MM Carb spacer

[pgc520]

Does the MM engine have a spacer between the Carb and the manifold ? as shown in the picture below, as some cars seen to have one fitted and others don't. Any thoughts greatly appreciated. Thanks Andrew[frame][/frame]

[DAVIDMCCULLOUGH]

They didnt come with one originally. I had major overheating/ fuel vapourisation issues with mine and a spacer was one of the things that helped to sort it out. Mine was made from an old peice of asbestos from an ironing board! I checked all the MMs with bonnets open at Stanford Hall and most of them had one fitted.

In addition to the spacer I fiited a later carb with the float towards the front of the car, not 1' away from the exhaust as standard and also re routed the fuel pipe accross the gearbox and then along beneath the battery box.

[mike.perry]

The carb spacer was fitted to the USHM3 engine to overcome fuel vapourisation caused by heat from the manifold reaching the carb. The close proximity of the fuel pipe to the exhaust pipe was another contributing factor which resulted in misfiring and difficulty in re starting in hot weather. The spacer was made from heat insulating bakalite.
Owners of cars with the earlier engines who have fitted spacers and moved or insulated the fuel pipe have noted a great improvement in the running of the engine in hot weather