ohv rocker/rod replacement

[chessman21]

Iv got a loose rocker or broke a broke lifter or something and taping that its allways had gets a little louder when oil level gets bottom of hashmark pre-light low,,, 5w30 rear-main drip. I cant take head off but i think i can remover valve cover.. Question is if its in fact a worn rocker or rod will i be able to feel movement or extra movement in the one thats worn? I know what side but i dont know which cylinder. Should i replace the rod to? If a rocker is damaged is it safe to assume the contact spot on rod is worn as well? Can i replace just one rocker and passably one rod? .

 

[RonD]

Lifters can't be removed with head on, just FYI

Yes you can ID a bad lifter with valve cover off
You will need to put crank at TDC mark
Then try to push down on rockers with closed valves, all should be tight, also try to turn pushrod with your fingers, it should turn but not easily

Then rotate crank one full turn to TDC and test the other valves which will now be closed

A lifter is a cylinder with a piston and spring inside
Spring pushes piston up when there is no oil pressure, or pressure is low.
Collapsed lifter often means spring is broken, so it taps
But there is also a small hole in the lifter that allows oil in, as the lifter is compressed the oil is pushed out but can't get out that fast, this is the hydraulic part of hydraulic lifters.
If the oil hole gets plugged up then oil can't get in fast enough, engine oil pressure is lower than compressed oil pressure, so at that time not enough oil gets into the lifter, so it taps


Oil in the pan(dipstick) between add and full marks does not effect oil pressure, so shouldn't effect the lifter noise
Hot oil is thinner so oil pressure is lower overall after engine warns up.
Higher miles engine should often run 10w40 to keep oil pressure up

 

[chessman21]

Higher miles engine should often run 10w40 to keep oil pressure up

Sticker says 10w30 and iv been useing 5w30 and you say i should use 10w40? pressure gauge reads 3/4 in the good and stays consistent. Tap isnt as bad when engine is hot and even stops momentarily sometimes.

 

[RonD]

Oil pressure gauge should always read the same regardless of actual oil pressure, unless it drops below 6psi.

4.0l all used an oil pressure Switch(all 1988 and up Rangers), switch is ON(closed) when pressure is above 5.5psi, and OFF(open) when pressure is below 5.5psi, engine off hopefully, lol.

In the dash there is a resistor that sets the gauge needle location for ON or OFF
Any movement of the oil pressure needle is a response to Voltage in the dash wiring, not oil pressure change.
So if you have a weak alternator you might see oil pressure needle go up with engine RPMs, but that is electrical not actual oil pressure changing, although is would go up with RPM, hopefully

10w40 just doesn't thin out as much after it warms up so may help with the tapping

How-to here on Ford oil pressure switch setup and how to change it: http://www.therangerstation.com/forums/showthread.php?t=165083

In the later 1990's Ford moved the resistor to INSIDE the gauge so the conversion of the in dash gauge isn't practical, but you could add a "real" oil pressure gauge and use the Sender installed in above article

I am of the opinion you either have oil pressure or you don't so wouldn't do this modification, as long as needle is up when engine is running I know I have 6psi or better

 

[chessman21]

4.0l all used an oil pressure Switch)

Iv replaced that switch and when i did needle went from a steady half to 3/4 with new switch, I dont think my issue is pressure related and its not rod nock. I dont know now,, I know it gets worse when its low on oil. and its been like this for 50k miles, sounds like its getting worse now tho..

 

[chessman21]

low oil louder tap

After adding a quart of 10w30 in the tapping decreased dramatically.. So,,, what does this mean? Rocker or rod or both? I think i read somewere use the same rod in the same hole if removing them.. Hows adding a new in the mix gonna work?

 

[RonD]

When reusing used parts its always best to match them back up, it is not a MUST, it is just a good practice

When replacing parts then it doesn't matter, nothing to match up


Adding oil to pan shouldn't matter for oil pressure, assuming there was enough oil to begin with.
Could mean there is a leaking in oil pickup tube so pump sucks air a bit unless level is high enough, that would change oil pressure.
If increase in oil pressure stops the ticking then it is a lifter issue

If ticking is on the same side as you dump the oil into then could be rocker or push rod on that side, but ticking would come back as soon as all the oil drained down to the pan