scootz
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| posted on 11/6/09 at 09:30 AM |
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Blackbird Sprocket Splines
I'm converting a ZZR powered Radical to a Supercharged Blackbird engine.
I have a Quaife / Powertec drive unit from the original set up. It has LSD and reverse, so would obviously want to keep it.
 
drive
It uses a similar 'sprocket-to-prop' adaptor used on BEC's. Except it has cush rubbers and interlocks with the Powertec unit in-line
(mid-engined car).
Image deleted by owner
The original sprocket had the ZZR spline pattern cut into it... this is different to the Blackbird spline pattern.
Thankfully the ZZR spline is smaller than the Blackbirds, so there should be room for a machine shop to cut a larger spline pattern into the
original.
Still with me?
So, I guess the question is... can anyone recommend a machine shop who could cut the necessary spline pattern into my original sprocket adaptor.
Would save me a fortune as would otherwise have to commission Quaife / Powertec to make me a one off!
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twybrow
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| posted on 11/6/09 at 09:33 AM |
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The problem I found was they are hardened steel, so they are a nightmare to machine once heat treated.
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scootz
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| posted on 11/6/09 at 09:35 AM |
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I don't like your answer... give me another... 
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40inches
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| posted on 11/6/09 at 09:45 AM |
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Would a water jet cut it?
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MikeCapon
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| posted on 11/6/09 at 09:46 AM |
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Idea? Machine or internal grind out centre of cush drive. Turn down Blackbird sprocket to push fit. Weld and light skim (turned) to eliminate out of
round provoked by welding.....
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twybrow
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| posted on 11/6/09 at 09:48 AM |
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quote:
Originally posted by scootz
I don't like your answer... give me another...
Ok, try this one - stop being so tight, and buy the right one for the job! you must be loaded after selling your ZX12 lump, so you can afford a new
adaptor!
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scootz
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| posted on 11/6/09 at 11:38 AM |
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quote:
Originally posted by MikeCapon
Idea? Machine or internal grind out centre of cush drive. Turn down Blackbird sprocket to push fit. Weld and light skim (turned) to eliminate out of
round provoked by welding.....
Sounds like that may be a good plan!
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scootz
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| posted on 11/6/09 at 11:49 AM |
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quote:
Originally posted by twybrow
quote:
Originally posted by scootz
I don't like your answer... give me another...
Ok, try this one - stop being so tight, and buy the right one for the job! you must be loaded after selling your ZX12 lump, so you can afford a new
adaptor!
Nope... that one doesn't work either... 
Lost a few hundred quid on the ZX12R (oh, when will I ever learn!) and the Bird engine cost significanly more, so absolutely minimal cash to
splash!
The 'standard' Quaife / Powertec sprockets are around £200 by the time VAT, etc. are factored in. A bespoke one (don't do a Bird
one off the shelf) would be significantly more!
PS - Just in case you thought I was being ungrateful for your initial advice, I wasn't... hoped my 'tongue-out' smiley would convey
my strange sense of humour!
I genuinely hadn't thought about the hardend steel element.
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twybrow
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| posted on 11/6/09 at 07:35 PM |
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No offence taken - I knew it was tongue in cheek (or out!).
Sorry I cant be of more help.... Good luck!
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scootz
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| posted on 11/6/09 at 08:02 PM |
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Just bought a BB front sprocket for pennies on the Bay of E... will see what can be done with it!
Widz... if you're reading this, then start scratching that baldy wee brainy heid of yours!
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