cloudy
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| posted on 22/9/07 at 10:06 PM |
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Centering middy engine with a lobro spacer?
Can anyone comment on the sanity of moving my rear bike engine to center by adding a centric 50mm spacer to one side of the diff?
It means adding 50mm to my track - making it 1550mm disc face to face...
Would be interested to hear comments, both on the engineering feasibility and also if this is a reasonable track width still?
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RazMan
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| posted on 22/9/07 at 10:32 PM |
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Wouldn't a longer driveshaft be a better option, or have I missed something? Can't see why a spacer wouldn't work though.
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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cloudy
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| posted on 22/9/07 at 10:34 PM |
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purely through ease of build, I'm not sure i like the idea of cut and shut driveshafts...
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joolsmi16
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| posted on 22/9/07 at 10:45 PM |
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drive shafts
Try: http://www.berrisford.co.uk/page_info.php?pages_id=6&pages_name=Driveshaft%20Information&osCsid=ao6eaq5s6vq5rdahmblomdpgc7
They made a pair of driveshafts from a mock-up I made from the car shafts prices start from £80 each and unbreakable from £160.
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RazMan
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| posted on 22/9/07 at 10:58 PM |
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Personally I wouldn't cut n shut a driveshaft, although many do.
GB Engineering made mine up from a sketch and were very quick and reasonable.
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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cloudy
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| posted on 22/9/07 at 11:00 PM |
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OK, assuming I do that, what's the ideal track for a seven sized car? 
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D Beddows
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| posted on 22/9/07 at 11:12 PM |
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That's like asking what the ideal compression ratio is for an engine 
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mark chandler
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| posted on 22/9/07 at 11:13 PM |
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Track is a ratio based upon wheel base, 1.63 from memory, summit like that.
So how long is your wheelbase going to be ?
Regards Mark
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D Beddows
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| posted on 23/9/07 at 12:01 AM |
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That's just the best aesthetic ratio though isn't it? ie why a Caterham looks somehow 'right' compared to most other 7alikes.
Having said that I'm quite fond of the 'if it looks right it is right' school of engineering
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sgraber
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| posted on 23/9/07 at 03:43 AM |
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I doubt your Bike engine will have enough torque to break it as long as you don't repeatedly clutch dump it...
What type of alloy to use? T6061?
Will it be less expensive to machine that part rather than just have a 1/2 shaft made to order?
G.
Steve Graber
http://www.grabercars.com/
"Quickness through lightness"
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bimbleuk
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| posted on 23/9/07 at 05:49 AM |
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We're using the "unbreakable" driveshafts on a Radical Clubsport with a 200BHP Hayabusa, LSD, slicks and full aero downforce. So
they've had plenty of abuse inculding many standing starts and no issues yet. Though we've broken one gearbox and one clutch so far.
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cloudy
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| posted on 23/9/07 at 08:19 AM |
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Yes, cost wise I'm looking at about £20 instead of £80
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Mal
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| posted on 23/9/07 at 09:34 AM |
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Spacer
The spacer will put more overhung load on the stub shaft and support bearings in the diff.
You wil probably get away with it, but you should ensure that the locating diameters at each end of the spacer have good concentricity to minimise out
of balance forces caused by any run-out.
Mal
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froggy
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| posted on 23/9/07 at 11:32 AM |
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my kitten has cut n shut shafts on it and no problems so far, i doubt a bike engine can trouble a properly sleeved drive shaft as they are all pretty
low weight and will spin the wheel well before any seroius load goes through the shaft
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oadamo
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| posted on 23/9/07 at 11:57 AM |
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the company we use at work said that they can respline shafts. so iam taking mine to get them done ill let you no how much they cost me when there
done. ive had the same prob getting shafts done at a cheap price i was quoted over 200 per side. but this place iam looking at 30--50 per side and
they will be a lot stronger being resplined.
adam
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MakeEverything
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| posted on 22/7/08 at 08:57 PM |
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quote:
Originally posted by oadamo
the company we use at work said that they can respline shafts. so iam taking mine to get them done ill let you no how much they cost me when there
done. ive had the same prob getting shafts done at a cheap price i was quoted over 200 per side. but this place iam looking at 30--50 per side and
they will be a lot stronger being resplined.
adam
How did you get on Adam? I might be lookng for some half shafts.... which would solve the problems ive come up against with chains jumping off, and
IRS...
[Edited on 22/7/08 by MakeEverything]
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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MikeR
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| posted on 22/7/08 at 09:55 PM |
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berrisford no longer do the 'cheap' 80 quid shafts, they're 160 or nothing.
I've found a bloke (via Bob on here) that will do them for about 60 quid a side. Dave Mac (dave mac propshafts) will make new shafts or friction
weld old shafts. The friction welds are good for 200bhp in a production car (he pointed out its how Audi make the drive shafts).
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Fred W B
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| posted on 23/7/08 at 11:28 AM |
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I see no problem with the suggestion of the spacer
Cheers
Fred W B
You can do it quickly. You can do it cheap. You can do it right. – Pick any two.
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britishtrident
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| posted on 23/7/08 at 04:56 PM |
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Only valid reason for centering the engine is to move the CG --- and moving the engine two inches isn't going to move the cg much. Unequal
length drive shafts don't matter on the rear -- no torque steer effects.
If you do use a spacer take great car with the bolts --- the tightening tension (ie torque) will be critical.
[Edited on 23/7/08 by britishtrident]
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NS Dev
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| posted on 24/7/08 at 09:00 AM |
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quote:
Originally posted by MikeR
berrisford no longer do the 'cheap' 80 quid shafts, they're 160 or nothing.
I've found a bloke (via Bob on here) that will do them for about 60 quid a side. Dave Mac (dave mac propshafts) will make new shafts or friction
weld old shafts. The friction welds are good for 200bhp in a production car (he pointed out its how Audi make the drive shafts).
eh, since when???
They were doing them in January
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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NS Dev
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| posted on 24/7/08 at 09:02 AM |
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quote:
Originally posted by bimbleuk
We're using the "unbreakable" driveshafts on a Radical Clubsport with a 200BHP Hayabusa, LSD, slicks and full aero downforce. So
they've had plenty of abuse inculding many standing starts and no issues yet. Though we've broken one gearbox and one clutch so far.
We ran a Radical same as above (SR3 I assume) and smashed the standard Quaife driveshafts at the second meeting.
Swapped to berrisford gundrilled and they did two seasons with no signs of problems at all.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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