Carolynn and Dave’s Mini Challenges.

The Mini Clubman Estate joined the fleet in August 2006, it needed a fair bit of work to make it roadworthy and reliable but still the engine was a tad ropey, therefore it seemed the ideal platform to form the basis of the K-series Mini conversion.

Having looked at the various subframe options I was pointed to a half finished subframe on one of the Mini forums, a few emails later and we were taking a van to stoke to pick up subframe, 1.4 16v engine and many parts, almost enough to make a complete system.

The engine we aquired was a single point engine but a multi point manifold was also supplied with the engine as was a 1.8 manifold and 1.8 ecu/loom.

Unforunately the 1.4 and 1.8 ecu’s are not interchangeable due to a different number of flywheel teeth/missing teeth. 1.4 spi/mpi ecu’s however are interchangeable. As we had an mpi loom this appears to work with the 1.4 mpi ecu we got from ebay along with another 1.4 mpi manifold.

Before fitting the engine to the frame and the frame to the car we decided it would be wise to test the engine and various components first, therefore the engine was setup with radiator and fuel pump for a trial spin before fitting, although initially hard to start it did eventually fire into life, a bit loud with no exhaust but seems to run on all 4 cylinders just fine, see following video .........

***** first start video *****

The next step is to finish the subframe, paint the engine and put the two together ready for fitment to the car...... 

The subframe didn’t need a huge amount of work to complete but in view of the importance of subframe strength i decided to re-weld some of the joints and add extra strenghtening. Also the near side lower suspension arm needed a pivot mount creating and this again needed to be very strong as it takes a lot of abuse during ‘spirited’ driving. Having completed the subframe strenghtening the next job was to remove the tired 1100cc engine. Followed by a trial fitting of the k-series to the subframe such that it could be used to work out which parts of the inner wings etc needed to be removed with the aid of an angle grinder. The subframe/engine assembly was put on some moveable platforms and wheeled underneath the car to see where to cut, without the inlet manifold, exhaust and so on there appeared to be lots of space but this would prove not to be the case when the inner wings were cut away.

With enough of the inner wings cut away to allow the subframe to mount on the towers a trial fitting of the inlet manifold showed that it would not clear the brake and clutch master cylinders, in fact even if the clutch master cylinder was removed it still fouled the brake master cylinder, therefore two modifications were required, one to remove the clutch master cylinder and replace it with a clutch cable which would work better with the k-series clutch anyway and secondly to replace the brake master cylinder with a smaller version with remote fluid resevoir. Along with the two changes much of the bulkhead/cross member needed removing to allow clearance on the inlet manifold also.

To convert to a cable clutch required the pedal box being modified to pull on a cable instead of pushing on a master cylinder ......

With the engine pushed into place, the amount of space both at the front and in both wheel arches could be assessed, at the front there was enough space and plenty in the wheel arches despite not yet having the hubs/brakes fitted. With the increase in performence the brakes had to be upgraded and with the desire to maintain the 10” wheels it had to be either cooper s brakes, very expensive, or try the fiesta calliper conversion, having been given some fiesta callipers there was no contest really, quite an easy conversion with some elogating of the mini hub calliper mounting holes, use of metro drive flanges and getting the 8.4” disks turned down to 7.9”, the brakes upgrade was one of the easiest parts of the project. Remember that the fiesta callipers are metric and mini brakes imperial at this point, i used transit flexible brake hoses to join up to the imperial mini system.

With the injection engine an electric fuel pump is required, also as a constant fuel pressure is required the excess pumped fuel is returned to the tank, therefore not only is a pump to be fitted but also larger diameter fuel hoses and an extra fuel line to return excess fuel to the tank, the standard estate fuel tank has a fuel diameter fuel take off point which is too small, therefore braised two pipes into the tank, a take off underneath and a return in one side, it was very hard to find a suitable place due to the rear valence and subframe obscuring most parts of the tank. A lot of heat was required to braise the pipes in, a tough job requiring several blow torches at once.

The hubs were added next and driveshafts installed along with new oil seals and cv gaitors. The driveshafts were supplied with the engine so didn’t have to make those. Not that hard though as done them before for the vtec mini.

Before the frame/engine could be fitted permanently the gear linkage and engine mounts needed to be sorted out, engine mounts wise after several attempts i got a metro rear engine mount from the scrap yard and fitted that to the rear of the subframe along with a stabliser bar half way up the back of the engine and left and right hanging mounts. This took a lot of time but is very important to prevent movement of engine and noise if it rubs on anything etc.

