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MG MGB Technical - Interchangable Cams??

I would like to increase the performance in my 78 MGB by replacing the cam with a more aggressive one. Since, a new cam from a parts supplier (eg. Moss) is $250+ US, I am curious if another cam could be substituted. I know that the same basic engine from the B was also used in many other cars. Did any of these other cars have a more aggressive cam? Or, am I limited to watching for sale prices?
Please help.
Andrew Turner

Andrew. Not exactly sure what you are asking. The basic question, "Did anyone else use the B series engine with a cam offering more performance than the factory cam?" come through clearly. What does not come through is why you think there might be a less expensive altenative available. The chrome bumper cam will drop into your engine with no problems. Will also give you a chance to go to a duplex (two row) timing chain and gears. Also replace the tappets while you are at it. Using a new cam and old tappets is false ecomomy. So, the cost of a new cam and tappets is about equal regardless of which cam shaft you want to use. The least expensive cam may well be the factory chrome bumper cam. No cam worth having is cheap. Cams may, if they are in good condition, be reground. This is slightly less expensive than a new cam. Most experienced builders would rather spend the money on a new cam than a regrind. Used cams and lifters should not be installed in any car you intend to keep. Most of us are not competent to examine a cam and tell how much remaining life it has, nor do we have the professional equipment to guarantee that each lobe has worn exactly like all of the other lobes and that the who thing is in balance. Hence, anytime you put a used cam and lifters in, you are conducting an experiment--one which may or may not work as expected. You are much better off starting to build with new parts. You also need to look at other modifications so that you can take advantage of any cam changes. Everything must be balanced. A more effective cam with a Z-S carb on the original intake/exhaust manifold is a waste of time and money. A set of headers or a pre-75 exhaust manifold, combined with some exhaust system changes is a very good place to start. Then go to an earlier intake manifold and twin SU carbs, properly needled for power and with K&N filters (or a Weber DGV series carb setup). These two changes alone will give you far more increase in power and performance with your current cam than changing the cam and leaving the intake/exhaust system stock will. It will also provide you with a building foundation for in improved engine if you want to work on it. Les
Les Bengtson

Andrew: The Piper BP270 cam is just what you're looking for. As Les notes you do need to use new lifters and a carb change is needed if you still have the Zenith. Call Brit-Tek parts at 1-800-255-5883, speak to Bob about your needs and ask him to send you a free catalog. The Piper with a Weber or SU's will really make your late model B come alive.
Terry D

Andrew, When we rebuilt my 67 B/GT engine this spring we put in a "performance road" cam, which according to the Bentley shop manual lies somewhere between what MG called a "half-race" and a "full-race" cam. Cost about $100.00, with my core, from Northwest Imports in Portland ,Oregon, USA. Will hold a good, if lumpy idle and does go much smarter than the original ( I say this having owned 3 prior Bs) Would certianly do again, also fully balanced the engine, new pistons and much else.
Kenneth von Wolf Lewis

This thread was discussed between 11/12/2001 and 12/12/2001

MG MGB Technical index

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