engine noise

[DissFigured]

FYI: 289 Automatic, no AC

My engine is making a tapping noise. sounds similar to when I once had a couple loose header bolts. I have narrowed it doen to the passenger side, and seems to be coming from within the valve cover. If I gun it, it starts to die.

I had a guy listen to it and he said I should remove the valve cover and look for anything out of the ordinary. I have removeed the valve cover and I do not know what to look for. I am new at this.

Only thing I notice is that 6 out of the 8 rods under the rockers are able to be moved by bare hand. I can twist them between my thumb and fore finger. two of them, I am unable to move and some of them feel like they have some dried cooked on grit like a grill after cooking on it.

What should I do next?

 

[toolwench]

I may or may not be able to help, but I do have a few questions first...

When you "gun it" it starts to die... "it" meaning the engine or "it" meaning the noise goes away? (I didn't want to assume)

Is the sound there when you start it up? Does it fade as the engine warms up?

Once upon a time when I first got my car (289 back then), I'd start it up...it'd rattle and then go away after about a minute or so. And as it was revved, the rattle increased until it went away. A friend of mine listened to it and immediately said, "Stuck lifter." They're hydraulic and one of the ones on my #4 cylinder took awhile to fill with enough oil. I unintentionally fixed it when I replaced all the lifters, push rods and rocker arms as part of a head rebuild.

I dunno if that's what's going on with your engine, but it might be something similar.

 

[6FIVE_STANG]

NOT TRYIN TO STEAL THE THREAD BUT I HAVE THE SAME PROBLEM, THE NOISE STARTS WHEN I FIRST START THE CAR AND FADES AWAY WHEN WARMED UP. SEEMS TO BE COMING FROM THE DRIVERS SIDE VALVE COVER? ..WHAT CAN IT BE?

..sorry bout the CAPS!

 

[DissFigured]

It is definately worse when the car starts up. And by die, I mean the car, it starts to sputter and if I don't let off the gas, the car will stop running.

The noise does not go away. It continues while the engine is running and never fades away.

If it is a lifter, what do I do? Do I just take the rocker arm off, put in new rods, and put the rocker arms back? Is this one of those things where it has to be torqued to a specified amount of tension or can I just swap out the parts and tighten the arms back down ?

 

[toolwench]

6FIVE_STANG, sounds like you have what I described...a lifter or two that take awhile to fill up with oil. I honestly don't know if just replacing the lifters will cure this. It might also be an oiling problem. In my case, it wasn't an oiling problem and replacing the lifters, etc. solved it.

DissFigured, sounds like you've got a much bigger problem...which might be an oiling problem, too, but perhaps more serious because if oil's not getting into the lifters, it might not be getting into your cam bearings either. I once had an oiling problem which after about 200 miles into a 300 mile trip, spun my cam bearings and toasted my entire motor. Before the catastrophe hit, though, I lost considerable power and my gas mileage went to gallons per mile. The engine was pretty loose and had a lot of miles on it already.

If your engine isn't too high mileage, you might consider freshening the top end. Depending on how deep you want to go, lifters and push rods can be replaced without too much hassle, but you will definitely need a torque wrench and a set of new rocker nuts at the very least. Like I said, when I had this problem, I ended up fixing it by having the heads rebuilt and replacing the lifters and push rods at the same time just because it was all top-side and I could get to everything by taking off the intake manifold. Your problem may be much deeper though, since it dies when you gun it. But also, if the lifters aren't filling with oil, they're also not making good connection between the cam and pushrods, which will make the rockers not open the valves enough. If an engine can't breathe in and out, it will die.

 

[DissFigured]

May be a dumb question.

Can U run the engine with the valve cover off? If so, should I be able to see something wrong while it is running? Will the faulty lifter be acting different than the others?

 

[toolwench]

You can, but you'll get oil everywhere and not be able to see anything. I know there's a way of stopping the oil, but I've never done it, so I don't know how. My various valve troubles have all been painfully obvious by either the rattling sound or pulling off the valve cover and finding a rocker arm off a valve, a keeper just sittin' there and a bent pushrod oddly out to the side. Beyond those, I just don't know.

I'm surprised nobody else has chimed in on this thread. There's gotta be someone else who knows something about collapsed lifters or valvetrain stuff here.

 

[DissFigured]

Is it possible that there is no problem at all w/ the lifter / rocker and that I am hearing a noise related to another cause?

If the spark plug was out on one of the cylinders, would it make a tapping sound?

