What sort of setup do others run for this?

hks_kansei · Postby **hks_kansei** » Sun Mar 25, 2018 10:10 am

If it's an NB8B you could quite easily bolt a loop to the existing mid brace they have.

for an NA6 you could just add some Rivnuts to the floor, or frame rails, and bolt to them instead (design it right and you could make the loop do double duties as a brace)

greenMachine · Postby **greenMachine** » Sun Mar 25, 2018 2:40 pm

Just had my SE logbooked, and admittedly this was not checked. However I looked at this when prepping the car, and as far as I can see the chassis braces, together with my 3in exhaust and the PPF, fully contain the prop shaft. If I get pinged, I will update this post.

:mrgreen:

takai · Postby **takai** » Sun Mar 25, 2018 3:51 pm

Most of the cross tunnel chassis braces would count as a tailshaft retention loop. According to the rule it only has to stop it hitting the tarmac and flipping the car end over like a pole jumping pole.

Now im probably being a bit paranoid about tailshaft explosions... but hey, this does happen:

Nuddy · Postby **Nuddy** » Sun Mar 25, 2018 11:44 pm

If the rear uni fails it's not such a big deal. If the front one fails it can be really nasty on a car where it is not restrained.
I think takai is right that a MX-5 the shaft is well restrained. Certainly on my NC that is the case.

takai · Postby **takai** » Mon Mar 26, 2018 10:37 am

Nuddy wrote:If the rear uni fails it's not such a big deal. If the front one fails it can be really nasty on a car where it is not restrained.
I think takai is right that a MX-5 the shaft is well restrained. Certainly on my NC that is the case.

It is only well restrained downwards, and with the factory braces it would still not be able to be logbooked. Furthermore, if the uni or weld fails at the front then it will likely penetrate the cabin as there is no reinforcement or restraint upwards.

Magpie · Postby **Magpie** » Mon Mar 26, 2018 12:10 pm

I suggested contacting the closest CAMS scrutineer and discuss the requirements.

Each event, like the internet you may get a different answer. For example a 2ltr catch can, is it 2ltrs capacity or is the capacity measured where the uppermost hose(s) attach.

RS2000 · Postby **RS2000** » Mon Mar 26, 2018 12:21 pm

takai wrote:
Nuddy wrote:If the rear uni fails it's not such a big deal. If the front one fails it can be really nasty on a car where it is not restrained.
I think takai is right that a MX-5 the shaft is well restrained. Certainly on my NC that is the case.

It is only well restrained downwards, and with the factory braces it would still not be able to be logbooked.

It only has to be restrained downwards to be log booked.

takai · Postby **takai** » Mon Mar 26, 2018 12:42 pm

RS2000 wrote:
takai wrote:
Nuddy wrote:If the rear uni fails it's not such a big deal. If the front one fails it can be really nasty on a car where it is not restrained.
I think takai is right that a MX-5 the shaft is well restrained. Certainly on my NC that is the case.

It is only well restrained downwards, and with the factory braces it would still not be able to be logbooked.

It only has to be restrained downwards to be log booked.

The factory braces don't prevent a tailshaft hitting the ground if the front uni fails.

Edit: i see my earlier post had a brainfart. I meant to say it is not well restrained downwards.