Making a bad tapping sound?

Post by **mulletmrt** » Wed Nov 20, 2002 8:56 am

Hi guys I got a question. Just a few days ago my 89 s13 began making a tapping sound that appears to be coming from under the valve cover. I asked a few people and looked on here to see if this was common. A few people told me it might be a lifter or the timing chain. Also I don't know if this helps but before it started "tapping" I changed the spark plugs and the #1 spark plug was very carbonized. Would this be a product of a loose lifter? Also someone told me that the lifter could be adjusted. Is this true? If so then how could I do it?(because of lack of funds at the moment started my own business doing graphic design) I'd really appreiciate the info Thanks Mike:)

Post by **crypt2k** » Wed Nov 20, 2002 8:56 am

it can be your lifters or your car might be in need of an oil change... first off check the oil and change it if its too grimy...

let it run for about 30 minutes and see if the sound come off. if it doesnt then its one of your lifters that needs adjusting.

i just went through this last week so... this is good advice.

Post by **bruinbear714** » Wed Nov 20, 2002 8:56 am

your timing guide probably broke and ended up in your oil pan. The tapping you hear is the timing chain rattle at idle...

Does the sound go away when you rev the engine at 2k? If so, its definitely the guide that broke off. If the sound is still there, then you might have a couple bad rockers.

If I were you, I would get that timing guide OUT of the oil pan ASAP since it will melt in the hot oil and end up in your valvetrain, where it will cool down, harden, and clog up the hair-thin oil passages

Post by **mulletmrt** » Wed Nov 20, 2002 8:56 am

I honestly don't think its a timing chain guide, because it still taps at all RPMs. The weird thing was that this morning it did it , but the rest of the day it hasn't done it. The oil did look a little dirty, but I had it changed less than 1000 miles ago. I'll check again to make sure though. Would there be an explaination for i doing it every so often?

Post by **mulletmrt** » Wed Nov 20, 2002 8:56 am

How would I be able to adjust my lifters though? Would I hve to torque my valve cover back down? If so what spec?

Post by **bruinbear714** » Wed Nov 20, 2002 8:56 am

Well if its not the timing chain then its your rockers. And the reason for it only tapping in the morning is because it loses the oil pressure in its hydraulics from sitting overnight.

Pull off your valve cover and give each rocker a slight tug to see which one's are tapping. Then turn your crank 180 and give them a feel again. Turn crank another 180 and give them another feel.

They should all feel tight and have no freeplay. If your oil is a little dirty, I would try dumping in a quart of atf fluid and run your car moderately hard for a few miles to clean up the gunk in the rockers. See if that helps. Then change out the oil.

Post by **mulletmrt** » Wed Nov 20, 2002 8:56 am

Thanks Would I have to torque the valve cover back down? If so what spec? What about the rocker? Would that have to be torque to a specific ratio?

Post by **bruinbear714** » Wed Nov 20, 2002 8:56 am

I don't remember the torque specs off the top of my head for the rocker arm bolts, but here's what I did for the valve cover:

I just used the small 1/4 ratchet to tighten the bolts, but tightened them very loosely. THere's already a gasket in between the cover and the head, so no need to clamp it down that tight.

As for the rocker arm bolts, I would just tighten them down moderately for testing/fixing purposes and then torque it down later when your done fixing the car.

Post by **Justice** » Wed Nov 20, 2002 8:56 am

ok, i just bought a 95 240sx se and she is having the same problem. nock nock nock. sounds like tis comming from right under the valve cover. going to take her apart today i think.

Post by **Two-Forty** » Wed Nov 20, 2002 8:56 am

I have a 92 and it's slightly tapping at idle, sounds like its coming from the valves too, so how do I tell if it's the timing chain or the rocker or lifter...

Post by **96_S14_SE** » Wed Nov 20, 2002 8:56 am

For the last two you sure your not paranoid about the injector pulsing? My car makes clicks or taps or whatever you want to call it for as long as I can remember. Before that my 91 did the same thing. My car is 100% sound, and most of the tapping clicking whatever is from the injector pulse, ei: opening and closing.

Then there is the common noise the KA makes at idle due to reciprocating cams and lifters / shims, and valves opening and closing.

Post by **bruinbear714** » Wed Nov 20, 2002 8:56 am

yeah remember that the injector clicking is a lot more higher in pitch than the timing chain rattle or the rockers knocking

Post by **96_S14_SE** » Wed Nov 20, 2002 8:56 am

What chu talkin about willis? I dont have any rocker arms hehe.

Post by **joe_keyzer** » Wed Nov 20, 2002 8:56 am

My car was doing the weird taping sounds and one day after looking hard I found that 4 of my exhaust manifold bolts had rattled out.

Went to the hardware store with one of the bolts that was still left got new ones and bammm no more noise. it's worth checking just pull off the heat sheild and look.

-Joe

Making a bad tapping sound?

Making a bad tapping sound?

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