1275 is in..

[Jackmansell]

... and so far.... its lovely! took me a while to get it running as the dissy had broken parts, but its smooth and pulls well. now im wondering, what would be best for my car. should i fit disc brakes? if so, which kit? would a type 9 5 speed be recommended? they seem very expensive to me. i have heard that changing my diff to a 3.9 would help, anyone done this? the engine is currently on a HS4 with an LCB stainless 1 1/2" exhaust and its really very quiet, my dad is trying his best to get me to pick up a set of twin webbers and really make it go, dont think my half shafts would deal with that though.

[Jackmansell]

here it is, ignore the dirt haha https://scontent-lhr.xx.fbcdn.net/hphot ... e=55D78C93

[bmcecosse]

FORGET Webers - twin or single - they will drink fuel and not make any difference to the performance.. The limit is the cylinder head and the camshaft at the moment. If you improve them -you would move up to a larger single SU carb - HS6 or HIF 44............ Brakes - how deep are your pockets..? And yes - a 3.7 final drive would be ideal, but pricey these days - a 3.9 is almost as good, and not as expensive... Either is going to be MUCH less expensive (and a whole lot less hassle) to a type 9 conversion......

[philthehill]

If you want to run a pair of Weber cars you will need either a Richard Longman conversion which only uses a single choke of each carb or a 7 / 8 port head. Both not cheap and as bmc says they do drink petrol.
But to give you an taster here is the twin 45 DCOE Weber set up on my 7 ported Minor head.[frame][/frame]

And yes your transmission will need upgrading to deal with the power.
I agree with bmc's suggestions given above and unless you are going to do a lot of high speed long distance motoring the 1275cc midget gearbox and with the lower ratio final drive fitted - is the way to go.
As regards brakes there are several options available which are good - so you makes your choice & pays your money.

[Jackmansell]

its his mini racing days of the past coming through, i didnt think it would be a good idea ha. at the moment im in the process of having my floor restored, so once thats done i may save up and opt for a 3.9/3.7 diff and a midget gearbox, im not intending to race it nor do i do many motorway miles, i just want him to cope with the brilliant drivers of birmingham esm and bull motif both do disk kits but BM's one is more expensive as it advertises it's 'recommended' is there a difference between their kits or will esm's one do just fine?

[Jackmansell]

also what head/camshaft changes should i make?

[mike.perry]

I would not worry about a Midget box unless one landed on your doorstep, first gear still wears out and sounds like a bag of spanners and spares are getting in short supply. With the close ratios you will find yourself reving the engine more especially if you are carrying a load, eg uphill in a Traveller towing a trailer. This would be more noticeable if you have a 3.9 or 3.7 diff. The Midget was a lighter car and was slightly lower geared with 13in wheels.
Brakes. If you can find a set then Wolseley 9in front drums are the ones to go for

[bmcecosse]

Indeed - the 9" W drums are excellent /inexpensive and easy to fit! Head change - well again - how deep are your pockets - but a 'large inlet valve' version of the 940 head is a starting point - and then you can modify it along well trodden paths... Unless willing to lighten and balance the engine - you need to keep to 6000 revs - so nothing too adventurous in the way of a camshaft..... the MG Metro cam was 'designed' for use with the 1275 engine without excessive revs - and a certain Mr A C Dodd makes great claims (probably well founded) for a camshaft he has developed to maximise torque and power on a 1275. Again - not cheap!!

[grumpydad]

Hi
Ac Dodd camshafts are great
and much cheeper than swiftune
you will find him hear

http://www.theminiforum.co.uk/

[philthehill]

The MG Midget/Sprite 1275cc gearbox is a stronger box than either the 948/1098cc gearboxes and should be the gearbox to aim for if the engine is to be tuned and the price of a type 9 conversion is considered to be extortionate.

As regards the disc brakes - the good old Marina conversion (Pt No: MOD201C) from Bull Motif is I consider a good value for money (£329 plus the usual) conversion and parts are cheap and still readily available.

[bmcecosse]

Some pictures 'borrowed' from Mr Dodd show you what to aim for - and his range of camshafts. He is highly respected in the Mini world for his work - unlike some others.... I had better not name... [frame][/frame][frame][/frame][frame][/frame]

[M25VAN]

Drooooooool. What with that picture and the one of a nice shiney Oxford welder the other day, I need to have a sit down....

