Mystery Sound from KA24DE

[spg240sx]

Ok guys, I need some detective help from you. I have a 96 KA24DE and I am getting a repeating tapping noise from the rear part of the head between 2000 and 2800 RPMS. I know it is not the timing chain because I have heard that sound before, not to mention it is coming from the rear of the engine. I also don't think it is a rod knock for the following reason, I can remove the plug wire from cylinder 4 and the sound will stop. Any suggestions on what this might be? I'm going to pull the valve cover and head off in a few days to find out for sure, but I want to see if anyone thinks they may know the culprit. Thanks

[spg240sx]

Anybody have any ideas?

[ericcastro]

maybe a valve tapping. they are hydrolic valves and cant be adjusted iirc.

is your oil level ok?? have you changed oil wieghts lately?? have you changed oil lately?

[nastynate805]

I have a similar problem when i rev it past about 3k it makes like a funny noise like something is loose i havnt had a chance to track it down yet as it has been raining like crazy on the Central Coast (cali). I have changed my oil but i'll be checkin it out this weekend i'll post what i find.

[LA_phantom_240]

I would lean toward either an injector, or some sort of heat shield.

[180sx_Drifter]

check and see if anything is loose in the back. I started hearing a metal tapping noise and it ended up being one of the mounts for a turbo coolant line that i didnt bolt down.

[RR240SX]

Sounds like rod knock. If you pull the plug and eliminate the explosion in the cylinder and the noise goes away then that is the symptom of a rod knock. If it continued to knock or tap it may be something else.

[joshchewuhh]

I have a similar problem but i have a sohc. Im pretty sure its not the timing chain due to the fact that its in the back of the engine and i only have 110xxx miles on it. I also have taken off my head and checked the tension on the chain but there was no play.
I think it might be my heat shied. I am not too sure

[joshchewuhh]

okay i just took off my heat shield and its gone
soo take off your heat shield on your header

[lflkajfj12123]

that could be a slight knock starting i'd be careful

[nastynate805]

yep i have the same problem i hear a weird noise about 3100rpm traced it down the other day to a heatshield. so i'll live with it its not hurting anything.

[spg240sx]

Pulled the valve cover, everything looks normal so far and appears to be in spec. Guess I'll pull the head tomorrow and do some more detective work.