I am trying to diagnose the cause of a noise my engine makes. I would call it valve noise, but I am not a professional. Let me start with some background and information:

My truck is a 1990, but the engine block, head, and internal components are from a 1992. The prior owner did the engine swap. He also replaced the timing chain at that time. It was his first engine swap.

When I first got the truck (about a 1 1/2 years ago), the idle was really high. As I was learning how to bring the idle back down to specs, one of things I did was rotate the distributor a little either way. Between messing with that, adjusting the TPS, and adjusting the air/idle screw, the idle is now where it should be.

The noise that the engine makes I would guess or assume is valve noise, but I am not sure. It doesn't sound that much different to an exhaust leak - it's a really fast tapping sound. I can tell you the following about it:

-The speed of the noise corresponds to the engine speed.
-The noise is most common when the engine is warm and is at low to moderate RPMs.
-When I was rotating the distributor a little when I was working on the idle, if I rotated it so the RPMs decreased, the noise got worse; if I rotated it so the RPMs increased, the noise was not quite as bad.

Thanks for taking the time to read this and thanks for your input. I'd like to take a stab at fixing this myself, but I'd like to get some ideas first as to what the core issue might be.

 

It sounds like it could be your rocker arms or valve but it could be piston slap also your best bet would be to got to an auto parts house and buy an engine stethoscope they are like 20 bucks but well worth. Buying this will help you to find the area were it is. If its in the head its going to be your rockers or valves but if its coming from you cylinder your more than likely getting some piston slap

 

Thanks, that's a good idea. It's definitely more of a tapping than a knocking, so I suppose that would probably be something up in the valves or rockers, eh? I have heard that valves get loose after a while and need readjusted, maybe that's something to consider. I like your idea about the stethoscope though.

 

Well, first off, we need to know what motor we're talking about. I'll assume the 4 cylinder since you said "the" head. They all have noisy valve trains. The only way to really get rid of the tapping noise is to adjust the valves way tighter than spec, which is no bueno. I've done some experimenting and they finally got quiet about .003 on the intake and .005 exhaust. That's about half what factory spec is, but they were silent as the grave. I only did it to confirm it was the valves then went back to factory spec, which is .008 and .012. I'd check your valves, make sure they're to spec, and call it good.

 

Sorry, I meant to include that's is a 22RE.

Thanks for your advice - appreciated.

 

I did adjust the valve train last weekend. Nothing seemed too out of whack, but it may have helped a little.

After that I checked the timing. It was off. It was at -1* instead of -5* (with the jumper connected). I put it back where it should be, which made the idle too slow so I loosened the idle/air screw a little to bring the idle back up.

Overall the truck runs smoother now, so that's a good thing. It's not perfect.....but maybe it's just too worn to be so.

 

By rotating your distributor you were changing your timing. Probably causing the engine to ping. I bet now that it's back to spec, most of the noise has gone away? That and adjusting the valve lash.

 

It is better than it was, yes -- especially at lower RPMs. It still makes a sound at moderate to higher RPMs. I'm beginning to wonder if it's something else that corresponds to engine speed, like a pulley, water pump, etc. Maybe I'll try to take a video in order to record the sound.

 

After coming home from the store this morning, I took a couple videos so you can hear the noise I'm trying to diagnose and fix. I also hooked up a timing light to show the engine RPM. Since I had just been driving the truck, the engine was all warmed up.

In the first video, the noise can first be heard when the engine is at 1700 - 1900 RPM (about :05 seconds into the video). When the engine drops backs down to idle, the noise is gone. Here is the link to the first video:
I shut the truck off for a couple minutes, then started it up again for the second video. Now the noise can be heard right at the start of the video, when the engine is around 800 - 900 RPM, then around 1400 - 1500 RPM, and then around 1800 RPM. When it returns to 800 - 900 RPM (around :32 seconds into the video), the noise is gone. The noise starts again around 1800 RPM (at about :41 seconds) and continues until the RPM drops back down to idle, then it's gone again. Here's the link to the second video:
Thanks for giving it a listen.