Lotus/Crossflow onto Mini gearbox

[kneegrow]

Ok, I have decided instead of putting an expensive unreliable race engine in my mini, I am going to pursue the Lotus TC engine mounted on a mini gearbox. This is reliable however I am having thoughts about other options. Can anyone tell me which other engines share the Crossflow/TC sump bolt pattern. These modified gearboxes are available but I hear that the CF and the LTC are not that great when compared to other engines. What typical output should I expect from a Lotus TC or a Modded Crossflow? The other option is to put a blower on a big Mini engine but this can get pricey and unreliable. Has anyone blown a crossflow? What happened......
All input recieved with thanks....stu

[jv_as]

Why do you want to keep the mini box? if you are prepared to do the work wouldnt you be better off using a tuned vauxhall twin cam. Lots of mini specialist and tuners prefer this as a more realistic way to go and I presume that they just implant a front wheel drive box from a vauxhall aswell.

[Paul V]

Lotus twin cams, Crossflows and even BDA Cosworth engines were used for these conversions, this seems to have been taken over by Vauxhall and VTEC conversions, with the newer conversions you have reliable power, the engines are easily available and come with a 5 speed box built to take it.

[kneegrow]

I am aiming to whack it in an early MK1, I want the track the same. Honda Conversions look silly with the wheels outside of the wings. You need big arches and it looks basically naff. A well built SC box will handle the power without problems. A BDA is probably going to be difficult to find (although I know where there is a rusting MK1 Scort rally car in a farmyard). The tuning books I have read on the crossflow have not been very informative. I am toying with keeping the RPM in its usual limit and using a blower, with a taller FD. Lets face it, if you want to go modern, use a bike engine.

[interloper]

Most modern engines come with a gearbox desinged for front drive aplications where as the TC or BDA dont.

You will need a classic mini sump/gearbox that will fit under the TC engine, if you can find an original converted box problem solved but if not it sounds like a major engineering undertaking to get one to fit.

I believe most of the Honda conversions you find have wide arches and big wheels for several reasons. The main reason seems to be to get the biggest tyres on for to provide high levels of road holding. Larger wheels also mean bigger brakes, very nescary when running 200 + bhp.

The other reason is that the wheel arches camoflage the fact that the nose is normaly lengthened to acomodate the modern engine.

I dont believe the track is in actual fact any wider than standard.

[kneegrow]

I will use a mutant mini gearbox, probably with dog gears (they are wider), the TC fits under the bonnet whereas the crossflow does not. The BDA is an unknown quantity to me and might be worth pursuing as it is alloy. I have to relook at the different stroke lengths and see about building a low compression engine with a blower which will be easier to accomodate than twin 45's. Possibly out of an MR2. The wheels are 7" mags (10") and will be wearing large rubber. I want to create something which looks like a standard grannies shopping trolley with big wheels. A real stealth. These wideboy conversions are just blantantly tasteless and rude.

[interloper]

Actualy thats pretty cool it will have a more authentic period feel to it, whereas dropping a K series, Honda Type R or Vaux unit wont ever.

Good luck with it and remember to post up some piccies of it when its done.

[kneegrow]

I have been looking at specs of these engines and I am not that impressed. I am thinking along the lines of 1600 Kent block with lotus BV/TC head, a 4agze supercharger blowing about 10PSI and sucking through a 2" SU. With the throttle body as close to the ports as I can get it. Over 160hp would be nice. I reckon that should give the gearbox a break.

[interloper]

I'm aware of turbo'd minis running 150 + bhp a decent straight cut box should be able to handle the torque. But for actual experience and proper advice you had better talk to the chaps on the mini forum about your plans.

[zzr1200]

kneegrow said:

I am aiming to whack it in an early MK1, I want the track the same. Honda Conversions look silly with the wheels outside of the wings. You need big arches and it looks basically naff. A well built SC box will handle the power without problems. A BDA is probably going to be difficult to find (although I know where there is a rusting MK1 Scort rally car in a farmyard). The tuning books I have read on the crossflow have not been very informative. I am toying with keeping the RPM in its usual limit and using a blower, with a taller FD. Lets face it, if you want to go modern, use a bike engine.

