Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
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Is it normal for me to be able to hear my valves knocking? It sounds like it was and exhaust leak but they told me no leaks anywhere and that the ticking/knocking were my valves.
__________________ 1986 Camaro 350/700r4
1992 Caprice 305/700r4
Last edited by chrisblazzer89; 03-08-2008 at 05:50 PM.
It's not common to happen out of the blue.
Take off the valve covers and see what's up.
First thing to do is put a straight edge over all your rocker studs. Make sure they are all the same height. Takes 30 seconds and rules out a stud being pulled up.
Do this with the engine warm. Restart the car with the covers off, and relash your valves hot. Wear a raincoat, you're gonna get wet.
I'd be suspicious of an exhaust leak as well though. You shouldn't be able to hear your valves/rockers when running.
I have seen ticky lifters on real high mileage engines, comes from a wiped cam lobe. It will ticky tick, you will adjust, a little later ticky tick, repeat.
Get short length of 1/2" garden hose. idle engine when warm. listen at the valve covers, if it is a lifter loose, you will hear the sound only in one spot. Move around the engine compartment, (stay away from belts or fan), noise will be louder one place, quieter others. Could be front, back, top, or bottom. Where the noise is loudest is were the trouble is.
Ahh yes, right... no EFI in '84. I've had a flatulent brain lately, you'll have to excuse me.
And yes, I agree on the colapsed lifter. Its not.
Does the noise get better (quieter) or worse as it warms up? Same? Does it stay at the same rate, or get faster as engine speed increases? Go away as engine speed increases? Does load (ie. driving VS parked) make any difference?
I had a lifter tapping on my l03 for about 500 miles. It just stopped all of a sudden for some reason???
The thing ran fine, so I dontknow if it was a lobe going away or what. I had a plug that was really lean, though, so I wonder if it was an intake lobe.
Last edited by InfernalVortex; 03-10-2008 at 03:20 AM.
Collapsed lifters are a wives tale, but dry lifters aren't. If there is some gunk built up in the lifter oil passages, it's possible they aren't filling with oil properly, causing slack in the pushrods/rockers. Might be worth running a can of engine flush through it, and then changing the oil. I assume you have good oil pressure? Also, lifters/rockers shouldn't make a knocking sound, but a ticking sound, as if someone were tapping the engine block with a screwdriver. Exhaust leaks can vary from a slight ticking sound to a loud popping sound, depending on how bad the ehaust leak is. Rod knocking has a distinctly more "metal on metal" sound, where exhaust leaks sound more like a poof of air.
__________________ North Texas Third Gen Association 1988 GTA 5.0/M5/3.45 LSD, T-Tops, Digital Dash, Leather - Current Ride 1983 Firebird S/E - Stripped 1995 Chevy 1500 5.7 Ext. Cab - Daily Driver
I dont know if they have air injection in 84 but one of the check valves in the air tubes by the manifolds on my TPI went bad and it was making an exhaust leak sound.
I tightened all the exhaust manifold bolts and then pulled those valves off and they only pass air one way, it passed air both ways. I just lucked out on that one.
You rev your car REAL high lately? Could be a loose rocker or pulled out stud (if you have pressed in studs). My dad used to pull out the studs all the time in his 86 LG4 until they pinned them I think.