Did my first trackday in the kit today. Castle Combe arranged through the CSMA - £100 for the day! I was really worried about the track, as it looked very fast with some real orror stories of certain corners.

The day was going great - the car was amongst the fastest out there (apart from the GT3s and a couple of Cateringvans. As I headed onto the main straight I must have been doing close to 100mph, when I felt a slight shudder/vibration for about 2 seconds, then bang bang bang.... This was followed by the sound of someone shaking a bag of cutlery, whilst trying to beat their way out of the transmission tunnel!

I pulled off onto the grass, and waited for the inevitable rescue lorry. No good towing, so had to be loaded onto a flatbed and driven back to the paddock.

I have had a brief chance to look at the damage, and i seem to have got off lightly, as my legs and the chassis are undamaged. The cause was the sprocket/prop adaptor nut worked its way loose, despite 140 lbft, and threadlock.

1 x coolant hose cut
1 x oil way damaged
speedo bracket and magnets damaged
prop front section bent
water pump housing ruined (might have also broken the engine case - wil have to wait and see)
some wiring damage
neutral sensor knackered

And that is without pulling anything out to look.....! It could be worse, as it is the end of the summer, and I had several good Combe sessions today, before the incident. Plus I still have legs, which I appreciate!

So BEC boys in particular, take this as another warning to check those nusts. I changed the nut 2 months ago and cleaned and degreased everything before applyling Loctite, but I guess it wasn't enough.

Picutres to follow tomorrow when I start investigating.... Off to cry now.

at least you are fine.

zx14? ......................................... anyone?

sorry to hear that mate, just sent you a tx as well asking about how it went, then i refreshed the page and saw your post!

[Edited on 8/9/09 by omega0684]

IMO they really need lockwiring if at all possible.

Steve

got any pics

may I suggest lockwire?

I cant face going out there tonight. So pics tomorrow.

I have been discussing new engines with the mrs. I need to see the damage, and get some quotes for engines before figuring if I upgrade. ZX12 and 14 were both discussed with the Mrs, but then I would lose that gorgeous 3-cylinder howl, and constant leaking oil!

I should have found a way of locking the nut - a homemade tab washer or lockwire should have gone on... Lesson learned.

Thank Christ your ok, I have and always will in future build a 'prop catcher' font and rear, just a simple steel ring welded in round the shaft as close to it as you realistically can to still allow service and replacement so that if it does let loose it aint coming flying out the side of the tunnel.
Being curcular too it will 'rub' its self round the inside of it as opposed to battering off the sides of a square box around the shaft.

Would reccommed you do it whilst the engine is out and know your in a little more saftey if it happens again.

forgot to add... glad to hear you made it out ok.

Locoboy - I made one that was boltable onto a welded plate. I didn't get a chance to fit/weld before the SVA, so it is still on my worktop. What a muppet.

When I started fiddling with mine the adaptor fell off last week, bolt sheared. I was lucky as the last time I drive it was 100mph + at Woodbridge, it was just run up the trailer not moved since.

Very lucky




Rescued attachment Adaptor_bolt.JPG

Got me worried now!

Can anyone post a picture of how they would lockwire a prop adapter?

I find lockwiring a bit of an art - which I haven't mastered yet, espesially with a complex stud pattern like a prop adapter!

At least you sound like you know what you are doing mate so a lesson learned no doubt. Tough break mind.

It happened to me on the A47. Luckily I had just pulled away and was doing about 10 MPH. It turned out it was my fault and I had put the nut on backwards so the recess was facing away from the engine. The nut was tightened against the spline not the prop adapter.

The original bike had a lock washer but there's no room for one in the prop adapter. I think mechanical retention is a must though.

I'm sorry to hear about the damage but at 100 MPH it could have been so much worse. What if the rear wheels had locked?

At least working on the car in September is warmer than doing it over the winter.

Locking tab washer over the splines on the adapter. If theres not enough spline showing the adapter is the wrong design. Plus use the original bike nut as it has a slight locjking design but relies on the tab washer for ultimate security.

Just make sure sure your adapter isn't too thick to defeat these measures.

omg mate that sucks big time, glad to hear you are ok the car can be fixed.

I think he did it on purpose to get that zx14 hes been talking about. (joke)

If you need a hand fixing or what ever let me know mate.

Ian

been there and had that, was guttted at the time but felt better when in the following days thought how much worse it could of been. I was doing 50mph but had my 5yr old in the passenger seat.

It'll all fix and be better than before.

propcatchers.. it's the future

pif

i was about to say have you thought about a prop catcher.

its scary that its just that one little bolt holding something so critical.

i read a thread on here the other day about someones prop adapter being slightly off centre causing a slight vibration. if yours is of the same type it would certainly explain the bolt working out.

Can't speak too highly about containing the prop shaft in case it lets go. I'd fitted a new prop shaft in my CEC and was giving it some stick up a lovely mountain road here when it let go.

Huge noise as it thrashed about an inch or so from my hip, but the hoops kept it contained. A relatively simple thing to build, that probably won't ever be needed, but could save you from having a shattered hip :-

^ wow you can see on the shaft where its contacted the hoop and that’s just a normal prop too

quote:

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Originally posted by locoboy
I have and always will in future build a 'prop catcher' font and rear, just a simple steel ring welded in round the shaft as close to it as you realistically can to still allow service and replacement so that if it does let loose it aint coming flying out the side of the tunnel.
Being curcular too it will 'rub' its self round the inside of it as opposed to battering off the sides of a square box around the shaft.

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Hoops fitted to mine by the preveous owner, I'd cac myself if I didn't have them. Simple but limb saving I'd say.

I'm off to do my monthly spanner check.

i always checked the prop/adapter bolts as part of the spanner check before every venture in the bec.

also a vote for the prop catchers - i had a trailing arm failure in mine - which allowed the diff/axle to move side ways.. and tore the bolts out between diff and prop.. thankfully my lefs survived.. but could have been worse !!

Can I maybe suggest people look at the Dax system?

Rather than use a prop adapter, this uses the original sprocket and a pin drive mechanism - basically the end of the prop has 16 pins that slot over the original sprocket. This acts almost like a CV joint and, combined with two prop catch hoops, looks like a more secure solution.

Nick

quote:

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Originally posted by gixermark
i always checked the prop/adapter bolts as part of the spanner check before every venture in the bec.

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quote:

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if you make each loop in 2 bits bolted together you should be able to have it a very close to the prop without afecting your ability to remove or service it

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