E30 Zone

Does anybody know the correct way to set up the timing on an M40 engine (Auto) after a belt snap, without forking out fifty quid for the correct BMW tool ???

when i changed the belt on my mates M40, i found TDC by putting a screwdriver into a small hole at the back of the engine where the flywheel is. (facing the front of the car, its on the right hand side of the block) you feel around until the screwdriver goes in, then while pushing the screwdriver, crank the engine manually using a 22 socket until the holes in the flywheel line up and the screwdriver goes fully in. that means its at top dead centre. on the camshaft pulley, there should be a notch which will line up with the cylinder head which tells you thats the correct position for the camshaft at TDC. then put the belt on.
thing is, if your belt snapped, your valves will be bent... maybe worse methinks.

ClemQjeronimo wrote:when i changed the belt on my mates M40, i found TDC by putting a screwdriver into a small hole at the back of the engine where the flywheel is. (facing the front of the car, its on the right hand side of the block) you feel around until the screwdriver goes in, then while pushing the screwdriver, crank the engine manually using a 22 socket until the holes in the flywheel line up and the screwdriver goes fully in. that means its at top dead centre. on the camshaft pulley, there should be a notch which will line up with the cylinder head which tells you thats the correct position for the camshaft at TDC. then put the belt on.
thing is, if your belt snapped, your valves will be bent... maybe worse methinks.

That may not work, due to the fact that the car is an auto. The last M40 auto that I tried that with had many diferent position that I could fit the pin in.

Have you had a look for a mark on the crankshaft?

You could try the old fasion way of taking No.1 spark plug out then putting a long thin object in, and then turn the crank to see when it pushes out fully and then it will be at TDC.

BTW I also think that the valves might be bent.

i bought thr m40 cam locking tool and crankshaft pin from gsf as a set for under a tenner