4age making a tapping noise

[Moebius]

Happened when I started it up for the first time in a few weeks. Was running fine previously. It's a bigport 4age in an ae71.

I don't really know how to describe the noise other than a tapping sound. It doesn't sound to me like an injector ticking noise or an exhaust leak. I've tried listening to various parts of the engine with a rubber hose up against my ear and I can't pinpoint where it's coming from. The noise goes away when I rev the engine, but comes back immediately once it drops back to idle. I've only run it for a few minutes but it didn't seem to go away after warming up.

I've taken the rocker covers off and there is nothing that jumps out at me as being wrong. I checked all the valve clearances and they are all within spec, except one of the exhaust ones which is 0.03mm extra. The oil was changed only a few hundred kms ago, and still looks fresh both on the dipstick and in the head.

This is the best video I managed to get where you can hear the noise - https://youtu.be/xT7P22dCTiQ

Any ideas or suggestions?

[Ben Wilson]

Try pulling the leads one by one, see if it's isolated to a single cylinder.

[trdee]

Do you have an oil pressure gauge?

[allencr]

Listen with the oil filler cap removed?
Size & length of hose? A meter of vacuum/windshield washer hose is NFG, 1/2 meter of 12-16mm is much better, so is material that isn't soft & will absorb some of the sound.

[webby]

Check all you bolts on your accessories. I have an SR20 once that had the same issue thought it was the timing chain tensioner (common fault) turned it it was a loose bolt on the alternator bracket same symptoms only at idle...

[Moebius]

I've been trying to get a hold of an oil pressure gauge, no luck so far. I'll try everything else suggested, thanks guys!