manych

I just swapped out my cylinder head on my 89 w250, everything went smooth until I started it, ran real rough. I think the problem may be when I set the gap between the rocker and the valve spring, the thread I was reading said to set the gaps but didn't say anything about top dead center, so basically all the valves would be set closed right? im not sure what to do from here
ive never tried a job this size before and im a little overwhelmed. any help would be great.

maybe368

Basically the valves need to be on the flat part of the cam lobe, completely closed, in order to set the valve clearance. If you did not do that, the valves are badly out of adjustment and you should not run the engine anymore, until they are set right. There is a danger of interfacing the valves, with the piston or the other valve, if they are badly over tightened...Mark

j_martin

The easiest way to get it right is to rotate the engine so each cylinder is at TDC between the compression and power strokes. The interesting thing is that at TDC between the exhaust and intake strokes, both valves are slightly open. We can use that to our advantage.

Firing order is 1 5 3 6 2 4. When both valves of #6 are moving, #1 is very near TDC, lined up for adjustment. Set the valves, then rotate the engine so #2 has both valves moving, (It will be exactly 1/3 of a rotation) and adjust #5, etc till you've set the valves on all 6

hope it helps.

manych

im a neub at this stuff, when you said set 6 and check 1 were you referring to the firing order or the cylinders counting from front to back?

maybe368

Here and here
are the 2 how-to's in the sticky. The second one involves using a barring tool to turn the engine, the other uses the alternator pulley. The instructions are pretty easy to follow...Mark

manych

Thanks for the help! I'm back on the road!