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head choice??????????
paul_mcq - 14/2/05 at 02:52 PM

well lads hows it going, i'm tuning my a series up and need to now if there is much difference between a stage 3 and a 4. theres bout £100 difference is there any performance change?

stevebubs - 14/2/05 at 03:18 PM

To be honest, it depends on who is doing the tuning.

Marcus - 14/2/05 at 08:21 PM

I agree with Steve, one man's stage 3 is another man's 4!
I was once offered a stage 3 crossflow with STANDARD sized valves.
You're probably not going to get the benefit from stage 4 (also known as full race) on the road. If it's going to be a track car it may be worth it, depends on the spec of the rest of the engine.

Marcus

Jon Ison - 14/2/05 at 09:14 PM

if they a proffesional heads ask how much they flow......if they dont know they aint been developed properly.

compare the flow rates, not as stated above "stage 3" "stage 4" that could meen anything.

allso beware polished ports....

[Edited on 14/2/05 by Jon Ison]

paul_mcq - 18/2/05 at 01:32 PM

cheers lads. i'm looking to change the pistons in the engine which i need bit of adive which ones to go for. i'm putting bigger ratio rocker arms in and a race cam. keeping the 1.5 in su carb. is there anything else i can do to inhance the engine?

britishtrident - 18/2/05 at 01:45 PM

Put a 998 Imp engine in :-) been done a couple of times using the Mini gearbox and lots of alloy welding but the results are IMPressive.

Stu16v - 18/2/05 at 05:42 PM

quote:
Originally posted by paul_mcq
cheers lads. i'm looking to change the pistons in the engine which i need bit of adive which ones to go for. i'm putting bigger ratio rocker arms in and a race cam. keeping the 1.5 in su carb. is there anything else i can do to inhance the engine?


With an A series engine, the only thing that restricts engine tuning is the amount of money you want to spend.

I have played with quite a few A series motors over the years. The head is a good place to start, and the biggest restriction in getting power out of the motor. I wouldnt advise fitting a race cam, especially if you intend to run a single carb. All it does is push the usable power right up the rev range - to the point where you need better/bigger carbuation, so you end up with an engine that is a pig to drive, and restricted power at the top. Net result, a worse engine than before! The high ratio rockers will accentuate this. Instead, go for a fast road/rally cam (with your rockers...), a lot better suited IMHO.
If you can find one, fit a carb and manifold off an MG Metro. Not the ideal solution, but far better than an 1 1/2 SU. A nice LCB exhaust manifold and a decent exhaust, to finish off, and you will have a lovely little engine.

A word of warning, make sure that the valve springs are capable of coping with the extra lift of your chosen cam, with high lift rockers. Quite a few standard ones wont...

Finally, they are quite expensive, but IMO make *such* a difference to the sound/smooth running of the engine - a cam belt conversion kit. Quite simply the best thing I did with my Mini...


HTH Stu.

NS Dev - 18/2/05 at 05:45 PM

Just to back up Stu's point, bin the 1.5" su and fit 1 3/4" su and water heated manifold from an MG metro, definitely the simplest and most effective mini trick in the book!

Peteff - 18/2/05 at 08:09 PM

A good exhaust, something like the Maniflow system with a Cooper 3 branch or LCB really makes a difference to a standard engine. My old one pulled like a train with just a head clean and skim, exhaust and carb/manifold sortout. It was only a 998cc but it used to go well.

Marcus - 19/2/05 at 10:25 AM

My mate just had his 1275 Midget on the rollers, was expecting 50 - 60 at the wheels, has 45 weber, oselli head, 285(ish)cam and an LCB manifold. Was gobsmacked when readings came back at 85 bhp at wheels!! That's a serious A series. (tested at John Noble in Chesterfield so I believe it)

Marcus