Lotus Twin-Cam Mini

Lotus Twin-Cam Mini

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Mike_Cerb99

Original Poster:

97 posts

189 months

Sunday 18th October 2009
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Hi everyone,

This may be a long shot but worth an ask.....I recently read a report on Himley Hall Mini Show 2009, where there was a lotus twin cam powered mini. The engine was mounted transverse, front engined, front wheel drive (see below). I am considering a similar project but have only come across gearboxes etc set up for an inline engine mounting / rwd......does anyone know what bell housing / gearbox I need to be able to mount the engine transverse, over the driving wheels?

Alternatively, if that mini was yours, please get in touch - it'd be great to talk about / compare projects.

Thanks,
Mike


PJR

2,616 posts

219 months

Sunday 18th October 2009
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A handful of people have done this conversion. If I remember rightly........ That engine is based on the Ford BDA engine (which Lotus reworked). Some cunning chap devised a way of mating the BDA engine onto the A series box (many many years ago. Possibly for racing purposes). So if the BDA could be made to fit to fit, then so did the Lotus twink.
I don't know that actual car you posted there, but yes, im betting its largely a very familiar A series type gearbox under that lot.

As for who exactly devised a way to get the 2 to mate together and what parts are involved, I forget! Im sure someone here could fill you in though smile

P,

Edited by PJR on Sunday 18th October 17:02

guru_1071

2,768 posts

241 months

Sunday 18th October 2009
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you need the following bits.....

1) mini gearbox with its mounting flange altered to suit the ford block - not that hard to find, they turn up on ebay a fair bit.

either:

2) a nose piece to bolt to the ford crank, again not to hard to find or make, the trouble is making sure that its 100% in line with the crank. they have a terrible reputation for falling off.

3) a one piece 'mini-ford' crank, they do exist, but are very rare, most are (IIRC) based on very short stroke stuff (for class limit sizes in racing)

4) either a ford engine (kent i think) or a lotus motor!

either way its an expensive project that still has the 'weak link' of the a series box, unless of course you make it bomb proof and undrivable on the road. id say the ones you see at shows will be fairly de-tuned to make them useable - and good effort to the owners for sticking with them, as they are a thing of beauty!

Shoot Blair

3,097 posts

183 months

Monday 19th October 2009
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I looked into this very seriously. It's got to be worth a shot. Some people have silly ideas to what the kits are worth.

The ebay user barbara0540 had a kit for sale that I was umming and erring about buying and it finished with no bids....ages ago. It was £600 and was a 1600 crossflow on a complete gearbox.

Give her a shout and tell us how you got on.

I've got a full race 1430 instead smile

Mike_Cerb99

Original Poster:

97 posts

189 months

Monday 19th October 2009
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Thanks for all of your replies / hints / tips / ebay contact etc....the project is still in it's early days so fingers crossed the bits come up at the right price - if anyone knows anyone that has any of the adaptor plates, please give us a shout. Thanks again, Mike

interloper

2,747 posts

262 months

Monday 19th October 2009
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PJR said:
A handful of people have done this conversion. If I remember rightly........ That engine is based on the Ford BDA engine (which Lotus reworked).
I hate to be a pedant but the Lotus Twink came first. The twin cam was based I believe on an old Ford side valve engine (with the Lotus designed head replacing the rubbish side valve one). The Cosworth BDA came along later. The Lotus engine had already appeared in mk1 and 2 Cortinas and it had a very short life in the MK1 Escort Twin Cam, the replacement was of course the the BDA propelled RS1600.

530dTPhil

1,383 posts

225 months

Monday 19th October 2009
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A word of caution against cutting corners on this type of engineering project.

I used to race in the Special Saloons at Castle Combe. Around 1990/91 a good friend (Alan Woodridge) joined the series with a BDA engined Mini; he bought the car after it had been professionally converted. Unbeknown to him, the engine builder had used a flywheel assembly machined from a standard cast Mini unit rather than a new one that had been machined from solid.
During one of the races, the flywheel exploded as he changed down for Quarry Corner; shrapnel went everywhere, including into Alan's legs. He died about three weeks later from an embolism resulting from his injuries.
A sobering thought.

Edited by 530dTPhil on Tuesday 20th October 05:41

PJR

2,616 posts

219 months

Tuesday 20th October 2009
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interloper said:
PJR said:
A handful of people have done this conversion. If I remember rightly........ That engine is based on the Ford BDA engine (which Lotus reworked).
I hate to be a pedant but the Lotus Twink came first. The twin cam was based I believe on an old Ford side valve engine (with the Lotus designed head replacing the rubbish side valve one). The Cosworth BDA came along later. The Lotus engine had already appeared in mk1 and 2 Cortinas and it had a very short life in the MK1 Escort Twin Cam, the replacement was of course the the BDA propelled RS1600.
Thanks. Fords were never my bag. Hence my blatant lack of knowledge on them tongue out




Im pretty certain Keith Calver built a similar Mini many moons ago. Might be worth contacting him. His website is here with contact details: www.calverst.com

P,

Mike_Cerb99

Original Poster:

97 posts

189 months

Tuesday 20th October 2009
quotequote all
530dTPhil said:
A word of caution against cutting corners on this type of engineering project.

