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MG MGB Technical - Crank pulley, timing marks 18v engine

A friend has a 78 MGB with an 18v engine where the timing marks appear way out even though car runs okay - was going to help him establish whether the TDC mark was accurate using a piston stop and degree wheel - my 11" degree wheel wouldn't fit in the space so now looking for a 10" wheel, first problem!
Is the pulley shown in this image the standard pulley used on 18v engines? Also the timing scale is on the bottom of the timing chain cover and only visible from underneath when looking from the rear of the engine. Shouldn't the pulley be like that on the 18GB engine except slightly larger diameter and with timing marks viewable from above?
Mike
Mike Ellsmore

No image there, Mike.
Dave O'Neill 2

Mike,
the rod in the bore with both valves rocking, will give you a good idea of how far out the marks are. But it sounds like the front cover is from an earlier engine (if you are sure it is an 18v).The timing pointer at the bottom, with the slightly larger diameter pulley with marks engraved to suit a pointer at 10/11 o'clock on the cover will explain the discrepancy and the difficulty seeing the marks.
Allan Reeling

Sorry having trouble uploading image - seems to be a problem with BBS server. Will try again tomorrow morning.
Mike
Mike Ellsmore

Here is image of installed pulley and timing marks.
Mike

Mike Ellsmore

Looks like rubber bumper pulley (needs top timing marks) with early cr bumper lower timing marks. You need to mark near enough TDC again. If you are careful with a thin screwdriver you will find TDC within 3 degrees by trial and error and repeat. A note of caution re rubber bumper pulleys, the outer can separate from the inner and give varying timing readings!
Peter
Peter Burgess Tuning

Thanks Peter,
Yes it is on a rubber bumper car. We thought also that the outer may have moved as timing light showed timing way out but car was running okay - maybe time for a Romac balancer! He is looking around for a replacement timing cover with top mounted marks.
Mike
Mike Ellsmore

This thread was discussed between 01/09/2017 and 03/09/2017

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