98 ranger with the 3.0 engine
The compression was 30 on all 3 cylinders on the passenger side and between 140 and 150 on the 3 on the other side. From what I have been told so far I am thinking that too much material was taken off the heads and now the valves are not seating completely. What is your thoughts on this?
that is a possibility. there are other possibilities too.
a quick lesson on lifters.
they are hollow and have a cap in the top that can be pushed down into the lifter.
there is a spring inside that pushes the cap to the top. it is not an overly powerful spring. the pressure from the valve spring goes thru the rocker and pushes the pushrod down which pushes the cap down inside the lifter. the lifters fill with pressurized oil, enough pressure to push the cap back to the top.
at that point there is an equilibrium between the spring and oil pressure pushing up, and the valve spring pushing the rod down. that usually results in the cap being about .020" from the top, which is about 1/2 turn of the bolt. that's the valve lash. (this is a short version, details are missing)
the pressure keeps the lifter full, the holes in it are small enough to prevent the pressure from bleeding off too fast and collapsing the lifter.
so, if you don't have oil in the lifter it won't open the valves all the way.
to check the valve lash:
lifter on cam lobe on base circle, not trying to open valve.
loosen rocker bolt until pushrod is loose.
now do 2 things at once:
rotate pushrod while slowly tightening the rocker bolt until the rod no longer spins, as in contact is made. now count the turns as you slowly keep turning the bolt until the rocker is tightened down. you should have only had to do between 1/2 and 1 turn. anymore and the pushrod is pushing the cap too far into the lifter.
I think shims are available to raise the rocker pedestals to get the lash dialed in.
you can test the cylinders for leakage.
both valves closed
put compressed air into the cylinder, rig something to fit the plug hole.
listen at the intake and exhaust for noise.
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