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Should have fitted a prop catcher !
NigeEss - 12/11/13 at 12:49 AM

Fortunately it stayed within the confines of the tunnel.




[img][/img]

dhutch - 12/11/13 at 06:33 AM

Cant see the video at work, but I keep meaning to fit one of these!

kj - 12/11/13 at 07:10 AM

a bit of a shock eh

daniel mason - 12/11/13 at 07:12 AM

i wondered what had gone on when i saw you pulled over!

adithorp - 12/11/13 at 07:41 AM

Didn't realise thats what happened. It could have been a lot worse but would have been better with a catcher. What did it batter?

iank - 12/11/13 at 08:00 AM

Easy to lose a leg or worse. Glad you got away with it!

jamesbond007ltk - 12/11/13 at 08:07 AM

Perhaps very lucky it was not far more catastrophic. Did it fail front or back?

Can I ask, who made your prop?


Sorry in advance for the hi-jack:

As a general question has there ever been any patterns identified with prop failures such as gearbox/diff combinations, alignment angles, prop manufacturer etc? When i first built my car I made my own from a sierra prop. It was only ever meant to be temporary, in fact just for testing, but ended up doing about 2,000 miles before taking the car off the road for other reasons. Other than a noticeable imbalance at high speed I never had any problems with it.

I have always told myself I would replace it and now my rebuild is nearing completion I have been looking at my options. I am just rather concerned that professionally manufactured props seem to fail all too often.

Rich

Jon Ison - 12/11/13 at 08:26 AM

Sound doesn't do that justice, I was in the garage at the time my first thoughts was someone was going down the pit straight either scraping the wall or upside down, it was very loud.

I had one fail at Cadwell top of the mountain, fortunately have a prop catcher in the tunnel, anyone thinking about it get one, flailing prop shafts have no mercy.

pif - 12/11/13 at 08:36 AM

the sound on that video reminded me of mine coming off. Horrible sound.

Lucky to get away with no injury and damage to car doesnt look to bad.

You will soon be back on the road.

DavidW - 12/11/13 at 08:46 AM

That reminds me that I was going to do this over the winter. Thanks for sharing and I'm glad you're ok.

Now to find the threads and work out where I put the catcher - front or back?

David

loggyboy - 12/11/13 at 08:47 AM

quote:
Originally posted by jamesbond007ltk
Perhaps very lucky it was not far more catastrophic. Did it fail front or back?


Front by the looks of the damage adjacent to the gearbox output.

loggyboy - 12/11/13 at 08:49 AM

quote:
Originally posted by DavidW
That reminds me that I was going to do this over the winter. Thanks for sharing and I'm glad you're ok.

Now to find the threads and work out where I put the catcher - front or back?

David

No reason not to do both IMO - I have.

Lots of search results - linky

Dick Axtell - 12/11/13 at 09:52 AM

quote:
Originally posted by NigeEss
Fortunately it stayed within the confines of the tunnel.

[img][/img]


NigeEss, you appear to be one lucky chap!! Judging from your pic, it seems to be a front end failure of ur p/shaft. Do you have a more detailed pic of the failed area? What type of coupling/adapter did you fit between shaft and bike 'box?

Re-watching your vid, from the sound I'd guess that you weren't anywhere near full chat. If you had been, damage might have been worse.

[Edited on 12/11/13 by Dick Axtell]

Peteff - 12/11/13 at 09:57 AM

If it fails at the front it will flail till the wheels stop turning at whatever speed you are doing whereas the rear will be driven by the engine on tickover if you lift off.

iank - 12/11/13 at 10:09 AM

If the front fails there is a small chance the prop can dig into the road ripping the rear axle/diff off and throwing the car violently in a random direction. Fit both.

Slimy38 - 12/11/13 at 10:10 AM

quote:
Originally posted by Peteff
... whereas the rear will be driven by the engine on tickover if you lift off.


Or if you have enough wits about you, you could dip the clutch and it would stop completely?