The gear linkage was very hard, numerous attempts at getting this correct were needed, decided to weld the linkage mounting pivot plate to the subframe to add some strength as it was a bit flexible down the back, added more subframe bracing at the rear as relying on the frame floor mounts being strong.

The exhaust unfortunately fouled the front subframe crossmember and a chunk needed to be removed so I knocked up a replacement chunk that hangs underneath (only available space) the exhaust to replace the missing strength, seems to be pretty strong and makes a handy jacking point.

Now the subframe is ready to mount in the Mini, another job that took longer than expected trying to get the mounts lined up, once done though the engine is in for good, hopefully not to be removed for a while.

Next came the brakes, with the addition of the disc brakes, it makes sense to fit a servo also, a remote servo can be used with the conversion to single line brakes required by the fitment of the small master cylinder. Initially I used the existing Mini bulk head mounted pressure regulating/failure valve but after numerous attempts to bleed the system failed I eventually ditched the valve and replaced it with manually adjustable brake proportioning valve, this worked instantly and I never did find out why the existing valve wouldn’t work.

Next the front of the subframe needed some brace bars to give it some extra strength, again another job that took quite a while to do as they fouled the flexible brake hoses but the front of the subframe has nothing else supporting it so brace bars must be fitted to prevent flexing at the front.

Without the front tear drop mounts there was nothing to hold the front in place so made various brackets to attach the front to the front crossmember of the subframe, seems nice and strong now.

The exhaust fouled the gear linkage that i mounted centrally in the tunnel but a piece of flexible exhaust allowed a bend to be put in the exhaust to clear the gear linkage, welded the flexible pipe to the downpipe and then clamped that onto the existing RC40 exhaust system.

The space for a radiator was small but the Nissan Micra rad fitted in nicely, fitting a fan however was a lot more difficult and in the end the only fan i could get in there was a motorbike one, whether this is enough for summer use, time will tell, may end up fitting an additional rad and fan somewhere else.

The temperature gauge of the Mini dash is meant to use a mini temp sensor and not a metro sensor so knocked up a pipe with a 5/8” UNF fitting in it to allow a Mini temp sensor to be added to the pre-thermostat water pipe.

As the water needs to be circulated around until the thermostat opens this was fed through the heater, as it would have been according to the metro haynes manual, seems to work, rad stays cold until thermostat opens.

Another issue was wheels, sticking with 10” wheels meant having to buy a new set of alloys that had a very flat inner surface to provide clearance on the fiesta callipers.

The throttle cable got left until almost last and proved to be very hard work due to the fact it needed a throttle switch fitting to the pedal itself and the Mini cable was too short so got an extra long metro cable and modified the throttle pedal to include a switch and a return spring to ensure the switch closed when foot was lifted off the pedal. The ecu won’t control the idle speed properly without the throttle closed switch.

Another important factor is suspension alignment, having a set of tracking gauges helped a lot but setting the castor angle was still difficult, however not impossible by measuring the camber angle at a preset + and - 10 degrees steering angle from centre, from these measurements castor angle can be calculated. This is important to know how to set the adjustable tie bars such that the car will steer evenly left and right.

The disc brake conversion has pushed the wheels out by a couple of inches and it now requires some wheel arches to make it legal, so a set of chrome arches were purchased from stafford show 2008.

Finally after starting in October 2007, the completed k-series transplant hit the road in early February 2008, a very satisfying drive, quite, nippy, nice throttle and clutch feel, a few teething problems but otherwise great :-)

So, in conclusion a large undertaking, lots of highs and lots of lows, here’s a quick recap of the highs/lows:

Highs:

finally getting started after many months of no progress, getting engine to run for first time, getting frame to fit car, first drive :-)

Lows: (lots)

not being able to get the brakes to work after hours/days of trying, spending hours and hours on trivial things appearing to make no progress, thinking the project would never be finished, having the car fall off the ramps!, luckily no damage :-)

Teething problems:

forgetting to tighten wheel nuts and getting a knocking noise when wheels came loose :-(,          

running low on petrol which seemed to wreck fuel pump followed by actually running out of petrol and having to push 100 yards back home:-(

idle speed rising to 2000rpm as ecu finally gets ‘up to speed’ and starts controlling the idle speed.