[bmcecosse]

The RS cam is probably the sensible choice for a 1098, but quite high lift - so take care if using a 940 head. And RS + for a 1275. neither running to super high revs, so not needing lightening /balancing.

[Jackmansell]

thanks guys, and yes his work looks superb

[billymonkey111]

I'll be keeping an eye on this, my medium/long term plan is 1275.

All the reading around I've done so far suggests that twin carbs aren't worth it, tuning hassle for no real gain.

And that really for modern motorway driving a 5 speed type 9 box is a very sensible option, albeit expensive.

Keep us posted!

[philthehill]

As regards twin carb hassle - it depends on what twin carbs you fit
I have never had any hassle with either the twin HS2 or HS4/HD4 carbs fitted to my Minor and other twin carb set ups (Stromberg/Solex etc) that I have been called upon to re-build, re-set and re-tune.
Even the single humble H2/HS2 can be made to give improved engine performance.
Twin carbs of any make should not be written off as they can be made to work.
But like every aspect of tuning an engine it is no good doing anything in isolation - improvements have to be co-ordinated to get the best out of an engine.
Below is a picture of a pair of SU HD4 carbs previously fitted to my Minor and they gave quite an improvement in performance. [frame][/frame]

As regards the type 9 and long distance motoring -
In 1996 I was driving from Hampshire to Cumbria & return every week - a distance of 375 miles (each way) in my series 2.
The only transmission improvements were the installation of a Marina rear axle (4.22 ratio) and Marina wheels fitted with 155 x 13" tyres and the gear box was standard 1098cc. It was a pleasure to drive on the M5/M6 and kept up and mostly overtook the average speed vehicle with a friendly wave.
So my point is that there are ways of getting round the hassle and expense but it does take a bit of forethought.
Phil

[bmcecosse]

'Twin carbs' as such offer very little improvement over a single carb of the same size. Remember that each piston sucks in air individually - so a single carb is more than enough. The main advantage is that the intake manifold is NOT heated in any way - and the run into the head is straight, not twisting, although it is spoiled somewhat by the cross tube to the other carb. There is NO significant cross flow through that pipe - it's there to ease perceived difficulties of setting up the carbs... And of course - 'twin carbs' are good for Pub Points! A larger bore single carb on a GOOD aluminium alloy inlet manifold with no water heating is a better bet for performance. I have used twin H4 carbs in the past - on single long stub inlet pipes - and they worked well - but had I known what I know now - a single HS6 would probably have been even better. There is no mystery or difficulty in setting up twin SUs - all you need is a length of 1/2" bore tube, an ear, a screwdriver and the lift pins on the side of the carbs. And once set - I've never found any reason to think they would go 'out of tune' - why would they ?
Phil's twin weber set is slightly different - for absolute top power the straight run into the head ports is important, and the 7 port head and webers allow that. I do have to say though that years ago when I helped my mate with his racing Mini - he tried 8 port head (and he had no lack of cash - so had all the 'latest' ideas on his engine) , then an 'angled valve' 5 port head from Longman with split webers, and settled finally on twin HS6 SUs (modified internally) on single stubs leading straight into the Longman head ports. He won the Scottish Saloon Car Championship that year!

[IslipMinor]

Roy,

Do you have a clearer version of the Dodd camshaft specs? Looking at the posting it looks like the cam timings are fairly typical, but the valve lifts are quite a bit more than the likes of Kent, Piper, Swiftune etc.? I have tried searching for an AC Dodd website, but only come up with Minifinity - does he have a website of his own?

[bmcecosse]

Richard -I borrowed the pictures from his facebook page. The cam page is headed ML Motorsport for whom he seems to do contract work. They used to have a webpage although just at the moment I don't see it. He develops his own spec for the cams - trading torque for power where necessary - they seem to be v highly thought of! There was a 998 Mini on yesterday developing 60 bhp at the wheels on the RS cam - using a head modified to slightly better than 295 head spec - and a single carb of course. It had great torque from 2000 rpm right up to almost 6000 where the power started to fall away.