Tap Tap Tap!!! What is that noise?

[blurple124]

Hi friends!

I've got a distinct tapping noise coming from my engine and I need some help diagnosing it.

Here's what I know about the car right now:

1. It sounds like this (recorded yesterday): https://drive.google.com/file/d/0B9HKzg ... sp=sharing
2. The sound is coming from the forward part of the engine (sounds like it is coming right from Cylinder 1).
3. The sound does not go away when removing plug wire #1
4. All valve clearances are good:
Cylinder Intake Exhaust
1 0.017 0.018
2 0.018 0.018
3 0.017 0.02
4 0.018 0.02

5. Water pump is leaking (unrelated?)
6. Engine fan is not switching on (fan works fine, this seems to be temp sensor)


Are these two separate problems?

[So Cal Mark]

I'd check the cam gear. If it's a plastic gear it may have a loose center hub

[blurple124]

Hmm. Is that a "tighten to fix", or a "replace to fix"?

[bradartigue]

Hmm. Is that a "tighten to fix", or a "replace to fix"?

Most likely replace.

Also inspect the water pump pulley. I had one tapping along (I didn't know what it was) and it shattered, leaving me on the side of the very hot interstate on a summer day!

[Odoyle]

As Brad said, I would check your cam gears for any kind of play. Next would be to look at the leaking water pump and examine the concentricity of the pulley when the car is running, (I.E. look to see if the water pump pulley is wobbling when the engine is on).

[707kevin]

Sounds EXACTLY like my worn plastic intake came gear did.
Try isolating the sound with a dowel or large screwdriver and I bet you'll hear it right behind the cam gear on the tower louder than anywhere else.

[garion]

What years did they use those plastic cam wheels? I have a similar noise... I *think* its coming from the rear of the engine, but I haven't investigated that deeply yet. I plan on checking my valve clearances this weekend.

[garion]

Welp... I just measured one of my valve clearances, intake on #4 (happen to be in position when i removed the cover).. Its somewhere between 0.16 and 0.11, as I dont have the inbetween ones in my set.. Definitely too tight.. And the #2 exhaust is also in that same range, wayyyy to tight. Time to get a new set of feeler gauges..

[azruss]

John, normally tight gaps make less noise, not more noise.

[707kevin]

Mine was 75 with plastic intake, steel exhaust pulley.

[garion]

Russ: I figured... But I only measure those two I listed. I have not measured anything else. They happen to be in position when I pulled the covers off.. Once I realized that I don't have a full set of feelers, I stopped.. Not to mentioned, my feelers are old as hell..They dont look rusted, but....

I should have new feelers tomorrow, and will do all the measurements this weekend.

[azruss]

I should have new feelers tomorrow, and will do all the measurements this weekend.

I have feelers, mics, caliper, shims and tools. PM me and let me know if you want some help on Saturday. I'll talk with wifey tonight and see what going on. I think she is tied up so that gives me some "free" time.

[profcucchi]

You guys are fantastic! Like an old school mechanic you know the issue from the sound!

[garion]

Russ: PMed you.

[707kevin]

Have you eliminated the possibility of a plastic intake pulley yet?
Do you have a plastic intake pulley?