I just wanted to verify a sound that I am hearing that I never noted before.

This noise can be produced by rotating the engine by hand a few degrees and then stopping. The sound is a snapping sound, is decent in volume and, appears to be emanating from the heads.

At first, I thought this was heat related- similar to an engine that is heating up or cooling down where things are expanding and contracting. However, I was able to reproduce this by rotating the engine a few degrees by hand. That rules out thermal expansion.

The duration lasts a few minutes and then stops suddenly.

Questions: is this normal?
Is this compression related?
Has anyone else noted this?

Thanks,

CM

 

sticking valve?

 

by hand.?... Well if the motor is not runing the oil pump is not moving oil and not pumping up the lifters making the lifter weak pushing the push rods so ya push rod to the rocker noise

That my guess

 

can you hear the sound when its running?

 

there is still a spring in the lifter. if there is a big enough gap between the pushrod and the lifter to hear a snapping noise, then there is another issue entirely. there should always be preload on the lifter. the only way that a gap could occur, is if the valve is sticking open when the cam is on the cosed side of the lobe, then the valve spring breaks whatever is making the valve stick, it will slam shut, making a snapping sound.

 

Can you load an audio file of what it sounds like? I wear glasses and I can't hear it very well.

 

It does not make the sound when running. She runs mint. However, after changing the intake, timing chain, water pump, oil pump, fuel pump, plugs, intake, TB and more, I just started to hear this sound.

It goes on for some time in the same spots. It sounds exactly like when the exhaust heats up. Same kind of sound. It doesn't just do it one time but, many times over and over.

I also changed oil filters to K&N vs. FRAM or Bosche and am wondering what the flow rates are for K&N oil filters. I recall years back there was an issue with lack of oil flow due to oil filters that filter down to the micron level. It restricts oil flow to the point of the oil filter oil cans out and blows apart. Again, I am not saying that the K&Ns do this but, it's something I did not check either before putting it in.

When warming the engine and shutting it down, it also makes those sounds for a period of time. It sounds like something dripping at a fast rate and slows down over time. This is why I am now thinking about the lubrication aspect.

Let me see about recording the audio and then uploading it to Y-tube.

PS: When I had the intake off yesterday, I checked all pushrods and all were under pre-load. No play