Classic Mini John Cooper conversion

[Garipie]

Morning all
Am I right in thinking that although the John Cooper garage has closed, there are still people/garages that are authorised to retrofit the 90bhp Cooper Works kit to the MPI mini? Any links or anyone have any information on it? I did some Googling but with no luck.
Thanks,

[minimadmotorman]

If it's the performance you are after you can replicate this yourself.
Providing that your engine, gearbox & clutch are in GOOD working order and not excessivly worn.

Basics

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K&N Air Filter Element
Performance Exhaust System (CAT Back)
Stage 2 or 3 type cylinder head

More involved

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Uprated fuel pressure regulator
52mm Alloy throttle body
Superchips ICON
MPI mini friendly rolling road to setup the FPR & ICON

Optional

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You could also install 1.5 ratio rockers but I wouldnt reccomend it as the MPI cams are as soft as pensioners turds. A better solution would be an Swiftune SW5i camshaft.

MPI mini's also had very tall diff's @ 2.76:1 to pass drive by noise regulations, you would be far better having this replaced with a 3.21:1 or even a 3.44:1 if you have a 13" wheeled mini. This would transform your car's acceleration at the expense of some cruising speed.

My personal choice if i had to do it again would be a K&N air filter element, Stage 2 cylinder head, CAT back exhaust system and change the diff for a 3.21:1

This would give you a reliable 75-80bhp whilst retaining good fuel economy & performing significantly better than a John Cooper conversion (which never made the claimed 90bhp)

[guru_1071]

you need to be careful as the jc '90' bhp kit is a pain to get through the emmisions test.

ask pete cooperman about the trouble he had with one........

[FWDRacer]

Disagree on steering clear of the 1.5 ratio rockers. Even with the standard cam they will really boost mid range torque output which will be felt on the road. Added benefit of bolt on versus engine out.

90bhp might be the headline figure, but the torque output of the carefully matched collection of bits that make up these "packs" (Which anyone can do - it isn't the sole remit of John Cooper )which makes the whole engine/car more willing on the road.

[guru_1071]

i think the cam wearing problem is more to do with people setting the clerances as std ratio rockers, either through ignorance, or attempting to help with the emissions

[Naughty 40]

Palmer Brothers are now also doing a conversion,they are based in London,you should find their add in one of the magazines

[miniboy1971]

The JCG 90 BHP ‘S-works’ conversion kits are still, as far as I’m aware, available from Classic Minis in Littlehampton. This business was set up by a former employee when the JCG business wrapped up a few years ago. Go to www.classicminis-online.co.uk

I had the same kit fitted by JCG a few years before there site at East Preston closed and I’ve never had a problem, touch wood, with the emissions at MOT time.

The claimed 90 bhp would appear to be a bit of a far reaching for this, and many other bolt-on kits. Rolling road evidence taken in various mini magazines suggests that all these kits fall short of this figure.

A noted mini tuning company in the Kent actually advise to remove the 1.5 high lift rockers from these kits (as they can cause damage to the valve drive train) and the modified fuel regulator which may reduce the power output, but with the fitment of an ICON unit, you can make some adjustments to the ecu improving refinement and torque. Go to www.mlmotorsport.com

If you want big increase in power, then using the V-Max BMW Mini Supercharger conversion or Z-Cars V-Tec / Motorbike engine swap might be worth a look…..!!

[Rakey]

Or you could try Tony Franks who also used to work for John Cooper Garages

http://www.minichallenge.co.uk/index.php?option=co...

Edited by Rakey on Friday 23 January 14:05

[1293gt]

guru_1071 said:

i think the cam wearing problem is more to do with people setting the clerances as std ratio rockers, either through ignorance, or attempting to help with the emissions

Hello Guru,
what should the clearances be on the 1.5 ratio roller rockers?

[guru_1071]

1293gt said:

guru_1071 said:

i think the cam wearing problem is more to do with people setting the clerances as std ratio rockers, either through ignorance, or attempting to help with the emissions

Hello Guru,
what should the clearances be on the 1.5 ratio roller rockers?

