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Author: Subject: Disaster a Castle Combe Today....
twybrow

posted on 8/9/09 at 07:35 PM Reply With Quote
Disaster a Castle Combe Today....

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.

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l0rd

posted on 8/9/09 at 07:40 PM Reply With Quote


at least you are fine.

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omega0684

posted on 8/9/09 at 07:41 PM Reply With Quote
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]

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Howlor

posted on 8/9/09 at 07:42 PM Reply With Quote
IMO they really need lockwiring if at all possible.

Steve

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aaron bassett

posted on 8/9/09 at 07:43 PM Reply With Quote
got any pics
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franky

posted on 8/9/09 at 07:44 PM Reply With Quote
may I suggest lockwire?
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twybrow

posted on 8/9/09 at 07:48 PM Reply With Quote
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.

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locoboy

posted on 8/9/09 at 07:50 PM Reply With Quote
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.





ATB
Locoboy

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franky

posted on 8/9/09 at 07:53 PM Reply With Quote
forgot to add... glad to hear you made it out ok.
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twybrow

posted on 8/9/09 at 07:53 PM Reply With Quote
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.
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mark chandler

posted on 8/9/09 at 07:56 PM Reply With Quote
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
Rescued attachment Adaptor_bolt.JPG

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Dangle_kt

posted on 8/9/09 at 08:31 PM Reply With Quote


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!

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Russ-Turner

posted on 8/9/09 at 09:11 PM Reply With Quote
At least you sound like you know what you are doing mate so a lesson learned no doubt. Tough break mind.






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smart51

posted on 8/9/09 at 09:19 PM Reply With Quote
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.






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coozer

posted on 8/9/09 at 09:22 PM Reply With Quote
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.





1972 V8 Jago

1980 Z750

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YQUSTA

posted on 8/9/09 at 09:36 PM Reply With Quote
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

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pif

posted on 8/9/09 at 09:54 PM Reply With Quote
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





been a bit of a rush job really, bodged it all together in just 5 1/2 years.

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ashg

posted on 8/9/09 at 10:11 PM Reply With Quote
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.





Anything With Tits or Wheels Will cost you MONEY!!

Haynes Roadster (Finished)
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rick q

posted on 8/9/09 at 11:37 PM Reply With Quote
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 :-


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Mr Whippy

posted on 9/9/09 at 05:56 AM Reply With Quote
^ wow you can see on the shaft where its contacted the hoop and that’s just a normal prop too





Fame is when your old car is plastered all over the internet

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mcerd1

posted on 9/9/09 at 07:48 AM Reply With Quote
quote:
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.

another vote for a circular prop catcher from me

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

oh and make sure it can't fall out the bottom either....

[Edited on 9/9/09 by mcerd1]





-

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rob2005

posted on 9/9/09 at 09:15 AM Reply With Quote
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.





Fortune favours the brave!!

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gixermark

posted on 9/9/09 at 09:15 AM Reply With Quote
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 !!

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nstrug

posted on 9/9/09 at 09:27 AM Reply With Quote
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

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twybrow

posted on 9/9/09 at 10:20 AM Reply With Quote
quote:
Originally posted by gixermark
i always checked the prop/adapter bolts as part of the spanner check before every venture in the bec.


the prop adaptor to prop bolts were fine, it was the large 32mm nut that is contained inside the prop adapter, that must have worked its way loose. I guess punching down through the gears must have put more of a backlash through the system than I would get on the road. Like you, I check all of the accessable bolts very regularly, but this nut is covered by the prop, and is only checkable of you go for a full dismantle before each run!

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