Photo Archive
Building: The longest winter rebuild ever!
posted on 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.
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.
Photo Archive
Building: Xflow MK "book" chassis + mods. Built
posted on 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]
Work-in-Progress: Changed to Zetec + T9. Still trying!!
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.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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.
--
Never argue with an idiot. They drag you down to their level, then beat you with experience. Anonymous
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.
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............
been a bit of a rush job really, bodged it all together in just 5 1/2 years.
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.
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.
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 ?
