The unfindable tapping noise

[dogfishguzzler]

Ive already done some open complaining about this so some of you knew this was coming but heres what I got.

I have a tapping/clicking noise but not at idle or higher rpms, its like low to mid range. I dont have a tach so I cant give any specifics about the range. I have a saginaw four speed (not sure about the rear end) but when Im going around 40-45; Im guessing around 1800-2200 rpms the ticking is very distinct but its not constant, its more like its on a wave or a harmonic if that makes any sense kind of in and out in a very smooth pattern or wave. I bought a stethescope and found one loose rocker which helped but today I started my truck beside a wall and I could hear it very good once I gave it a little gas. Im axious to fix this since it worries me. If Im just being paranoid that would be great but I think somethings up lol. Any insight on things to check would be killer. Thanks guys!

[chucks70]

Have you messed around with the flywheel lately? Out of balance? Broken or cracked tooth ring? I'm just throwing out a couple of ideas. How about the harmonic balancer rubber going bad?

[dogfishguzzler]

Is there an easier way than taking the starter off and rotating with a breaker bar to check the teeth on the flywheel? And I have no idea how I would check the harmonic balancer besides to take it off and test it the way the old prospectors did for gold and even then I have no idea if there should or should not be an indention left when I bite it lol.

[dave2953]

When I checked mine the last time I put a wrench on the flywheel to torque converter bolts to rotate the entire assembly. You'll also want to check for cracks around the flywheel to crankshaft bolts or on the surface of the flywheel itself. My truck has a noise like you describe coming from the fuel pump. That's another place you may want to check.

[chucks70]

As far as the flywheel, remove the flywheel cover and put a breaker bar on the bolt that goes through the balancer and turn away. Usually broken teeth you can hear with the starter, cracks and such are harder to spot. As far as the balancer, the only time I saw one bad it was actually missing chunks.

[dogfishguzzler]

The fuel pump was my first AHAH!! I found it place but I abonded it thinking there is no way it could be that loud but I guess the flow of gas could in theory cause the noise the go in and out in waves. Is there a fix or is replacement my only option?

[dave2953]

Sometimes the spring for the pump arm gets weak and can cause a noise (or so I've been told) but in my case I put a brand new pump on and the noise persists. I don't think there's a fix outside of replacement and the pumps are relatively cheap anyway. I could always hear my noise through the pass. side motor mount with a stethoscope when I realized it was the fuel pump.

[dogfishguzzler]

Well it cant hurt to replace it then. Ive been all over the engine with a steth and the only two spots where clicking was more pronouced was at the rear of the drivers side head and the fuel pump, but keep in mind when I say "more pronounced" I could still only barely hear any ticking at all. its mostly when I pull beside a wall or something that its really loud and only then when I accelerate away. Keep the ideas coming guys Im making a list

[71 super]

Small or bbc? I have A 402 with a tick at idle but goes away with rpms. I too have been all over with a steth. but to no avail. The fuel pump was replaced because it was the loudest there, Rockers have been adjusted, replaced and a different set of new valve springs and three sets of lifters changed- even went as far as pulling the rear freeze plug at the cam in case it was in too deep, still a tick- You might check for wrist pin and also use a timing light to determine if it is in time with crank 1:1 or in time with valve train 2:1 (taps to rotations) this should give you a starting point- by the way my BB was a fresh rebuild- don't know if this was a vent or help??? Let us know what you find.

[Boog]

Exhaust manifold gasket leaking when under acceleration. Probably from the rear port on driverside.

[Bus Ted Knuckle]

I would check for an exhaust leak. They will sound like a tick.

[Longhorn Man]

these last two was where I was gonna tell you to look... check out for an exhaust leak.

[Cobraguy]

Possible preignition (ping) check the timing. Also check to make sure the centrifugal weights are not stuck in the distributor.

[84_4x4]

could be spark knock might want to retard timing (i think) or run higher octane

[special-K]

Did you put the steth on the timing cover?Easy enough.Usually a worn chain will tick when letting off or at idle,though.

[dogfishguzzler]

When I bought the truck I was told it needed a doughnut gasket but when I pulled the exhaust off the headers I didnt see anyway a doughnut gasket could go there, maybe (very likely) I dont know whats its supposed to look like. maybe Ill take it back off and snap some pics and you guys tell me if it looks like it should. Also I will check the header gasket again. I already switched to premium gas and that didnt help but I havent messed with the timing yet. I like the timing light idea thats slick Ill pick up a light this weekend. Have to goto work now so Ill check this stuff this afternoon and get back with yall. Thanks!

[special-K]

There is no donut gasket with headers.Just the gasket at the head and the collector.The donut gasket would be betwwen the outlet on the exhaust manifold and the head-pipe (exhaust pipe).

[piecesparts]

Iwould definitely try the fuelpump change out. I had one that sounded like a bad rod, once.

[dogfishguzzler]

Oh what a day! Anybody here ever been to charlotte NC ? Ever drove down 74 ie Independance blvd? ever drove down independance with your 4000 pound truck stuck in 4th gear? this day has been such a bastard I havent had a chance to try any of your suggestions yet. I did stop by the parts store and buy a fuel pump but since I have no grease itll have to wait till tommorow. The linkage on my Vgate is sticking and I cant figure out why but I have the boot removed and I know what to snatch when it hangs so atleast I wont be doing rush hour in charlotte in four gear alone ever again(cant believe I still have a clutch plate!) To add to todays snafu itenerary my step daughter had to goto urgent care (she is fine btw) but my truck wouldnt start when it was time to pick her up; thank god for the rouge air freshener that I found I was able to use the string to tie up the sticky choke and pick her up lol so I picked up a choke cable as well. Until my plate clears up in the next day or so Ill have to wait on the tick as much as that bugs me. But I havent forgot about your suggestions and Ill be back in touch as soon as possible, thanks again.

[hgs_notes]

Exhaust leak. If you notice it get louder or more distinct when goind through a drive through, or passing cars, or near a wall, etc. Just try checking the exhaust manifold bolts for tightness to start with.

HG

[dave2953]

And I thought I had a crappy day.

[corn]

header gasket would be my guess. sounds a lot like a lifter ticking. put a set of exhaust manifold gaskets on it & be done with it. good luck...

[dogfishguzzler]

holy crap! I dont have an extenstion long enough to get to most of the header bolts but I found two diffrent size bolts (3/8 and 1/2) is that normal? also I dont have a torque wrench I will be going to get the extenstion and the torque wrench tommorow but anyway with a little tiny 6 inch long wrench I was able to turn all the bolts I could get to atleast a quarter turn with no sweat now I know that aint normal is it? I bet a million dollars tommorow after I get my stuff I find all of those bolts to be way looser than they should be I think I may be on to something here lol. This is exactly what I meant by you guys needing to help me because Im ignorant when it comes to engine work. Ive been doing tool and die for 13 years I can make anything and make it right but when it comes to wrenchin Im lost but I think my edumication has begun!

[dogfishguzzler]

quick footnote I was reading this
http://www.chevyhiperformance.com/te...haust_gaskets/

All I can say is damn

[dave2953]

If they are that loose you may have burned up the gaskets. It probably wouldn't hurt to replace them if you can.

I was too slow.