Tapping noise from 2250-2750 RPM's?

[qkslvr221]

What could this be? I've had this same tapping sound for 10,000 miles (since I bought the car over a year and a half ago). It only does it at these RPM's in any gear.

Someone said to me that there might be a little play somewhere in the engine, and that it's nothing to worry about, but I would like to figure this out. :beer:

 

[msm808]

is it coming from the under the passenger dash?

 

[qkslvr221]

Sounds to me like it's coming from the center of the engine. I will have a look tomorrow and try to pinpoint it.

 

[Ghost]

Spun rod bearing would be my guess, but I hope it's not.

 

[Doug]

a spun rod bearing isn't going to make noise for just 300 rpms. you'll get noise all through the rpm range.

can you be more specific with describing the sound? does it do it while sitting and free revving? does it do it in all gears? does it quiet down in 4th gear?

when was the last time you changed the oil? have you checked the oil?

get a friend to rev the car and stand behind the car and listen carefully to the sound coming out the exhaust. anything abnormal about that?

 

[qkslvr221]

a spun rod bearing isn't going to make noise for just 300 rpms. you'll get noise all through the rpm range.

can you be more specific with describing the sound? does it do it while sitting and free revving? does it do it in all gears? does it quiet down in 4th gear?

when was the last time you changed the oil? have you checked the oil?

get a friend to rev the car and stand behind the car and listen carefully to the sound coming out the exhaust. anything abnormal about that?

Sounds like a metallic chattering (maybe 5 times per second), does it nearly any time the engine is at that RPM level. Standing still or in any gear, and the noise completely stops as soon as 2750 is reached. Oil is changed every 2500 miles with 7 quarts of Mobil1 5w30.

 

[Cookieman00x]

Id say its a lashing adjuster or cheap gas...

 

[Doug]

doubt its cheap gas. does it speed up as rpms increase? if not, that rules out spun bearing.

Sounds to me like something is loose.

 

[qkslvr221]

Gas has always been 93 octane only. No wal-mart crap either. I can't really tell if it speeds up, and if it does, it's not by much at all.

Anyone have a clip of a bad lashing adjuster? If I could hear one, I could tell pretty quickly if it sounded the same. Same goes for the spun rod bearing.

 

[Doug]

i would rule out a rod bearing, then. I'm thinking something rattled loose. like an exhaust hanger. or maybe even a motor mount. does the car shake pretty bad?

 

[qkslvr221]

i would rule out a rod bearing, then. I'm thinking something rattled loose. like an exhaust hanger. or maybe even a motor mount. does the car shake pretty bad?

Doesn't shake at all. H-pipe and catback have been replaced, and did not make any difference.

 

[qkslvr221]

I asked the guy what he meant before, and he said that there could be some play in the wrist pins causing the noise at a certain RPM. Would a problem with a timing chain or related cause this?

 

[bvysochin]

Does it do it at all before the 2250 rpms? Can you get a video clip?

 

[duane v]

a spun rod bearing isn't going to make noise for just 300 rpms. you'll get noise all through the rpm range.

that's not true.....When I spun a rod bearing on my second motor, it would knock from 3000-3500 rpm and wouldnt make a sound anywhere else in the rpm band.....I removed the oil pan and sure enough, metal shavings in the oil pick-up screen ....DA snake boy!!!!

 

[qkslvr221]

Does it do it at all before the 2250 rpms? Can you get a video clip?

This is the strangest part IMO, it never has made any noise at any other rpm range. I sure will get a video clip up as soon as possible, I want to know if my engine is a "ticking timebomb" or what! :read:

 

[qwik01cobra]

I just got done putting my new motor in.... I had the same thing from 2250-3200 RPM's it would tap. I ruled out rod knock at first. But then I put new lifters in and it was still there. I pulled the motor to find 5 spun rod bearings and piston to head contact...

 

[qkslvr221]

Holy shit man, how does the motor not grenade itself with all those? I've been watching some clips of spun rod bearings, and it sounds nothing like my issue. Much more of a knocking sound, where mine is like fingers tapping on an empty can.

 

[NinetySixSVT]

Can you try to pintpoint it more? Video clip possible?

 

[qkslvr221]

Well, I did some messing around today, and found some new details.

-Happens between 2000 and 2750 RPM depending on the incline (this surprised me, going uphill it did it at a much lower RPM, where free revving it did it at 2750)
-Only makes the sound for 100RPM each time, then completely stops
-Does it more with the AC on

Could it be something rattling from a drone when the throttle is open a certain amount?

 

[NinetySixSVT]

Well, I did some messing around today, and found some new details.

-Happens between 2000 and 2750 RPM depending on the incline (this surprised me, going uphill it did it at a much lower RPM, where free revving it did it at 2750)
-Only makes the sound for 100RPM each time, then completely stops
-Does it more with the AC on

Could it be something rattling from a drone when the throttle is open a certain amount?

just a random idea...have you played around with it based on how much the throttle is open?