[vicg1]

Like many people post here, I have a tapping noise.

Background: engine dead because prior owner drove it with no coolant. Radiator had a crack. We pulled the engine, stripped it, everything looked great. No sludge.

Had heads redone, including some straightening and reassembled it all. We did not replace the chains/guides/tensioners because wear looked minimal, tensioners were not fully extended, and the set is expensive!

Fast forward, engine runs smooth, no codes, but we do have a tapping noise. Stethoscope doesn't help much, but it seemed like sound was from drivers side front tappets...

Pulled valve cover, replaced a few tappets, noise still there. Again stethoscope doesn't help much. Pulled pass side valve cover, still sounds like it's the drivers side... sound radiates thru timing chain passages but does sound like it's the drivers side.

Going crazy here. Don't feel like pulling engine again, thinking of driving it until something actually fails.... not the pollution valve or exhaust...

Thoughts? Could a rocker be bad even though visually nothing looks wrong?

 

[Frango100]

Welcome to the garage.
So your engine is the 4.7 V8.
Did the hydraulic lash adjusters you replaced feel spongy? When you feel them now in the engine, is there any spongy. Could there be a problem with the oil feed towards the lash adjusters. You checked the rocker arms, so there is not that much what can go wrong with them.
Did the engine run for at least an hour, to be sure that all air is purged from the lash adjusters?

 

[vicg1]

Thanks for the welcome, been here reading for a few months now.

Sorry, yes 4.7. The lash adjusters feel good and strong when pulled out... no shortage of oil. We replaced a few where we thought the noise was from and same thing. The sound radiating makes it tough to pinpoint.

I thought of running it with an adjuster out, one by one, to see if we could isolate the noise but I imagine the removal would result in a major loss of oil pressure everywhere else in the engine... the oil pump was replaced also even though once again there didn't appear to be an oiling issue when the engine first came out.

It doesn't sound like a lower end noise at all.

 

[Frango100]

Instead of removing the adjuster, you could remove both rocker arms of a cylinder and try. I saw a video on youtube where they ran the engine without the valve cover and it was not making a big oil mess. In that way you could quickly do one by one. Ofcourse the respective cylinder will give a misfire and rough idle.

 

[vicg1]

Giving up.

Can't run with rocker removed, lifter will shoot into the air from pressure... going to drive it and see what happens.

1- sound may go away... not likely

2- sound may stay the same...

3- sound may get worse or something will eventually let go... easier to figure out what's wrong this way!

 

[Frango100]

I heard several cases of fallen of rocker arms, but they never related that the lash adjusters where out as well.
But maybe its still some air trapped, give it a try with some driving.

 

[vicg1]

500 miles on it... noise is the same... no better, no worse!