Ask the expert
Your Mini questions answered by Keith Calver
DOWN ON POWER
Q I have a 1977 Mini Clubman 1098 Estate, still fitted with its original engine and gearbox. Both appear to be in good condition, with the engine using no oil. However, at anything over 60mph it seems to be working extremely hard. I’ve set the timing as per the workshop manual, and I think the fuelling is right too. However, it’s just gutless. I know it’s not a Lotus, but I don’t remember other Minis being this wheezy. Would some tuning parts help? What else would you recommend? A friend suggested it’s down to valve seat recession, but surely it would smoke if so? Steve
A Before fitting any form of tuning upgrades, you need to make sure what you have is fit and healthy. To do that you need to do a couple of things – get a leak-down test done and if that looks good, get it set up on a rolling road.
The leak-down test is used to determine the health of each individual cylinder. This is done by setting each cylinder in turn on its firing stroke with the piston at top dead centre and both valves closed. A tube with a threaded adaptor at one end is screwed into the spark plug hole, while the other end has a coupling that attaches to an air line so the cylinder can be pressurised with compressed air. The main section of the equipment has two gauges that show the air pressure being applied, and the amount of air being leaked out by way of a percentage. Up to 10 per cent leakage is pretty good, 20 is OK and up to 30 concerning. More than that, and you’ve got major issues. It is not just the gauges that reveal any problems; air heard escaping can lead you to the specific problem. If heard coming out of the carburettor, it’s the inlet valves not sealing. Out of the exhaust, it’s the exhaust valves not sealing. If it’s out of the rocker cover and dipstick tube, the rings are not sealing as they should.
Getting the car set up on a rolling road will optimise fuelling and ignition, and give a power output reading. Whilst rolling roads rarely produce actual and real performance readings, the figures obtained can be directly compared with other similar units run up on it to give some idea of the health of the engine.
Before heading off to the rolling road though, there a couple of things to check and sort. Make sure the ignition system is in good health – so points, condenser, rotor arm, dizzy cap, spark plugs and plug leads. I’d like a pound coin for every engine I have
looked at for somebody for a similar complaint, only to find the plug leads are so degraded they are on the point of stopping a spark getting to the plug!
The other thing to check is the oil – foremost the oil level. I have had a handful of folk come to me over the years saying their engines won’t rev and feel flat, which turned out to be because of excessive oil in the gearbox! It is surprising what the effect of an extra litre in the sump can have. The excuse was usually ‘well, I put extra in because it seems to be getting through it quickly’. No joke.
Q My front seats won’t go back any further as they are hitting the rear companion bins, and this is causing me terrible pain as I drive. Are the bins structural, or can I cut them out? Would I need a rear ‘cage? Maarten
A The companion bins are not at all structural, so removing them will not cause any structural strength to be lost. You just won’t have anywhere to store the sixpacks. Consequently a rear rollcage section is not required. And as daft as this may seem, fitting any sort of rollcage increases your insurance premium as they see it as being done so you can ‘race’ the car. It’s a bit like the issue with fitting winter tyres in the winter – very much a sensible safety move, but not part of the car’s original specification.
The way I have dealt with this in many of my Minis is to make seat bracketry that moves the whole seat as close to the handbrake/car centreline as possible. This allows the seat to be moved back quite a long way without fouling the companion bin.
Q I read a few months ago that a front-mounted radiator was fitted to MPi Minis to quieten them down. I’m trying to create a nice refined Mini using a ‘93 Mini Mayfair as a basis. I’ve already fitted Smootha Ride and loads of sound deadening, so this seems like a good idea to enhance refinement. How would I go about doing this? Can I just fit the brackets from an MPi or is there more to it? Ronnie
A The front-mounted radiator to reduce noise has probably a great deal more to do with doing away with the mechanically-driven fan rather than ‘blocking’ any noise coming out from the engine bay. The test used to determine such noise levels are drive-by recorded by somebody road-side, not in the cabin. It is true a front-mounted radiator is going to be more effective than a side-mounted one as it is in pretty much undisturbed air flow, but it is limited in its capacity because of the available space to fit it in. Whether you need a more capable cooling system will depend on the power capability of your engine. You have not said whether your Mini engine is standard or modified. If standard, or mildly modified, the MPi rad would work OK. More than that it will struggle. The side-mounted set-up has been around so long that some pretty effective radiator types have been developed to cope with some serious performance outputs. Used with the standard plastic fan they do not develop all that much noise
“The side-mounted set-up has been around so long that some pretty effective radiator types have been developed...”
“The result is a greater volume of cleaner incoming charge of fuel and air and so more power...”
that can be heard in the cabin. Consequently I do not consider it a worthwhile change, especially considering all the re-plumbing and electric fan fitment needed to make it operational.
Q I have a 1993 Mini Cooper SPi that I’m considering fitting a new exhaust to. It’s currently standard but with a catback stainless RC40 Millennium system. I’m looking to make the whole thing stainless apart from the cat, including a stainless LCB but keeping the injection inlet manifold. Will I notice an increase in noise by doing this? And will I have problems with the Lambda sensor only sampling from one pipe on the LCB? Roland
A There will be a slight increase in noise going with the stainless steel LCB because stainless steel ‘rings’ more than mild steel does. The shock waves/ pulses in the exhaust system act in a similar manner to tapping the metal. This can be negated by wrapping the manifold pipes in thermal heat wrap. There is a big bonus to doing this aside from damping the noise down, it will improve performance by maintaining the heat of the exhaust in the pipes. This keeps the exhaust gas moving faster, which helps extract more exhaust gases out of the combustion chamber. The result is a greater volume of cleaner incoming charge of fuel and air and so more power. And on top of that, it will help reduce the under-bonnet temperature, which means a cooler intake charge and also helps improve performance. Winning all the way.
As for the Lambda sensor location, as long as it is monitoring more than one cylinder there should be no problems. I believe most LCBs have the sensor boss fitted to the secondary down pipe for the outer two cylinders.
Q When fitting a windscreen, is it better to put the seal on the car and then put the glass in, or put the seal on the screen and fit it to the car as one? Is the string method recommended? Alex
A This is one of those questions that would divide a car-park full of Mini owners. I always fit the seal to the body, then the screen to the seal. I have tried the other way on several occasions to see if there is a benefit, or something I have overlooked. Nothing obvious floats to the surface, other than a real dependence on the quality of the string used. Fitting the seal to the body, then the screen to that really only relies on the pair of hands doing the work, so more of a known factor. I use a couple of strips of masking tape to keep any reluctant-to-stay-put upper seal section to the top of the frame, fit the screen’s bottom edge into the seal, the use a suitable tool to pull the seal out around the screen edge all round. A Snap-On Tools split-pin puller has been ace for this as it’s practically the perfect shape for the job. A little washing up liquid used as a lubricant works very well and is very easy to clean off afterwards.
A rolling road session can help with poor performance.
Retro-fitting a front-mounted rad would be a tricky task.
Can rear bins be removed?
Opinions differ when fitting glass.
A stainless LCB will be slightly louder.