 

[tylerrocks]

Im suprised no one has chimed in either. i'm no expert but I think I can set a couple things straight. First DissFigured, are you sure the noise is comming from the under the valve cover and not a blown gasket(s) on the exhaust manifold? I assume you've checked the exhaust manifold bolts for tightness. A good way to check for blown exhaust gaskets is to use a length of hose, 5/16 or so, as a stethiscope. Hold one end to your ear and the other along the head/manifold gasket and the flange gaskets. To determine valve cover noise, use a longth of metal rod, all-thread rod for example, as a steth. Place your thumb over one end of the rod and hold your ear to your thumb, then probe over the valve cover with the other end. You'll hear some noise but it would be obvious if something were wrong.

Let me ask you, does the car drive ok other than WOT? how many times has it died on you at WOT? This sounds to me like a tuneing issue or perhaps a clogged fuel filter.

Lifters are the part of an engine that ride on the camshaft. Camshaft lifts lifters, lifters lift pushrods, pushrods actuate rockers, rockers open valves. The lifters can be found by removing the intake manifold. You can check for COLLAPSED lifters by placing a screwdriver on them and tapping with appropriate force using a hammer. They shouldn't depress.

Start troubleshooting with the least intrusive 'solution' to your engine. And obviously if the sound is really bad, like CLANKING, dont sart the engine, tapping is ok. I doubt your problem is oil pressure, especially if you,ve been able to drive around like this a couple times.

I guess thats it for now, good luck.

 

[DissFigured]

It has never died on me. It feels like it is going to die as if flooded w/ gas but then I let off the gas and it runs normal. It drives fine but feels a little weak. I think that may be bad tuning but the tapping noise perplexes me.

I removed the valve cover and everything looks very solid.

The header bolts all seem tight. I was able to crank them all down about a quarter to half a turn. The gasket on the header looks kind of nasty and the headers / bolts all look rusty for lack of a better term.

How much trouble is it to replace that header gasket?

 

[toolwench]

Thanks tylerrocks for chiming in, too. You added some great stuff I hadn't even thought about.

Another way to tell where the noise is coming from is simply listening to whether it's once per revolution or twice. Without hearing the quality of the noise, I can't be certain it's top end (usually twice per rev and more of a tapping) or bottom end (once per rev and more of a knocking). There's so many things the sound could be, without hearing it directly, it's hard to tell for sure.

The header gasket should be easy. Unbolt the header, remove the old gasket, put in a new one.

It does seem like you've got a tuning issue, too.

 

[DissFigured]

I had a guy listen to it. He described it as a knock (sounds like a tap to me)
It is once per revolution.

 

[toolwench]

Then, yeah, it might be a leaking header gasket. Or even a collector gasket. Or wait, you said it was at the motor. Did tightening the header bolts make the sound change at all? If the sound changed, it's definitely the gasket. If that didn't change it, it still might be the gasket or something else entirely.

I had a manifold gasket that wouldn't seal by tightening the bolts. I also once thought that my manifold gasket was the problem, but it wasn't...the donut at my collector was the problem.

I don't profess to be any kind of expert on this stuff. I only know what I know from my experiences on my own car over the years. I really thought there'd be a lot more people chiming in here.

 

[tylerrocks]

I would check for exhaust leaks first, if the bolts were loose there is a good chance you have blown a gasket. changing the gaskets can be a PITA but its definatly not difficult. oh, you might not be getting a good seal in the first place due to warpage, it's ok to run double thick manifold gaskets if need be.

 

[DissFigured]

OK, I will change the gaskets.

I didn't fire it up after tightening the bolts as I have not re attached the valve cover.
Dumb question. When you say manifold are you referring to the same thing I am calling the header?


I assume we are all talking about replacing the gasket between the engine, and the four pipes coming out of it? I call those headers. What is a manifold.

 

[tylerrocks]

OK, I will change the gaskets.

I didn't fire it up after tightening the bolts as I have not re attached the valve cover.
Dumb question. When you say manifold are you referring to the same thing I am calling the header?


I assume we are all talking about replacing the gasket between the engine, and the four pipes coming out of it? I call those headers. What is a manifold.

headers are tubular aftermarket exhaust manifolds. manifolds are stock castings but they are the same thing, yes. I would atleast start the engine before you decide to replace the gaskets, you may have fixed your problem.

 

[tylerrocks]

OK, I will change the gaskets.

I didn't fire it up after tightening the bolts as I have not re attached the valve cover.
Dumb question. When you say manifold are you referring to the same thing I am calling the header?


I assume we are all talking about replacing the gasket between the engine, and the four pipes coming out of it? I call those headers. What is a manifold.

headers are tubular aftermarket exhaust manifolds. manifolds are stock castings but they are the same thing, yes. I would atleast start the engine before you decide to replace the gaskets, you may have fixed your problem.