Clicking Noise Heard Upon Throttle Stab

[KJL]

Hearing a little clicking noise when a mildly stab the throttle from idle. Got my stethoscope out but seem most noticeable if I removed the rod part and just listened in the general exhaust area. Couldn't pick up much when placing the rod against the IH's or head. I guues it could be an exhaust leak but it sounds to metallic for that. Engine runs fine. I did just complete some port work on the heads and it is possible a few small flecks of aluminum may have made it into the cylinder. Not that familiar with OHC engines and looking for some input regarding possible cause and additional diagnostic ideas.

I can also hear a little click when driving with the windows open at times.

Just dyno'd the engine to 7000 rpm and it achieved 400 rwhp. Clicking was there before testing however.

Thanks!

[Marc Haibeck]

It's likely that the dual mass flywheel is a little loose. It's just an annoying sound. It might get louder but does not lead to a catastrophic failure. You can address it when the next clutch service is due.

[KJL]

After further checking I am not sure if sound is coming from rear of engine. It is a light metallic tick that would be compatible to a noisy lifter. It only happens upon throttle stab at idle and also seems to happen while throttling under load. I wish there were a trained ear locally I could bring it to who knows these engines. I have also heard similar sounds form noisy cam chain followers on other OHC engines. Is there anything in the valve train that could be the cause if it isn't the fly wheel?

[LGAFF]

Mine has lifter noise also....brand new lifters too on the rebuild too....6K+ miles no issues. Comes and goes seems to be dependent on the weather....BMW had a lifter issue in their N52 engines....

Other possibilities: exhaust leak, chain tensioner(unlikely), Serp belt tensioner...

[KJL]

Thanks for the input. Just annoying and I don't want to ignore anything that may get worse.

[LGAFF]

this sound?

https://www.youtube.com/watch?v=EhLP-RkFGXM

[KJL]

It is similar but not as loud are "heavy". It is more of a light metallic "chirp". I plan on looking into it further but first I need to get it home, it is sitting at a restaurant parking lot with a dead alternator. I knew I had a intermittent issue with the regulator. It would also just stop charging then start back up again. I guess I will rebuild it with ECHLIN parts from NAPA. Need to first see what unit it is 124 or 140 amp. Sounds like the remains don't last long.

[LGAFF]

Are you sure it wasn't just the alternator and sound echoing.....

[Marc Haibeck]

Does the sound have any resemblance to the so called "chain rattle" clicking sound that is sometimes heard at start-up? If so it could be a loose secondary chain tensioner. It should be easy to isolate a tensioner sound to the left or right cylinder bank.

[KJL]

I recorded the noise with my phone while holding it down near the driver side exhaust manifold while I stab the throttle. I captures pretty much what I am hearing. It is definitely coming from this area of the engine.