I used to race in the Special Saloons at Castle Combe. Around 1990/91 a good friend (Alan Woodridge) joined the series with a BDA engined Mini; he bought the car after it had been professionally converted. Unbeknown to him, the engine builder had used a flywheel assembly machined from a standard cast Mini unit rather than a new one that had been machined from solid.
During one of the races, the flywheel exploded as he changed down for Quarry Corner; shrapnel went everywhere, including into Alan's legs. He died about three weeks later from an embolism resulting from his injuries.
A sobering thought.

Edited by 530dTPhil on Tuesday 20th October 05:41
a sobering thought indeed....thanks for the warning....The ford-mini conversion seems a feasible route providing it's doe properly.....I'm still sligtly surprised that no other gearbox (other than a Hewland) will fit with the Lotus Twin-Cam...any other non-mini gearbox suggestions???

OldtimerJohn

2 posts

181 months

Friday 23rd October 2009
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Well... this is another reminder of why I kick myself from time to time!!

My dad had one of these in the late 1970's. It was built for the then popular, Autocross racing commissioned specially for him by somebody in his back shed (don't know who now!). It was super quick and often won ftd awards only being beaten by a v8 4 wheel drive special. I still have the converted cinefilm on DVD of this thing in action all across Kent. It was certainly a one off special in its time and I remember hoards of people always peering at the front end in the paddock.

It was indeed built on a pushrod Ford block with the Twink head and mated on the mini gearbox. I was only 14-15 at the time but I remember working on it during the winter seasons in my dad's workshop garage and I was the only one whose fingers could turn certain nuts in tight spaces! There was the bolt on flywheel nose and as mentioned above, this was critical to get right. It did fall off once when an engine builder didn't torque the bolts up quite enough!! There was a spacer on the block to bring it out to meet the flywheel housing. This was machined from an alloy engine part off an Alfa. How do I know it was Alfa?... It still had part of 'Alfa' embossed on it!!

Bored with winning so much, my dad turned it into a special saloon car racing at Brands Hatch and Lydden circuits. This was its demise as it soon proved unreliable and also fell into the wrong class (being 1600). Before giving up racing, he shoved a 'normal' A series in the car with mixed results.

Anyway, when I went to Uni I wasn't into Minis and so I sold the whole Lotus kit for my dad to a mate on my course. I think he paid £150 and went off with a big grin! To this day, its the biggest regret I have and in recent times I have always wanted to replicate it. Hindsight hey? I did approach a well known mini boff in Ashford who does have a crank for a BDA version but he wasn't willing to let it go without being involved. Never mind.

Good luck with it!


guru_1071

2,768 posts

241 months

Sunday 25th October 2009
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OldtimerJohn said:
£150
arrgggggg!!!!!!!!!!!!!!!!!!!!!!!!!!!!



FWDRacer

3,564 posts

231 months

Wednesday 28th October 2009
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A better Twincam set-up is the BMW K1100LT/K1200RS Bike Head on the Mini bottom end. Parts and kits are available off the shelf and you don't need to mess around with the bottom end.

Shoot Blair

3,097 posts

183 months

Wednesday 28th October 2009
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That's true, but a Ford Block on a mini box is period and rare.

Anyone who wants performance would fit a BMW 16v head. People that want a talking point are likely to fit something odd.

Besides, a Lotus Twink or a good Crossflow, say 1760 with a decent set of carbs would blow the st out of a BMW 16v. I know they produce lots of welly, but they aren't suited to ultra high revs and to get the best out of them, you will need big bores and strokes.

What would be really interesting is whether you could fit a 4AGE engine on one, as the bolts are pretty much the same as the old 711 block. That would be like a cheap reliable BDA.

Having said, the gearbox would probably explode. But then again, you could go with dog engagement to speed things up more.

I just decided to tune the nuts off a 1430. You get a greater sensation of speed in a peaky engine. It's more frenzied.

The snag with the Ford kit will be getting a final drive which will allow it to have legs, but with a useable first.

duncancallum

845 posts

185 months

Wednesday 28th October 2009
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have a look on TMF one of the lads in trinidad has put a 4age on a mini box

Shoot Blair

3,097 posts

183 months

Thursday 29th October 2009
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duncancallum said:
have a look on TMF one of the lads in trinidad has put a 4age on a mini box
Wicked. That sounds brilliant. smile

FWDRacer

3,564 posts

231 months

Thursday 29th October 2009
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Linky??? For us lazy feckers hehe

BoRED S2upid

20,318 posts

247 months

Thursday 29th October 2009
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What kind of BHP does this conversion give you?.

Shoot Blair

3,097 posts

183 months

PJR

2,616 posts

219 months

Friday 30th October 2009
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Shoot Blair said:
Need to be registered there just to see the picts unfortunately banghead

kremlingazette

125 posts

187 months

Wednesday 11th November 2009
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I knew someone with a Lotus TC Mini, it had a straight cut Colotti gearbox.