I rebuilt my engine, changed piston rings, cam bearings, rod/crank bearings, the block and a few pistons. I know the cam was replaced sometime in the last 50k miles, but in not sure about the lifters, pushrods and rocker arms. When I first rebuilt the engine, it was quiet, but I do remember hearing a very faint knock. I left, and my dad drove the car for about 700 miles. Ever since then, the engine has made a knocking noise. It's not super loud, but noticeable. It seems to be half the frequency of the crank meaning something top end.

I can hear the noise warm and cold, and it seems more prominent when the car has been driving for awhile. At middle temperatures, and sometimes when cold, I can barely hear it. When revving above 1.5k I can not hear it. Sometimes when the car is cold revving makes it a little louder until 2k where i cant hear it.

It sounds like it is coming from the center of the engine, and I can hear it louder from underneath the car nearer to the back of the engine. I know I do have an exhaust leak, but I doubt it is causing the noise. With a mechanics stethoscope I can hear the knock, and it might be slightly louder on the drivers side, but Its hard to tell. Seems to be a similar volume near the back of the engine from the top rocker covers and bottom of oil pan with the stethoscope.

Here is a compilation of some recordings mostly warm.

When starting stone cold, putting the car in gear and revving a little I can hear knocking

I took off the drivers side rocker cover, the arm on the very end moves side to side (towards front and rear of car not with rods and valves) and makes a noise. It is stiff with in the direction where it makes contact with the valve and pushrod. The arm on the other side does it a little bit, and the rest are dont.



I drained some oil by taking off the filter when I replaced a seal today and noticed the oil was a little glittery. Is this normal since I just rebuilt the engine, or is it eating itself from the inside? Note the oil was already changed once since the rebuild.




A magnet picked up a few bits.



What could this knock be? A sticky lifter?

 

Sounds like a classic slipped liner noise, but it could be something else. To rule out other issues check the oil pressure, low at idle can cause the top end to tick and will go away with revs. Also get that exhaust leak fixed, shop vac or leaf blower in the tailpipe.

 

Sounds like a slipped liner to me as well.

 

The sound is deeper that a lifter, but silver in the oil is a bad sign.

 

Do the slipped liners also make noise when cold? I hear knocking when cold, but it seems louder when warm. Maybe its just easier to hear when warm since the exhaust leaks seal up.

Can the silver in my oil just be there because things are still breaking in since my recent rebuild?

 

Could be