Noise in motor..Please help

lonewolf_2626 · May 14, 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)

mmmikkke · May 14, 2006

Ok...I read your thread in Performance Engines, similar question. One forum member suggested it could be an exhaust leak. I would have suggested the same, given what you have said. But you replied to him that you *know* it's not an exhaust leak...What makes you say that. It has the perfect signature for it...gradually started happening after the first week or two, now is stable at a certain loudness.

But ok, maybe you have ruled that out.

Next question: What did you do about the EGR in the intake manifold? Maybe it needs some attention.

lonewolf_2626 · May 14, 2006

Its not an exhaust leak because I did what he had suggested.. I also took both of the headers away from the heads, and did some exploring in the ports to see if there was something there.. seeing how you can hear the noise with a screwdriver on the headers.. I replaced the headers and then used the paper towel trick to look for exhaust leak.. all around the headers.. from the flange to all the welds.

The EGR fitting was welded into the new header so as to be able to use the EGR system.. It was taken off the stock manifold, and holed drilled into new header and then fitting was welded onto the new header.. so the EGR system is intact and working.

Another question I have.. I was told by the performance shop where I purchased the headers not to use header wrap.. as it will trap water and rust out the headers. how true is that? If that is true.. is there anything else to use that will help block the extra heat the headers put out?

100R1 · May 14, 2006

Header wrap will increase moisture and cause accelerated rust.

Are your headers steel, coated steel or stainless steel ?

Header wrap reduces the heat in the engine compartment, other than that there is very little performance gain.

Ceramic coating is the way to go. If yoiu want to wrap your header purchase Silica Tape from a industrial insulation supplier. Silica is good for 2,300° F.. the standard Header wrap is fiberglass and only good for 1,000° F.. Fiberglass header wrap is made from recycled glass bottles. If you have ever wraped headers before you know how it melts and turns solid and brittle.

As far as the ticking noise, I would have guessed a out of adjustment clearance on a rocker / valve.

Blocked oil passage in a lifter?

Bent push rod?

I once Bought a Gremlin X with a 304 that had a stuck lifter that ticked so loud it almost sounded like a knock. Couple of oil changes with Marvels Mystery oil cured that lifter (stuck lifter will cause engine to idle rough). Talk about a ugly car that Could not keep shoes on the rear!