Valve Adjustment

[Anonymous]

1965 200 I6
I had a lifter tapping so I decided to fix it tonight, I went ahead and
re-adjusted all of them, my question is I noticed that on the 4th and 5th cyls. the valves were very senseitive, just turning the nut an 1/8 to 1/4 of a turn would stall the engine untill it died, is this normal? The rest of the cyls. would recover just fine during adjusting.
The engine has recently been rebuilt (less than 100 miles) the head was reworked also.

 

[Anonymous]

Sure would like some input on this.
Thanks

 

[Anonymous]

I assume your using hydraulic lifters with the earlier adjustable rocker assembly.
Take a look at the adjustment on those rockers.

on the 4th and 5th cyls. just turning the nut an 1/8 to 1/4 of a turn would stall the engine

If the adjustment screw is all the way down you might have collapsed a lifter. The reason I say that is because the symptom your describing, the valves being

very senseitive

sounds like how solid lifters behave. It would be odd for more than one to collapse at a time, unless they are real old, or over adjusted. Normally the hydraulic lifter gives you a much more gradual feel.

 

[goinbroke2]

One of two things,
1) You didn't back off enough.(when the rocker is loose enough to click, the lifter is pumping up). You must back off the adj, let it click a couple times, then slowly take out the slack, and add however much you want. Otherwise the lifter is almost bottomed out and when you start adjusting, you bottom the plunger and float the valve stalling the engine.

2) You have a couple of bad valve springs. This is more for perf cams, but if you have aggressive ramps and weak springs, what happens is the valve is easier to open than compress the plunger in the lifter.

3) Gummed up lifter. The ports in the lifter won't allow the oil to bleed out because they're gummed with varnish/shellac/etc.

Ok...3 things...

Actually something else I just thought of, since the engine is just rebuilt, #2&3 shouldn't apply unless you put in a perf cam with stock springs.

I would guess backing out the adj until it clicks a bit then readj will fix it. If the head was redone(valves ground) check installed height on the two "problem" valves and then compare to the rest. Somebody while grinding the seats might of sunk the valve and not made up for it with valve shims. Or if you have an on-head spring pressure checker, use it.