Prop shaft restraint!

[Franky boy]

Hi all,

Newbie here! I'm entering my first sprint in a couple of weeks, albeit in my road car, jag xj6, I see that the blue book states that front engined cars need a prop shaft restraint, do i need one in a road going proddy class? if so, how to I make one?

I'd hate to turn up and fail scrutineering, so any advice welcome.

Cheers all, and look forward to getting involved.

Frank

[jagracer]

In ten years of racing it's never been mentioned at scrutineering and I've never heard of anyone being pulled about it. Also you have an XJ6 which has a thick steel tunnel which would act as a restraint if it breaks.

[Franky boy]

I can understand it in a westie/kit to prevent damage in the cockpit, but thought it seemed strange in a Jaguar, Many thanks for the advice, bring on the first time out! can't wait

[jagracer]

I may be wrong on this but I believe it's a recommendation not a requirement, I don't have the Blue book to hand.

[Zumbruk]

I've been sprinting for 6 years (in a TVR) and no-one's ever mentioned it. I wouldn't worry about it.

[Franky boy]

Cheers for the info

[no17]

I would seriously suggest you get one fitted. A few years back I was testing my newly built classic Jaguar saloon racer at Mallory (no restraint fitted at the time), when the propshaft sheared whilst accelerating hard out of Gerrards.
The prop dug into the tarmac and the car was catapulted at least three feet into the air. If it had happened when racing
I would have taken several cars out as well as myself.
May I add, this wasn't some forty year old knackered prop but
a new professionally built/fitted unit

[jagracer]

no17 said:

I would seriously suggest you get one fitted. A few years back I was testing my newly built classic Jaguar saloon racer at Mallory (no restraint fitted at the time), when the propshaft sheared whilst accelerating hard out of Gerrards.
The prop dug into the tarmac and the car was catapulted at least three feet into the air. If it had happened when racing
I would have taken several cars out as well as myself.
May I add, this wasn't some forty year old knackered prop but
a new professionally built/fitted unit

I hope you changed your propshaft builder after that.

[no17]

I hasten to add this wasn't the first time I've experienced a
broken prop in racing conditions. Again a test day this time at Castle Coombe when the two part prop broke at the centre bearing. The 2 x prop restraints (just simple half loops bolted to the floor), did their designed job.

[andy rob]

id not race a rwd car without one, the prop snapping can make a real mess of the car

[procomp]

Hi

propshaft restraint are supposed to be compulsory under MSA regulations.
They certainly help keep the prop from injuring a driver but are also there to stop the car from becoming airborne if it should be the front joint that gives up. seen more than a few Escorts Chevette's Etc flying at a 10Ft altitude due to prop joint failures on airfield stages.

Chances of a scrutineer checking for one fitted. 0%

Cheers Matt

[jagracer]

To be honest when the original post came on I was more thinking of damage to the driver's legs from an errant propshaft or even a flywheel. My car has a ladder frame chassis with cross bars that would stop a prop hitting the ground but not much in the way of sideways protection apart from more rails and diagonal tubes, whether these would stop anything is another question.

[Franky boy]

Hi all,

Apart from spilling a can of coke over my laptop and having to deal with sticky keys, all is going well with getting the car ready.

Thanks for all the info.

I've had her on a lift and had a good nosy around underneath.

Being a production car, the transmission tunnel is substantial, so I am happy that in the event of a propshaft failure the shaft can not break through into the interior. As far as dropping out on to the road surface, there appears to be an existing bracket about 50mm in from each end of the prop, and the exhaust/cats run directly under the prop.

I have done a few searches on tinternet, and all references seem to be about hoops or steel transmission tunnel to prevent the prop from causing damage/injury to the interior or driver/passenger, so think everything is good to go.

Fluids changed/topped up, new pads all round, filters changed and timing strut made, so roll on next weekend, am I taking it to seriously! (to secure a last place, lol, but I'll have the biggest smile)

Cheers

Frank

Edited by Franky boy on Saturday 21st August 12:18

[carl_w]

Didn't they test prop shaft failure on Mythbusters? Might be worth scouring Youtube.

[Franky boy]

I saw it, ages to get the prop to drop into the required hole in the road to get the "lift" and then not a great amount of it, did make a mess of the rear end though. Still, worth thinking about.

[Al Weyman]

Its mandatory in SCCA racing in the US, funny enough one of the guys I race against lined up on the grid Saturday and dropped the clutch in his XJ12 and the prop snapped so it does happen!