I'd say if you can only fit one, a front one would be the best choice.

mcerd1 - 12/11/13 at 10:38 AM

quote:
Originally posted by Slimy38
quote:
Originally posted by Peteff
... whereas the rear will be driven by the engine on tickover if you lift off.


Or if you have enough wits about you, you could dip the clutch and it would stop completely?

I'd say if you can only fit one, a front one would be the best choice.


^^ your not wrong - but how long have you really got to get your foot on the clutch ?

...better to find a way to fit one at both ends

[Edited on 12/11/2013 by mcerd1]

unijacko67 - 12/11/13 at 10:55 AM

You were certainly lucky, I need to fit a prop catcher, but it keeps getting pushed to the back of the list along with the towing eye's and fire extinguisher. Was good to meet you at Oulton.

pif - 12/11/13 at 10:59 AM

Mine came off at the front and smashed the clutch cylinder so no dipping that although it was irrlevant as it came off at the front. BTW it wiped out the Brake master cylinder too so no foot brake either.

IIRC it took 2 water pipes, fuel line, chunk of block and all the engine bay / dash wiring too.

HO HO, that was a day to remember.

But it didnt take me or my 7 year old sat in passenger seat............

iank - 12/11/13 at 12:17 PM

quote:
Originally posted by mcerd1
quote:
Originally posted by Slimy38
quote:
Originally posted by Peteff
... whereas the rear will be driven by the engine on tickover if you lift off.


Or if you have enough wits about you, you could dip the clutch and it would stop completely?

I'd say if you can only fit one, a front one would be the best choice.


^^ your not wrong - but how long have you really got to get your foot on the clutch ?

...better to find a way to fit one at both ends

[Edited on 12/11/2013 by mcerd1]


And can you keep it pressed with a prop flailing its way through your left leg

Johneturbo - 12/11/13 at 12:55 PM

Very scary and a horible sound

i had mine snap at the front as i accelerated from 40 zone to 60 zone thankfuly no injurys to me or lisa

but the car was a right off as it hit a fuel line and burt to the ground

mine snapped at the front UJ nuckle

[Edited on 12/11/13 by Johneturbo]

daveb666 - 12/11/13 at 01:47 PM

Being new to kit cars I'd never really heard of this problem until now.

Has anyone used the ones that DAnST engineering sell?

http://www.locostbuilders.co.uk/viewthread.php?tid=156382

Seem cheap for the potential damage that could be caused..

Not Anumber - 12/11/13 at 03:01 PM

I had one go on a Pilgrim Sumo Cobra replica once at the rear UJ. The thing hit the road and lifted the back of the car into the air slightly- presumably this would have been rather worse if i was doing 70 rather than just 30mph at the time.

I put that experience down to the odd design of that car, the prop ran at wild angle to an off centre diff. Presumably in most kit though theres no reason why a prop should fail any more frequently than in any other rwd car.

loggyboy - 12/11/13 at 03:19 PM

quote:
Originally posted by Not Anumber
Presumably in most kit though theres no reason why a prop should fail any more frequently than in any other rwd car.


Except most kit props are modified and most 'other' rwd will have 'manufactured' props. Not that a good one of either is better than the other, just more chance of having a weakness in a modified one.

Not Anumber - 12/11/13 at 03:32 PM

I could see that would be the case if kit car prop shafts tended to fail on the welds where they had been cut and shut but they always seem to go on the UJs though.

Is it to do with the joints having to handle significantly more power than they were built to withstand and is there any real solution ?

dave r - 12/11/13 at 04:32 PM

this is also on my to do list....... what sort of clearance should i allow to the prop ?

mcerd1 - 12/11/13 at 04:50 PM

quote:
Originally posted by daveb666
Has anyone used the ones that DAnST engineering sell?

http://www.locostbuilders.co.uk/viewthread.php?tid=156382

Seem cheap for the potential damage that could be caused..


