Tuning British Leyland's A-Series Engines by David Vizard

Octagon Newsletter April 1986

Book Review by Phil McOrmond

I read an interesting book that might be intriguing or even useful to those members who have reason to power their cars with the Series 'A' motor.

This is a large and comprehensive text, but it is not a beginner's manual on how to assemble an engine. This will not show you how to put your assortment of pistons, rods, and valves together to make an engine. For that you will still need your Haynes manual or shop manual.

Vizard sets out in the introduction to make this the bible for the engine and in most regards, it's certainly the most comprehensive text on tuning the engine I have ever read. The book covers the engine from water pump to output shaft but nothing beyond.

I realize that some of the other club members are devoted to 'originality' at all costs, but even so, this book would be a help, as many modifications are internal and, as such, would not alter an otherwise stock-appearing engine. Of course, if a very hot road set up or full race engine is desired then a stock appearance would have to be sacrificed.

The layout of the book starts with the history of the engine and proceeds to the basic description of horsepower/torque and what goes into the making of the same. All subsequent chapters are devoted to air flow.

Vizard appears to have flow tested almost all components and modifications to determine what works and what doesn't. Some of the old standbys he lays to rest. He does not believe in polishing combustion chambers, unless you like the exercise it provides! Nor does he believe that multiple carburetion or balancing is the way to go. In the carburetion section, he points out that a single 1 1/3 SU provides more than adequate air flow up to 75 h.p. and is a lot easier to tune than multiple carburetion. I don't personally advocate this system as I think half the fun of an owning a MG is adjusting the twin SUs (the other half is talking about how they're not quite right!).

Vizard spends several chapters on valves and head modifications and this is interesting reading if you plan a valve job in the near future pay special attention to the section on re-inflow valves if you haven't heard of them before. These valves have a small raised rim around the edge of the valve that encourages one-way flow of gases. According to Vizard, this has the potential of improving power under full throttle and economy under part throttle.

The section on camshafts covers all the 'BL" ones plus several others most of which are either made or available in the U.S. The only problem with the high powered cams is that they start to reduce derivability of a street car long before ultimate power potential is obtained. What would be acceptable in a race car is not 'OK' in a street car.

There are sections on the new series A+ (MG Metro) engines, but as these are only for transverse applications, their interest value is limited. There is also a section on turbo-charging.

In conclusion, the book is a good one well written with good photos and reasonably clear graphs (if a little busy). Required reading, I think for any series 'A' engine owner.

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