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MG MGA - 18V-836-Z-L block in MGA

I recently purchased an 18V-836-Z-L block to rebuild to replace a 1500cc engine. I am aware of some of the challenges i.e., with the rear plate, flywheel and starter. But a note about early engines not fitting in rubber bumper cars in P. Burgess' book and now in the tuning article on the sterling British web site:

"Be aware that the later 18V blocks from the 1975 through 1980 Rubber Bumper models have a repositioned motor mount boss on the camshaft side of the block and so will not fit into earlier cars. These can be readily identified by their engine numbers:
18V-836-Z-L, 18V -837 -AE-L, 18V797-AE-L, 18V-798-AE-L, 18V-801-AE-L, 18V-802-AE-L, 18V-883-AE-L, 18V-884-AE-L, 18V -890-AE-L, 18V-891-AE-L, 18V-892-AE-L, and 18V-893-AE-L."

has me worried.

What is the issue and is there a "work-around?"
V. H. Brown

V.H. To the best of my knowledge, this refers to the switch to the round type motor mounts as opposed to the square type motor mounts used in earlier cars. The later model Rubber Bumper Bs had a steering shaft which went throught the left hand motor mount. Earlier models had a steering shaft that went over the motor mount. The solution would be to custom fabricate a mount going from the engine, bolting into the block and onto the front plate, having a provision to bolt up to the MGA motor mount point. I have not done this myself, so my observation may not be valid. However, I have done a great deal of fabrication and modification over the years and do not see this as being a problem which cannot be over come. Les
Les Bengtson

Thanks, Les. I believe I have found the answer on Doug Jackson's site: later engines need to use the front plate from the earlier engine.

Just to add to the confusion the engine mounts on my 18V-836-Z-L engine are rectangular and the front plate looks identical to that on my 1500.

Thanks again,
Sandy Brown

V. H. Brown

Sandy. The markings on the side of the engine are, after this many years, only a general indicator. A totally original, non-rebuilt engine is rare. It is perfectly possible that the engine was rebuilt for use in an earlier car and the front plate was changed as a part of the rebuild process. Les
Les Bengtson

I am confused by the statement in Peter's book and the one above.

The RB engines ahve a different front plate which is easily swapped, but the reference is to the boss on the block.

Early engines have blocks with an oil gallery that runs forward to the engine mount "cutout" (not really a "boss" at all), later engines have the oil gallery trerminating half way down the engine and a aperture for a mechanical fuel pump sits behind the engine mounting point.

Both types of block accept both types of front plate and the associated engine mountings and therefore any block can be used in any car!
Chris at Octarine Services

This thread was discussed between 01/04/2005 and 04/04/2005

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