I've not herd of any prop failures with anyone who's fitted one of Dan's catchers yet... - but if you search for it you'll find the old thread with the evolution of its design and some of the first customers for one


the trick is to have a fairly close fitting catcher (round inside for preference) to limit the how far the prop can fall - if it can't more far its not actually that dangerous

the danger comes when its allowed to move enough that it can start whipping around


forget the fancy new joint they are selling (i.e. skip to about 6min) but this gives you a pretty good idea of the problem:



[Edited on 12/11/2013 by mcerd1]

loggyboy - 12/11/13 at 04:58 PM

quote:
Originally posted by dave r
this is also on my to do list....... what sort of clearance should i allow to the prop ?


On an IRS set up with a fixed diff and box you could get away with less than 10mm.
With a live axle you would obviously need to allow for more at the diff end.

Heres mine for a an IRS Striker



Not Anumber - 12/11/13 at 05:18 PM

A prop catcher is one thing but what can be done to prevent failure. I dont see prop catchers having to be fitted to rwd road cars and i dont see many rwd road cars suffering from prop failures.

Surely it's better to stamp out the disease rather than the minimise the symptoms ?

NigeEss - 12/11/13 at 05:49 PM

Ok, to answer a few questions.

1- It failed at the front.
2- It was a temporary prop with a rubber coupling which I do not like, but it was use that or miss the day.
3- I made it, but it wasn't my welding that failed but the rubber coupling. It's the seventh prop I've made over the years and
the first to ever let go.
4- It dented the tunnel tubes but only the lower ones, the upper ones escaped as the tunnel cover took the beating.
Punched a hole in the floor, you can see the newspaper undernbeath in the photo.
5- The wiring to the fuel pumps managed to get wrapped round the prop and pulled out from both ends.


But, hey, no damage to me , the car is easily fixed.

mcerd1 - 13/11/13 at 09:01 AM

quote:
Originally posted by Not Anumber
I dont see prop catchers having to be fitted to rwd road cars and i dont see many rwd road cars suffering from prop failures.

you'd probably see more prop failures on tin-tops if everyone took them to the track for a good thrash every now and then

prop catchers aren't needed as much on tin-tops mainly because your less likely to get injured when they let go (i.e. your not sitting right next to the thing with only a thin sheet of alloy and a few tubes to protect you


its more to do with the consequences of a failure than it is to do with the likelihood of failure

this says it all really
quote:
Originally posted by Johneturbo
i had mine snap at the front as i accelerated from 40 zone to 60 zone thankfuly no injurys to me or lisa

but the car was a right off as it hit a fuel line and burt to the ground







home made / modified shafts that haven't been balanced will have more vibration and that could shorten there life, but even a brand new manufactured prop needs to be checked when the car is serviced to look for signs of damage or even just worn bearings or a lack of grease....


but that wouldn't help much in this case as it was the rubber coupling thingy...



[Edited on 13/11/2013 by mcerd1]

[Edited on 13/11/2013 by mcerd1]

loggyboy - 13/11/13 at 09:25 AM

quote:
Originally posted by Not Anumber
A prop catcher is one thing but what can be done to prevent failure. I dont see prop catchers having to be fitted to rwd road cars and i dont see many rwd road cars suffering from prop failures.

Surely it's better to stamp out the disease rather than the minimise the symptoms ?


MSA requires them. Which as mentioned already, points to the 'using them in anger'

40inches - 13/11/13 at 09:54 AM

There is the other type of failure, caused by imbalance/thin tubing apparently. This looks like ERW tubing.


The prop can start to whip and eventually fails http://www.locostbuilders.co.uk/viewthread.php?tid=122181
Prop catchers can also stop the diff falling out, when the diff mounts fail


Now that was a brown trouser moment

[Edited on 13-11-13 by 40inches]

matt_claydon - 13/11/13 at 02:29 PM

I should imagine the failures seen in many kits and modified cars is due to builders (and suppliers) not understanding the need for the transmission output and diff input flanges to be (at least almost) perfectly parallel, not having the means to set this accurately, or not making the shaft with the couplings correctly phased.

Fitting the engine under the bonnet or dealing with other engine mounting issues normall takes priority over a correctly angled gearbox output. The result of this is cyclic loading of the shaft (leading to fatigue) and vibration which may or may not be noticeable to the driver.

