tapping noise coming from front of engine.Chain slapping?random tapping.

[sm1nts2escape]

I just bought another 240sx 93 ka24de dohc and finnally got it running.I have ran it for about 2 hours total now.122,000 mile on the engine.Anyways there is a tapping sound comming from the front of the engine right near the oil plug but it does not sound like the ussual chain noise.Witch to me sounds like a loose bycycle chain.This tapping noise is inconsistent though.It has the same sound as a tapping valve but like I said it is inconsistent.All of the valve tapping engines I have heard in the past had a consistent tap loud or quiet.The tapping is mainly in the low rpms around 1 grand but still makes the noise in the higher rpms.It mainly taps the loudest when the revs are falling.I am thinking about checking the valve lash but it would be alot easier to check the timing chain.All help is appreciated.Thanks

[miked808]

Currently dealing with the same problem. Turns out part of upper Timing Chain Cover broke off and fell into the bottom of the Block and was getting rubbed by Timing Chain.

[TooManyMiles240,000!]

i have (what appears to be) the same problem on my truck which is a 91 ka24e...it runs fine anyways...but a solution would (hopefully) give some piece of mind, but don't be too worried i've been beating the he** out of it for over a year with the noise and no problems yet....

[OM3GA]

There is also a thing called a timing chain guide that is known to break and cause this noise.

[s14 2510's]

Take off the valve cover and remove the upper timing chain guide its not needed as long as you run oem timing chain kits. I think the upper guide was recaled somewere in the s14's for noise of the chain rubbing on the guide. I have seen some people on here that have had the chain cut the guide right in half. It could be that your tenshioner is going bad. It is oil pressure operated. I would replace the tenshioner (I think there cheap) and remove that guide then re rtv your valve cover and you should be set.

[s14 2510's]

Take off the valve cover and remove the upper timing chain guide its not needed as long as you run oem timing chain kits. I think the upper guide was recaled somewere in the s14's for noise of the chain rubbing on the guide. I have seen some people on here that have had the chain cut the guide right in half. It could be that your tenshioner is going bad. It is oil pressure operated. I would replace the tenshioner (I think there cheap) and remove that guide then re rtv your valve cover and you should be set. Do a compreshion test of all 4 cylinders that should tell you if you have a bent valve.

[Bigvinnie]

I just bought another 240sx 93 ka24de dohc and finnally got it running.I have ran it for about 2 hours total now.122,000 mile on the engine.Anyways there is a tapping sound comming from the front of the engine right near the oil plug but it does not sound like the ussual chain noise.Witch to me sounds like a loose bycycle chain.This tapping noise is inconsistent though.It has the same sound as a tapping valve but like I said it is inconsistent.All of the valve tapping engines I have heard in the past had a consistent tap loud or quiet.The tapping is mainly in the low rpms around 1 grand but still makes the noise in the higher rpms.It mainly taps the loudest when the revs are falling.I am thinking about checking the valve lash but it would be alot easier to check the timing chain.All help is appreciated.Thanks

The tapping noise comes from the upper and lower timing chain guides.I myself have just removed the upper guide hoping that it would remove the tapping noise since it is so irretating to listen to at red lights. The upper guide isn't really needed, so I just removed it, it had major wear and tear on it whan I removed it. Engine still makes the tapping noise which means the lower guides need to go as well. Total to remove the upper guide is in under 1 hour. To remove the lower guides add another 4 hours to that, and some new guides. To take your time and do it right is what it will take to open it up and fix the situation. Make shure that you have all new gaskets ready to go unless you plan to wait for some gasket maker to set up.