valve adjustment

I pasted above an image of the four-cycle engine from Wikipedia because it helps me think about it. The four cycles are 1)intake, 2)compression, 3)power and 4) exhaust.  The piston is at TDC twice — between exhaust and intake, and between compression and power. The intake valve opens for the intake stroke, and the exhaust valve opens for the exhaust stroke. You want to adjust the valves when they are both closed.  Both valves are closed for the compression and power strokes. You want to adjust them at TDC between compression and power.

In two revolutions of the crankshaft each cylinder fires once, so with a 3-cylinder you get 3 fires per 720 degrees, or a fire every 240 degrees. So once you find the right TDC on one cylinder turning the crankshaft 240 degrees gets you to the right TDC for the next-firing one.

Please make sure you have fastened the kill switch so there is no possibility of the engine starting while you turn it by hand. 

Don't look at the pulley, when both valves are closed set the valves on that cylinder. Then rotate the crank and do the same on the cylinder with the closed valves. Rotate the crank and do the last cylinder. If the valves are closed the piston is at or near TDC no matter what the pulley mark says unless someone tore the engine down and failed to correctly time the cam. 

You haven't torn the engine down have you? Was the engine running before you started doing the overhead? Are you sure your turning the crank in the correct direction?

I believe the glow plug goes into the precombustion chamber from which there is no direct entry to the piston. 

For many years the way I have set the valves on engines is by rotating the crank until both valves are closed on a cylinder and then setting the clearance. This never has failed to do the job. 

It's been years since I set the overhead on my tractor but as best I remember I ran into the same issue you have, the pointer didn't line up with TDC when the valves were closed. When I realized that I just used my tried and true method of setting the valves and it worked. 

Thinking about it now, I remember spending several hours trying to figure out why TDC didn't end up with the valves being closed and finally gave up. 

If the both valves are closed on a cylinder then the cam is on the low side of the lift  and the clearance can be set then. It's not rocket science, just do it.

You don't need to be that precise. If you look at the picture I posted, both valves are closed for the whole compression stroke and power stroke.  It's not like they're “more” closed at TDC than the rest of the stroke, the idea is that at TDC you're as far away from either valve opening as can be and there's no chance that one is slightly open when you're doing the adjustment. Being off by 20 degrees is no problem.

it is all gear to gear in the front of the engine there is posts and pictures on the site showing how things are timed and marked on the gears

And whatever you do, Don't screw with the injector timing!

dogdoc,

It is important to break loose those bolts before re-torquing.

Over time, heat, paint, etc will 'freeze' the bolt heads (and to different degrees).  To be sure that they are all torqued correctly and equally, they should each be broken loose and retorqued.  Do them one at a time so you don't disturb the head gasket.

RonJ