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Propshaft Slider
locoboy - 24/11/03 at 12:18 PM

Hi chaps,

Bike engine and live axle = need for sliding prop shaft.

are these available just off escort/capri/cortinas? (well anything ford live axle)

How does this work on a BEC as the slider on the cortina used to slide in and out of the end of the gearbox along the splines.

What do i do now!???


ChrisGamlin - 24/11/03 at 02:03 PM

You need a slider at the back, but you wont be using the standard Cortina/Escort prop anyway as in a BEC it needs a centre bearing and needs to be much longer. For a BEC you'll need a fabricated 2 piece prop with a centre bearing from a Transit donor, then a slider shaft in the rear (also possibly from a tranny?) with a flange in it to match the diff flange.
Speak to someone like Bailey Morris, they've done lots of BEC props with sliders etc, it wont necessarily be the cheapest option but IMO the prop is one of the few things not to cut corners on, from a safety point of view.

[Edited on 24/11/03 by ChrisGamlin]


locoboy - 24/11/03 at 02:28 PM

Cheers Chris,

I have mailed bailey Morris and asked for a price.

Is there no way you can cut up and use a tranny/sierra one?

I wouldnt do it myself but get a pro welder/ fabricator to do it.


ChrisGamlin - 24/11/03 at 03:10 PM

You can cut-n-shut one yeh, and some people have done exactly that and don't seem to have had any problems as long as its meticulously balanced. Personally, it would always be in the back of my mind, so would prefer to spend the extra and buy one that I know is up to the job, but thats not to say that the homebrews arent safe by any means.

Chris

BTW, expect a cost of about £200-£250 from BM.


locoboy - 24/11/03 at 04:21 PM

WOW £xpensiv£!

I think a well engineered cut and shut is in order.

Components
3 UJ's (1 at engine end, 1 just after the bearing and 1 at the axle end)

1 x suitable slider
1 x Main bearing.
Have i missed anything?

I am planning on only having this engine in this car for a short while then swapping it out into my new car and ideally dount want to go to the hassle or expense of making another prop to fit the new chassis,

so my next question is how much slide in a slider do you have as a rule?


ChrisGamlin - 24/11/03 at 06:04 PM

about 8-10cm at a guess, I think thats about what mine extends by.


locoboy - 25/11/03 at 09:31 AM

so with a little careful measuring and fully thought out engine placement it could in theory be possible to use the same shaft for both cars?

I plan on only making one engine cradle too, and putting appropriate brackets on each chassis to fit it ......lazy or sensible, not sure


ChrisGamlin - 25/11/03 at 11:20 AM

Yep you could use both props in both chassis. The most critical measurement is going to between the centre bearing mounting and the flange on the engine, as this doesnt have a slider section usually, so needs to be within the tolerence of the bearing mounting plate.

Chris


Peteff - 25/11/03 at 06:44 PM

I helped fit a bike engine in an Indy chassis and we fitted a slider from the front half of a plastic pig prop into the front of the car prop. This was needed as the engine was in at an angle to the centre joint. The rest was Sierra but a Transit one could be used in a live axled car I would think as the axle will only have limited travel the centre joint should cope with the up and down movement.

yours, Pete.


Jon Ison - 25/11/03 at 08:45 PM

morris marina slider at front, sierra center bearing near front, sierra prop to rear, worked 4 me........


locoboy - 25/11/03 at 09:10 PM

am i right in thinking that there is no real point to having a slider between 2 fixed points, ie the engine being solid mounted and the bearing also being solid mounted?

John, im sure you are about to tell me otherwise

Surly the up and down movement in the axle will load the bearing and mounting in a front to back direction....yes/no?

[Edited on 25/11/03 by colmaccoll]


Jon Ison - 25/11/03 at 09:20 PM

whilst the center bearing is "solid" to chassis it has loads of movement in it, may not be "the way it should be" but i did over 5k miles flat out with the slider at the front with no probs

i would guess the slider moved 5mm max but without one that 5mm wunt do engine much good ?


ChrisGamlin - 26/11/03 at 10:37 AM

Yep you can have a slider on the front as well, the only word of caution on this is that occasionally the retaining bolt on the output shaft that holds the prop flange on can fail. If you have a prop without a front slider, all you get is increased vibration as the flange is moving about on the engine a bit, but cant go anywhere. If you've got a slider on the front, the prop flange can slide off the output shaft and you have a nasty flailing prop trying to get at your feet.
It not a hugely common occurance, but I know of at least two people on the BEC list who have had this bolt fail, one ended up with major tunnel damage after the prop slid off the output shaft, the other put a new bolt in after feeling a bit of vibration.....

Chris


locoboy - 26/11/03 at 10:55 AM

So threadlock aplenty is the name of the game!

i may also get a thin piect of sheet steel welded to my adaptor so i can fold it round onto the flats of the bolt that holds it on to the output shaft, this should stop it coming undone shouldn't it? may be a bit belt and braces but i like my legs


ChrisGamlin - 26/11/03 at 11:07 AM

It wasnt coming undone, it was breaking the head off the bolt, so threadlock wont help the cause in that scenario


loafersmate - 26/11/03 at 12:02 PM

Make sure you use a decent 12.9 grade bolt!!!

Ben


locoboy - 26/11/03 at 12:38 PM

holy sheet, how the hell was it doing that, just through vibration?

a decent bolt it will be then, i guess the original sprocket bolt is a pile of poo then?


ChrisGamlin - 26/11/03 at 02:05 PM

I dont know what grade the original bolt is, I guess it may not be too hard as on the bike there should be no lateral force on it. This should also be the case with a BEC flange, but its not always the case as can be seen from the other thread about flange adapters today. If its at all loose I guess it can vibrate and move along the splines and give the bolt a good whack every time it does it.
Like I said, its not a common occurance and if the flange fits properly then you are probably 90% there with reducing the chance of failure, but if you can afford not to have a slider in the front as well (which will also weigh more) then I'd still personally go without.

Chris