When the Mk 1 Fiesta XR2 came out a turbo version called Lumo 105T was sold that raised out put on the standard crossflow from 84BHP/91lb ft to 118BHP/128lb ft without any mods to the basic engine apart from the turbo install. It used a Pace turbo giving a max boost pressure of 7psi.

Hope this helps in your decision.

Paul

>> Edited by zzr1200 on Sunday 21st September 22:29

[phil hill]

This has been done before, both Lotus and Crossflow. There used to be an adapter plate and crank tail with approprete oil pump drive gear kit available. I'll have a look and see if I can find the details, but if you find a copy of Vizzard's "How to modify your mini" there are pictures in there. I know the book was originally published in the '70s but most of the vendors live on in one form or another.

[kneegrow]

I have read Vizard and chatted to a bloke in the pub (ex ford works rally driver) and he said it was the way forward. I can't get any more info than pictures and the odd story. I hear the 711 block and the Lotus BV head make a good combination. The Mini guys are all playing with A series or Jap stuff. I have yet to find a good book on Crossflow tuning. As the CF has a big bottom end and mains, blowing seems a good idea as I would be able to boost power without having to go the whole steel bottom end. The gearbox guts are going to be pricey. There are lots of these conversions hiding around but no-one seems to have much to say about them. It strikes me as the ultimate setup as a similar HP A series will be peaky, cammy and fragile. Sounds great..........stu

[heightswitch]

How many cars have you built? and how many transplants have you carried out?

Why go to all this hassle for a road car.

Why not just put a properly build turbo charged A+ engine in your mini. This can be fitted by a DIY mechanic with average capabilities for reasonable money and will sound like a mini should.

A BDA engine or lotus twink, is unreliable when tuned and will cost more to build (£7-9k) than a Mark 1 mini is worth.

You will need engineering skills, a lathe, machining skills, trick mounts trans adaptors etc. etc. before you can even think about lowering in the engine and box.

[gary_tholl]

I'm a Lotus nut, so I've done some homework on the twin-cam (I have a '74 Europa with the big valve twin cam). You're going to be hard pressed to get 150+ hp out of it. I haven't heard of anyone charging one and having it live a usefull life.

The Cosworth BDA is the same block, just a different head (16 valve vs. 8 valve) can free up quite a bit more power (I have a BDD that has 220+ hp) but it is very peaky and not much torque and bloody expensive if it does go bang. Again, haven't heard of people charging one of them either.

If you want lots of power reasonably reliably that is period correct, go with a BDA tuned to ~180 hp. It will be pricey though.

If you want that much power cheap and reliable, go with a newer engine.

The LTC isn't much cheaper than the BDA, but can't make as much power.

I don't really know where to get a good book, Vizard has some good ones for twincams and cosworths.

Hope this helps,
Gary

[Mr2Mike]

Rover V8 on top of an Austin Princess gearbox. Combine the best attribute of a Tiv in a mini shaped package!

www.geocities.com/jharkola/Viku2.html

[kneegrow]

OK, I have 2 minis, a 66 and a 67. The original idea was to do a crazy supercharged 1275 using a MR2 blower. That is going to happen to the red one. The blue one is going to cop a 711/TC Lotus/Ford with an MR2 or more probably Rootes blower working with an upside down modified crossflow, single weber manifold with the blower blowing up into this and sucking through a BIG SU carb. This will reliably give me more area under the horsepower curve with little distortion of the curve. This gets rid of the "Weber bulge" and lets me use the area by the clutch for the carb. Anyway, I have been mucking about with cars for about since I was 17 and am getting there knowledge wise. I will build the blown engine first whilst getting parts for the Lotus/Ford and then use my experience to build it properly. I am looking for something to pull a FD of about 3:1 reliably through a bombproof gearbox. It should perform similar to my A series with a 3.44. Should be looking at 100hp at the wheels in each case. the reason I need 2 is so that I can rebuild one when the other has exploded. I will keep you posted.
thanks stu

[8PortChris]

Stu from cornwall! You should spend less time telling the world what your gonna do , and get on with it.
It doesn't matter how many forums you post on , the result is still the same.... your a dreamer

Chris