14 - 16 thou

[Cooperman]

Last year I had a 1999 John Cooper 'S'-works car in which had done 80,000 miles from new and just would not pass the emissions part of the MoT. The bores were worn so it had to be completely stripped for full re-build. I was surprised at the poor quality of the (expensive) 'S' works cylinder head as the exhaust ports had not been touched and the inlets were not ideal for optimum gas flow either.
It was re-built as a 1330 cc unit with Hepolite 21253 pistons, a 10.6:1 comp ratio, standard rockers and a new MPI cam. All was assembled carefully, the cam accurately timed-in, the head worked on some more, new valves and guides, etc.
The owner said that it had never gone that well even when first run-in, so we were all pleased with this. It passed the MoT with ease and was well within emission limits.
The entire build, including parts, came to about £1700 including labour, but excluding taking the engine out and putting it back in again.

[tinks v8S]

i have a jcw conversion from new,on a p 1996 s5
no probs ever
palmer brothers are now doing ther own
in/out 1 day

[Garipie]

Cheers for the information everyone. On a bit of investigation I have read simular reports about the quality of the Works conversion but simularly a lot of people have raved it.

I'll keep reading up but the links you guys have given me is just what I was after. Cheers.

[Cooperman]

Garipie said:

Cheers for the information everyone. On a bit of investigation I have read simular reports about the quality of the Works conversion but simularly a lot of people have raved it.

I'll keep reading up but the links you guys have given me is just what I was after. Cheers.

If you had only drivemn a standard MPI or SPI, then the 'S-Works' conversion would seem great. However, if you had driven on original Mk 1 or Mk 2 Cooper 'S' with 75 bhp and a 3.44 diff, then the 'S-Works' would not impress at all.
It is doubtful if the 'S-Works' cars actually ever gave 90 bhp and maybe 85 bhp is a more likely figure. However, the gearing of the late cars at 2.77 or 2.9:1 final drive take the 'kick'out of the power and if the diff ratio is dropped to, say 3.2 or 3.44:1 then it would be much more useful on the road.
The lack of quality of the head work did seem disappointing, althougth the standard of polishing of the combustion chamber surfaces was really good (!) for whatever use that really is. To pay that sort of money extra for a head when the exhausts had no work done to them at all is a bit naughty. A decent head from Mini Spares, MED or one of the other specialists represents much better value.

[Mr. D]

Rocker clearances should always be 10 times the rocker ratio plus 1 thous for best wear/performance.

[guru_1071]

Mr. D said:

Rocker clearances should always be 10 times the rocker ratio plus 1 thous for best wear/performance.

really?

do you have the dyno sheets to back this up?

[Mr. D]

I have the word of a trusted engineer on the subject of the A Series who assures me this to be the case.

[guru_1071]

Mr. D said:

I have the word of a trusted engineer on the subject of the A Series who assures me this to be the case.

from my experience i would say that factors such as cam choice, engine type (be it carb or injection), application (road or race), emmisions considerations (dependant on year of engine)acceptable wear rates (in the rest of the valve train (again race/road usage)), engine size, valve length, fitted spring length (and type) even factors such as push rod length, block height and head thickness will need to be considered by the person fitting the rockers.

this is why i gave the answer i did. the ideal will be found between the two for 99% of engines

having recently seen a very, very expensive engine blow up caused purely by someone making a complete and utter hash of the calculation of his rocker geomatry i would say that no 'trusted engineer' would be glib enough to state one figure (and use it) for every type of a series application

as a starting point/rule of thumb yes, maybe

its like stating that 'every cam' should be timed in at (say) 110 degres.........

[Mr. D]

Rocker geometry and rocker clearances are not the same thing.
The engineer in question was AC Dodd who's experience I regard as good, or at least better than my own.

[guru_1071]

Mr. D said:

Rocker geometry and rocker clearances are not the same thing.
The engineer in question was AC Dodd who's experience I regard as good, or at least better than my own.

i am well aware of the differences between rocker geometry and rocker clerances, but thank you for asuming i didnt and choosing to point it out.

however, the rocker clearance does play its part in the overall geometry, and the relationship between the valve tip and the rocker arm, for example a clerance too tight will affect the wear rates of the valve tip, rocker arm, cam follower on the cam etc etc. a gap too large will do the same, but often allow the rocker (roller ones) to 'hammer' the end of the valve leading to mushrooming of the valve and occasionally (dependant on time and material) cracking of the alloy rocker - this occasionally then leads to the rocker failing and the pin dropping out, which in turn will flick the collets out of the valve cap and allow the valve to drop.