I just listened to the soundfile too, and at the end when you wound up the motor hard, it seemed to do it when you get on the gas hard and let go. I think it is internal, like a wrist pin knock or piston slap (GM is known for this). Does it get quieter as the engine warms up? A mild piston slap will go away as the piston warms up and expands to take up the slack. Another thing, I once had a 3.0 with a noise like that after the heads were "rebuilt" by a barnyard mechanic. It got worse until a cylinder lost power. Tore the engine down myself and found a burnt spark plug and burned valves. The idiot reground/replaced the valves, but never checked the valve guides for wear! The sloppy valves burned out in only 2,000 miles! So listen when you crank it over for "fast spots" when the engine cranks; that's a clue of a weak cylinder. I hope it's nothing major. Just let it warm up and take it easy, and adjust/reshim your valves every 60,000 miles (no, it's NOT free, you change/replace different thickness shims to adjust clearance, and they're $7 each). Good luck!

 

uggg I still have about 10 shims from my reshim job...grr

 

actually the sound gets louder as the truck warms up... I can't figure it out... we changed the rod bearings but not the mains... im leaning towards the "Exhaust reed valve thingy..." lol.. excuse my ignorance, but where exactly is that located???

Thanks!!!
Steven...

 

Got that classic sewing machine hum. well yours sounds like a broken sewing machine. Mine has the click noise as well i was thinking maybe valves.

 

If you look at the passenger side exhaust manifold you will see two tubes that bolt up to it. The one closer to the firewall feeds the Reed valve thingy. The forward one feeds the EGR system.

 

umm.... I'm almost positive that the sound is coming from the driver's side head... got out there with the stethoscope, and it seems like it's loudest on the drivers side head on the first cylinder toward the front... I'm debating about tearing the motor apart again, and taking the heads to a shop to get rebuilt... if I do, I will probabaly put some better cams in it too... I saw D.O.A. racing cams, but I have heard bad things about D.O.A. ... are there any other companies for the "More Power" cams??? and throttle bodies too... lol.. if i'm gonna tear it back apart, i'm going all out... lol...

Thanks!!!
Steven...

 

Well that reed valve has a hose that plums back into the intake box btwn the filter and the VAFM. So make sure those hoses are all intact.

Check out the alternator while you are at it as well as all the bolting hardware for the alt.

http://www.sea2skytuning.com/shop/ has the cams, very good dyno results from them and that's the route im going! Weasy2k is our contact here so just PM him!

 

any other ideas of what it could be??? I guess I'm hoping for a simple fix... probabaly not possible... but hoping so anyways... lol...

Thanks!!!
Steven...

 

Did you ever disconnect the alternator to see if that was it?

 

yep.... it's not the alternator, although it does make an odd sound... it's not the tapping... I can hear it Loudly on the cylinder head it's self, but not in the valvecover with the stethoscope... weird... I also can hear it in the exhaust too.... I'm just debating on driving the living poop out of it untill it finally blows up... then I will figure out what it is... lol...

Thanks!!!
Steven....

 

Sounds like a valve then. Unless you dropped a nut/bolt down the intake at some point.... :-)

The reason you can't hear it on the valve cover is because sound doesn't transmit that well through the gasket.

Good Luck!

 

yikes valve issues...

Heres a thought, could it be one of the ditributor drive teeth on the distributor or the cam? Pullyour distributor and have a looksie

 

ok... here's a new idea... I'm kinda missing the power and sound of my 1990 ford mustang 5.0 I sold before I got the 4runner... so what would happen if I threw in a 300ish horse-power ford 5.0 in the truck... good size cam, decent heads, and fuel injection... too hard??? Ive seen it done a few times... and I do think it would be worth it... my only problems with the swap, is how does the tranny hook up, and how about the motor mounts???

Thanks for any help on this!!!
Steven...

P.S.
I know i'm crazy... lol... just clarifying...