The 'Gospel according to Calver' concerning all tuning carried out on any aspect of your car and therefore the most poignant sentence to remember when planning your campaign of modifications. 'Tuning should be a compromise between what is possible and what is necessary' Committing this to memory will increase the enjoyment and fun factor by having a car that can be driven very quickly yet have maximum reliability. After all, frustration, disappointment, and depleted funds have condemned more projects and race cars to the scrap heap than practically anything else. Read more

Since there is already a very good source of starting points/applications for fixed needle carbs, this is for those floundering about in the wilderness that is the biased (swinging) needle example of the breed.

Unfortunately I cannot give an all-encompassing table of what needles are needed for which engine builds. My life's collection of all the automotive-orientated work I'd ever done was stolen out of my car by some low-life scum a few years back. Not for what it was - but for what it might be. All I have is a few scribbled notes, the source of where I start now. Being an oft-voiced question on the message board, I thought I'd share it with you. Since there is already a very good source of starting points/applications for fixed needle carbs, this is for those floundering about in the wilderness that is the biased (swinging) needle example of the breed. Read more

Basic knowledge Even though the SU carburetter (carb) is a very basic yet precise instrument, some fundamental understanding on just how it works is needed to be able to deal with common problems and tuning. Following is as basic a description of what's going on that I can manage! First you need to be comfortable with the main aim of any carb - to supply the engine with a finely atomized fuel/air mixture in the right strength for all operating conditions. This means from idle to flat out and everything in-between. All carbs achieve this using the same method - a venturi or choke (restriction) is used to speed up the velocity of the in-coming air to create a reduction in pressure. This is used to draw fuel from the float chamber via a suitably sized jet hole into the air stream, and hence into the engine. The perfect carb will supply the engine with optimum mixture for both maximum power throughout the full throttle-angle range (variable restriction - as in butterfly and spindle) and minimum consumption under all part-throttle conditions. Read more

On some HIF carbs, the vac take-off sighted just after the butterfly - that's between the butterfly and the carb to manifold mounting flange - has been eliminated. Instead, the engines these carbs are fitted to use a vac take off in the manifold. The reason for this is again wholly idle emissions orientated. The higher vacuum that exists in the manifold area can be used to pull more ignition advance. Theoretically this will reduce emissions at idle. Unfortunately it's exposed to induction pulsing. In the A-series, this is UGLY. The pulsing and high manifold vacuum causes rough idling. Particularly where anything 'sportier' (ANYTHING) than a bog-stock-standard cam profile is used.

Classic example - the MG Metro. Its adventurously sporty cam makes for a slightly lumpy idle. This increases idle speed emissions, so Rover use manifold-sourced vacuum to increase idle speed ignition timing via the vac advance. Read more

Although there are a number of different versions of the HIF type carb, they all essentially share the same type of connection layout.

The diagram below depicts the most common type - the connections can be on either the right hand side (as illustrated below) or the left hand side. Some have the connections shared on either side. Whichever, the port functions are the same. It isn't essential the crankcase breather pipe be connected - you really don't want that choking crap from the crankcase spoiling your nice, fresh, fuel-rich incoming mixture - but it's obviously essential to block the port off if you don't. A blob of RTV Silicone is sufficient in most cases. To adjuster mixture - screw the adjuster in to richen, out to weaken. There may be a 'anti-tampering' cap in there on some carbs - just hook it out.

Firstly - re-runs or re-hashes of technical literary prose always brings to light either new, or old forgotten subjects for close scrutiny/re-examination. The arrival of 'A Well Known A-Series Tuning Bible' is no exception. Good news as far as I'm concerned as it keeps me gainfully employed!

This dissertation is centred upon that old chestnut 'ignition systems'. Technological advances running through the entire automotive world hasn't ignored the system that supplies life-giving sparks to bring your engine alive. It's true - no spark, no power. Much of the technology applied has been about making bigger, fatter, longer lasting, and more consistent sparks. The plethora of Mini spares suppliers have embraced this whole-heartedly as it's another string to their bows of profit generation. And it's this that's causing the problem - again Mini owners are being sold stuff that they don't need, or more pointedly will NOT increase power out-puts one iota. Read more

I have been using the Ignitor ignition systems for some 8 years or so, as long as they have available in the UK, and have never found fault with them nor had any reliability issues. Until the beginning of this year… A new customer for this year, racing an MG Midget here in UK under a limited mods category, was doing splendidly for the first couple of races, then started experiencing a misfire. Initially it was believed to be a fuel starvation/vaporization issue. All fuel pipes were checked and re-routed where it was considered necessary. Those still considered in danger of getting too warm were heat shielded. The misfire persisted. On to the ignition system. All was checked, but then a loose alternator wire was found and blamed for the fault. It wasn't. Back to the ignition system then. Read more

I'd like a pound coin for every time I've been asked about what these are all about and why they are used. Folk seem to hold them in some kind of awe - but they are very simple. The ballast resisted ignition system was - I believe - developed by Ford when they were experiencing poor starting on a certain prodigiously-used 4-cylinder engine. To get round the issue of the massive current drain caused by the starter motor functioning, the ballast-resisted system was designed. When you hit the starter button/key, a massive drop in available current to the coil occurs as the starter motor does its thing. The colder the weather or the more worn the starter motor, the more current it draws, the less there is passed to the coil to instigate ignition. Read more

The advent of ECU-equipped fuel injection saw the need for a trigger system to provide the ECU with information on engine speed and piston position. In their infinite wisdom, Rover decided to fit a reluctor ring into the rear of the already humungous iron flywheel section.

Identical in all aspects to the non-injection flywheel except for this reluctor ring and the raised ridge it is fitted into. It weighs a little more than the non-injection item, but can be fitted to non-injection pre-engaged starter endowed cars should the situation deem it necessary. But ONLY the flywheel - NOT the diaphragm (see 'Pressure plate - Verto types' for further details). Consequently the same in-effective non-cost effective limited lightening can be carried out to the standard item.

Identical in all aspects to the non-injection flywheel except for this reluctor ring and the raised ridge it is fitted into. Read more

A subject worthy of an entire book to explain the whys and wherefores, and also causes much consternation on the part of the transplanter. Terminology - BBU - Big Bore Unit SBU - Small Bore Unit FD - Final Drive (diff ratio) A subject worthy of an entire book to explain the whys and wherefores, and also causes much consternation on the part of the transplanter. Much confusion’s spread over which gearbox has the best ratios, is best to use, and with which FD. For a detailed account on this and covering all gearboxes fitted as standard to the Mini, see the relevant separate articles 'Gearbox - Standard production gearbox types'. Fortunately, when selecting a complete engine and gearbox unit from a Metro, the gearbox will pretty much suit the engine and be easily transplantable whole into the Mini. It shares exactly the same rod-change linkage as the Mini. Difficulties only arise when fitting a rod-change gearbox into a pre-1973 Mini that has the old remote-type gear-change mechanism, but not insurmountable. It's dealt with in the 'Ancillaries' appendage to this series. Read more