Help.. annoying noise

lonewolf_2626 · May 13, 2006

ok.. 97 Gmc 1/2 ton 4x4... New rebuilt motor.. vortec.. comp cams .380/.388 lift.. aluminum angle plug heads.. 160/202 valves.. headers.. converted to electric fan

put the motor on got about 1500 2000 miles on it now.. starting making a pretty good tapping noise.. dont matter if its cold or hot.. thinking maybe lifter.. but doing the ol screwdriver to ear and searching it dont pull any noise up from the intake area at all.. but put the screwdriver to the headers and you can hear it clear as day.. noise increases with RPM's... changed oil.. pulled valve covers off no loose rockers or anything.. pulled distrubitor out gear looks fine.. no major gouges on it or anything.. it is not a knock it is defitentaly a tapping noise.. not increasing in volume over the past 2 weeks or so.. staying the same.. loud enough to hear it over the HO converters and morosos spiral mufflers.. (very loud exhaust)

Anyone have any ideas? Am I looking at possibly bad lifters? lifters were new along with motor.. new pushrods.. only thing i didnt get new is rockers.. could that be causing the ticking? oh and oil pressure is great.. no problems with oil pressure at all.

Please any sugestions would be greatly appreciated.. dont want to replace lifters (too d**n expensive and too much work)

Nice rig · May 13, 2006

I know for a fact that a slight exhaust leak either from the manifold gasket or a crack in a weld of your down pipe will cause a tick/tap noise. Had a tick/tap in my truck once before. But one day when I got on it hard from a stop, the whole weld from where my header and pipe mated up gave way. Got the weld fixed and the tick/tap never came back...of course when the weld gave way it was more like roar then a tick/tap. Take a paper towel and run it around the area you think it might be coming from, you will be able to see it blow the paper towel if it is an exhaust leak. Of course start off with a cold motor...gives you more time before it heats up.

lonewolf_2626 · May 13, 2006

No exhaust leaks.. checked that out.. its defitently a tapping noise.. just like metal on metal.. increases with RPM's, then when changes gears it quiet's down, but as you increase RPM's again.. it gets louder.. you can really hear the noise when you take the ol screwdriver against any of the header pipes, or in the back of the engine on the intake by the distributor.. its not a clanky clank.. or a rod nock at all.. defitently a tapping..

totally confused at to what it could be

Halen5150 · May 16, 2006

Did you figure out what the noise is?

lonewolf_2626 · May 16, 2006

As of right now.. no I havnt figured it out yet.. too the point unless someone can give me another idea.. of tearing the intake off and just replacing the lifters..

Halen5150 · May 17, 2006

I have a similar noise, but I have yet to figure out what it is. I was thinking it was a lifter, but I'm not sure. It's definitely not an exhaust leak. Please let us know if you figure out what it is. Good luck!