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Failed Valve Adjustment Procedure

As you may reacall, 93 1500 350 TBI issues. Engine idle nice, hesitates under load, poor power.

Well, I tested EGR and PCV valves, installed fuel filter. No change. I got to thinking and reading that perhaps the valves needed to be adjusted. I think th eduel pressure is fine. I trying my best to hold off on dropping the fuel tanks and pulling the pump. I can here it buzzing for two seconds when I turn the key.

So I adjusted the valves again. After the adjustment, the truck would not start at all. What the #&@*?

Figured I screwed something up. Went through the entire procedure for valves again. Still wouldn't start. So I went to each valve and loosened the adjusting nut and sure enough she started.

Here's my problem, when rotating the pushrod to feel the lash. I got to a point where I thought there was no lash. I tighten the nut, wait a while and I turned the pushrod just to check and sure enough, there's still some lash left. I had to use a good amount of strenght to turn the push rod by hand, but there was still lash left when I thought I'dtaken it all out.

It's not like that across all the valves, but a few of them sort of fool you.

So, should the lash be adjusted completely out of the push rods or is some resistance okay before I give the nut one last 3/4 turn? I obvislously had the valves tightened too tight hence the engine not starting.

Do you think my valve adjustment could be the reason I'm not getting any power and having hesitation problems. Valves opening to soon or too late maybe?

Thanks for any help.

Brian

Reply to
brianwrites
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Whoa! Zero lash means that you won't be able to move the pushrod "up and down", not that you won't be able to spin the pushrod. When you are spinning the pushrod and you are approaching zero lash, you will feel the pushrod grab slightly. Lift up and down on the pushrod, any play? If so, you need to tighten a bit more....no play....back off a quarter turn and slowly coming back down again.

Whether this will help your other problems, I don't know, but you have to get the valve lash properly adjusted before anything else is done.

Ian

Reply to
shiden_kai

From the sounds of this he may have some bent pr's resulting from the first adjustment.

Reply to
Roy

When adjusting valve lash, (hydraulic lifters), three important points.

  1. Loosen all rocker arms and some how spin the oil pump to pump up the lifters.
  2. Make sure the valve you are adjusting is not opening. In other words, adjust the intake when the exhaust is open and vice versa. Follow the timing order and spin the engine by hand ....ect.
  3. Tighten the nut until there is no free play at the rocker arm. Then tighten (preload) the lifter 3/4 of a turn or so, whatever the book calls for in steps, 1/4 turn at a time. then STOP. After the lifter bleeds down you might be able to spin the push rod by hand, that's ok. If you did it right the barrel of the lifter will be centered in the body of the lifter, which is what you are after.

You can adjust valves with the engine running. Loosen each rocker arm until it rattles, then tighten the nut slowly until stops rattling, then add the preload amount as in #3 above. Then clean up the oil that sprayed all over the engine, on you, the ground.... Good luck

Mike N

Reply to
Mike

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