arrybradbury
|
| posted on 22/1/07 at 08:21 PM |
|
|
BEC drivechain
I'm sure i've seen before, but a search hasn't thrown anything up, a BEC driven through 2 UJ's to a sierra diff. Does anyone
know who this is or where the topic is? I can't remember whether this was thought of as good or whether it had any flaws!
Thanks in advance 
|
|
|
|
|
ChrisGamlin
|
| posted on 22/1/07 at 09:10 PM |
|
|
What car are you planning installing into? If its a front engine'd RWD car such as a Locost then virtually everyone uses this method, although
you'll need a centre bearing in the middle because the distance between the engine and diff is too much to use a single piece propshaft with a
UJ either end
|
|
|
arrybradbury
|
| posted on 22/1/07 at 09:46 PM |
|
|
I'm sure the one it was mounted in was a middie with just 2 UJ's between the sprocket adaptor and the diff.....
|
|
|
RallyHarry
|
| posted on 22/1/07 at 09:55 PM |
|
|
Yeh, I remember that also.
Was a year ago (and a half?) I beleive ...
Cheers
|
|
|
mark chandler
|
| posted on 22/1/07 at 09:57 PM |
|
|
In a middy a short prop is okay so this may be correct.
The length of the prop from sprocket to diff is quite long, a single prop will be liable to aggressive vibrations and will try and destroy itself
unless balanced perfectly. You will be hard pushed to get someone to make a single piece prop from 2" tube, they would maybe if you are lucky
make one from 3" tube as this would be stronger.
Not a good idea really, its a lot of metal at 5000 rpm threatening to take you leg out if it fails.
Regards Mark
|
|
|
pathfinder
|
| posted on 22/1/07 at 10:24 PM |
|
|
dunno who's car it is tho  Image deleted by owner
|
|
|
ChrisGamlin
|
| posted on 22/1/07 at 10:29 PM |
|
|
I think someone once calculated that to make a single piece prop that was suitable for a front engine'd RWD BEC, it would need to be something
like 5" diameter. Its not the balancing as such, its the resonant frequency of a tube of that length thats the issue, so it will always be
likely to fail at a certain RPM regardless of how well its balanced.
|
|
|
indykid
|
| posted on 22/1/07 at 10:30 PM |
|
|
it was spunky.
from what i remember from seing it at newark, it was a bike engine, could well have been a blackbird, with a prop that was little more than 2
uj's, think they were bolted back to back, onto the sierra diff
afaik, he sold it some time last year, maybe the year before, but he still post pretty regularly
tom
[Edited on 22/1/07 by indykid]
|
|
|
pathfinder
|
| posted on 22/1/07 at 10:30 PM |
|
|
pic is of a Honda VTR in a midtec Spyder
|
|
|
arrybradbury
|
| posted on 22/1/07 at 10:39 PM |
|
|
I found it, but just after someone had done it on here, thanks guys, that was the pic i was looking for. So is that configuration still in one piece
and a suitable method for a BEC middie to avoid complication/cost of a chain drive?
|
|
|
russbost
|
| posted on 22/1/07 at 10:54 PM |
|
|
Spire did something very similar with a ZX12 in the Spire Gt, I think theirs was a single U/J with a sliding joint IIRC.
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
NS Dev
|
| posted on 23/1/07 at 09:14 AM |
|
|
to be honest you could do that in a variety of ways. If you want the engine that close then you could just make an adaptor to go onto the sierra
pinion flange that takes a rubber drive donut, then get a sprocket manufacturer (Talon Engineering) to make you up a flange to bolt to the engine side
of the donut, and which pushes onto the bike output spline as usual.
They quoted me £15 for that sort of item (basically a blank sprocket with 4 or 6 holes in it)
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
|
|
|
JoelP
|
| posted on 23/1/07 at 07:55 PM |
|
|
that 2 u/j method is fine IMHO, the middle piece essentially IS a prop. If you imagine the bolted flanges being a short piece of tubing etc...
And if it did fail, at least its not beside you!
|
|
|
Peteff
|
| posted on 23/1/07 at 08:33 PM |
|
|
I often thought (bit risky, causes headaches)
If you could get your engine to one side of the diff flange or above it you could use sprockets and a short loop of chain. If you got used different
size sprockets you could then vary the gearing so you don't depend on manufacturer ratios.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
|
|
|
tks
|
| posted on 25/1/07 at 08:41 AM |
|
|
no
the problem can be / is balance..
because its centered on the bolts and thats never as perfect as a straight tube wich is balanced
TKs
The above comments are always meant to be from the above persons perspective.
|
|
|
wheezy
|
| posted on 5/2/07 at 11:57 AM |
|
|
I got mine manufactured with 2 UJ's and a sliding tube in the middle. Overall length between the engine sprocket and diff flange is about 8
inches.
Dave
|
|
|
