Hi everyone,

Got out of work today and started up the car. I immediately heard the worst noise I have heard come out of my car. There is a loud tapping noise, but I'm not sure from where. It speeds up when I rev the engine but does not seem to get louder. As soon as I let go of the accelerator after revving it, I hear a metal rattle. I drove home at a max speed of 50 mph while trying to keep the RPMs low. Once the engine warmed up, the sound disappeared, but I think I still hear something while idling with the engine warm. (I'm not sure, it may have been some other noise.)

Here is a video (excuse the muddled f-word in the vid, but you probably wont notice it):
http://www.youtube.com/watch?v=k1AP5iKkfFM

What is it? Valves, lifters, something else?

 

hey i have the same type of thing going on with my 87 5.7 tpi iroc it just started when cold and stops when it warms up i was thinking maybe a lifter needing ajustment i put some stuff in the oil to quite noisy lifters did not seem to work seems to be coming from the right side of engine there are some smog check valves on that side if i find out i will let you know if you find out let me know irockman

 

might be the valve lash needs adjustment.

 

Dont flame me, because i dont remember correctly, but when i was in wyotech i had a supra that would do the same thing and a big poof of smoke at startup first couple seconds. Anyway he told me i think, that the valves expand when hot, and my valve guides were worn. So this would let the valves rattle and let alittle oil in the cylinders when it sits and cools down letting some slip by. Like i said, im pretty sure this is correct.

 

The noise was not there this morning. This is weird. hopefully this does not happen again when I go back home from work today.

 

I think it may be valve lash adjustment as your first post said as the heads which are trick flow have about 40,000 miles on them and gaskets were replaced not to long ago as the antifreeze destroyed them the valve lash was adjusted a couple of times by a shop which means nothing i know lol but hey thanks for your reply and i will post when i find out what is going on IROCKMAN

 

Sounds like piston slap...it stops when the engine is warm because the rings are expanded all the way.

You check your oil for cooper flakes? how is your oil pressure?

http://www.youtube.com/watch?v=q8qb0ur4e8A

 

I had the same thing happen with mine there was no noise the other morning and i thought maybe the additive that i put in for lifter noise had fixed it but it was back the next day it seems worse when it it cold out on my car it only happens in the morning at first start up IROCKMAN

 

well maybe but the other day i started it up cold in the morning and there was no noise also the heads were off not very long ago and there was no ridge on the cylinder wall looked good about 130,000 miles on the lower end thanks for your post IROCKMAN

 

I thought piston slap only happened on the later TPI's, LT1 and especially the LS engines? There is another thread on here not to long ago that went through all these slaps, tinks, taps, dinks, knocks, pings etc. I didn't post or subscribe so I'll have to find it again, found it when looking at New Posts.

 

Piston slap can be caused from the rings being worn or cylinder out-of-round.

 

chas is an idiot!! lmao jk buddy

it sounds like your crank is tapping the oil pan, loosen the oil pan bolts and hit it with a rubber mallet, put your hands on the pan too, you should be able to feel it

im putting my money on that

 

Piston slap is from the piston skirts being too much smaller than the cylinder than they should be.

That doesn't sound like piston slap.

And certainly there's no reason for anything to suddenly start hitting the oil pan (unless a rod cap is coming loose).

Sounds more like an exhaust port leak from the video. If it isn't that, and since the sound is even (not KNOCK-knock-KNOCK-knock, etc.), it isn't a rod bearing (or anything associated with a rod/piston). Might be a rocker, but the way it varied as you walked around, I doubt it. Main bearing would be the next possibility, but I doubt it - doesn't sound "hard" enough.

Does it really go away when the engine is warm?

Had you been hot rodding it before it started making this noise?

 

It hasnt made the noise again. Just got back from work with no sign of the noise. When I got home from work yesterday, the noise had gone away (I couldnt hear it but maybe it wasnt as loud) so I assumed it went away when the engine warmed up.

If by hot rodding you mean driving hard in the past few weeks, then yes. I drive to work around 80-85mph since theres not much traffic in the morning. When I get out of work, theres a bit more traffic but sometimes I step on the gas and get the car to downshift to pass someone so the RPMs can reach 4-4.5K RPM but its not a constant abuse of the motor.

 

on cold starts for years I have a ticking/clanking type noise and its my air tube from my exhaust/converter.Something with the shield.When it warms up it goes away and it doesnt always do it.If I hold the rpm up at start it will go away.Just a thought.

 

Hmmm, listened to it again. Sounds like a single cylinder with an interval coincident with one cycle (in the 4 cycles). So, that could be an exhaust leak, or may have been something involving a lifter.

An exhaust leak isn't likely to heal itself, but a lifter could have gotten something in it that later flushed out.

Come to think of it, a couple of years ago I had a sound similar to that that would come and go. Turned out to be a broken valve spring.

 

screw it! put in a 350!

my friend put a built 383 in his 93 z28 when he was getting coolant in his oil... later found out it was just a bad intake manifold gasket lol

 

sticky lifter !!

80's 305....... those were great for the cam lobes going flat.

 

Hey i just found out my loud tapping noise was from a bad intake gasket even though it is not very old i am losing a little water not in the oil though and the car has been running funny due to the intake leaking vac leak so i hope this helps you i thought mine was a lifter as it sounded just like one IROCKMAN