[Edited on 13/11/13 by matt_claydon]

Johneturbo - 13/11/13 at 05:50 PM

quote:
Originally posted by mcerd1
quote:
Originally posted by Not Anumber
I dont see prop catchers having to be fitted to rwd road cars and i dont see many rwd road cars suffering from prop failures.

you'd probably see more prop failures on tin-tops if everyone took them to the track for a good thrash every now and then

prop catchers aren't needed as much on tin-tops mainly because your less likely to get injured when they let go (i.e. your not sitting right next to the thing with only a thin sheet of alloy and a few tubes to protect you


its more to do with the consequences of a failure than it is to do with the likelihood of failure

this says it all really
quote:
Originally posted by Johneturbo
i had mine snap at the front as i accelerated from 40 zone to 60 zone thankfuly no injurys to me or lisa

but the car was a right off as it hit a fuel line and burt to the ground







home made / modified shafts that haven't been balanced will have more vibration and that could shorten there life, but even a brand new manufactured prop needs to be checked when the car is serviced to look for signs of damage or even just worn bearings or a lack of grease....


but that wouldn't help much in this case as it was the rubber coupling thingy...



[Edited on 13/11/2013 by mcerd1]

[Edited on 13/11/2013 by mcerd1]


mine was a brand new 2 piece prop made for the job with a quaif reverse box

adithorp - 13/11/13 at 07:10 PM

This is the rear catcher on my Fury...



I've similar one at the front but with different mounting points.

CosKev3 - 29/11/13 at 09:30 AM

quote:
Originally posted by Not Anumber
A prop catcher is one thing but what can be done to prevent failure. I dont see prop catchers having to be fitted to rwd road cars and i dont see many rwd road cars suffering from prop failures.

Surely it's better to stamp out the disease rather than the minimise the symptoms ?


We didn't used to have them fitted on our trains,then one day one failed,dug in under the sleepers and the propshaft then pierced the floor of the train and popped up in the passenger saloon between the seats!

keithjardine - 29/11/13 at 01:47 PM

Even the big players can get it wrong

http://www.warrantyguide.co.uk/vehicle-recall-4264C6458146F814802570C10045C10B-nissan-pathfinder-and-navara-recall

Darek32 - 17/12/13 at 07:15 AM

Did your prop was balanced ?

I dont think it can happend if the prop is made on new parts welded as in the books says.
My prop was balanced with that rubber silencer a the front of the shaft (gearbox side)

left side of the picture

mcerd1 - 17/12/13 at 08:35 AM

quote:
Originally posted by Darek32
I dont think it can happend if the prop is made on new parts welded as in the books says.
My prop was balanced with that rubber silencer a the front of the shaft (gearbox side)

^^ of course it can happen - even with all new parts !

all it takes is a small crack to form and grow or a bearing in one of the UJ's to fail or some minor thing like that that doesn't get spotted before it fails
all new parts welded up by a pro and balanced will be less likely to fail - but it can't ever guarantee it

or in this case it was the stupid rubber donut thing - these are probably one of the most common failures and they don't even do anything useful on our cars....

the UJ's are also quite a common failure on landrovers when people fail to regularly check and grease them and that with factory made parts with full quality control...


the moral is: Fit Prop Catchers! they won't make the prop any more or less likely to fail, but they will contain the damage
plus they are cheaper than new legs


[Edited on 18/12/2013 by mcerd1]

Darek32 - 17/12/13 at 11:02 AM

U 're right.
I will put a catcher maybe 2 just for case.

40 Inches looks good and I see it works

FASTdan - 19/12/13 at 01:08 PM

Just an update on our prop catchers - we now have new stock, revised to now be stainless steel as opposed to powder coated mild steel...







£9.99 per catcher.

scudderfish - 19/12/13 at 04:03 PM

Are they on your website? I couldn't find them

FASTdan - 23/12/13 at 07:22 AM

quote:
Originally posted by scudderfish
Are they on your website? I couldn't find them


Hi, apologies for the slow response. No not yet - only reason being I've focused purely on the inlets on the website to date. I need to add a 'locost' section. In the meantime to order just drop me a U2U.