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MG MGB Technical - Engine identification without data plate

I'm sure this is in the archives but I can't find any direct matches. If the engine data plate is missing on a MGB engine, how do you identify an early 18V from other engines? Thanks.
jim dunn

Jim-
The quickest way to spot an 18V engine is to look for a trapezoidal blanking plate just beneath the front tappet chamber cover on the carburetor side of the engine block. This is where the mechanical fuel pump for the Marina was mounted. This feature is found only on 18V engines. If this feature is present, you can tell if it's a very early 18V by it having a duplex camshaft drive chain. All of the early 18V engines had SU HIF4 carburetors and an intake manifold with a vacuum take-off. Early 18V engines should have a head casting number of 12H2923 on the top of the head (under the rocker cover).
Steve S.

Jim. The best way to distinguish between the early or late 18V engines is to pull the cylinder head and look at the top of the block. The early 18V used a bigger exhaust valve and has a relief cut at the top of the cylinder. The later 18V used the original sized exhaust valve, but kept the cut out. The difference between the early and late 18Vs may be the motor mounts. The RB cars had a significantly different mount than the later models, but I do not know if the block changed. Les
Les Bengtson

This thread was discussed between 30/12/2001 and 31/12/2001

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.