89IROCZ

I have a pretty bad valve tap on the drivers side... it taps pretty badly and cna be heard from the interior or exterior of the car, but it is only when the car is cold. Once the engine warms up, it goes away. i heard somewhere that it could be the timing then, and that retarding it slightly might fix it. Is that possible? If not, my best friend knows how to, and has the tools to adjust valves. If I do adjust them will that have any side effects on the computer at all???

Thanks a lot.

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1989 IROC-Z
350c.i. TPI
rebuilt 700R4 with shift kit
3'' Monza Pacesetter cat back exhaust (minus the muffler)[SOUNDS OF THIS ON MY WEBPAGE]
new dual cats
3.23 Posi rear
hypertech chip
under drive pulleys
adjustable fuel pressure regulator
K&N Air Filters
Excalibur alarm, keyless entry and remote start
new:
struts, shocks, bearings, distributor, cap, rotor, alternator, battery, regulator
245 ZR16 50 Tires, Rotors and brake pads all the way around

Go to my webpage to find out more about it.
You can also see pictures, and hear sounds as well.
http://go.to/iroc-z

AOL IMer: JRShotliff

Blade

Well I'm sure there's LOTS of other people that can answer your question also...

I would take the valve cover off and figure out exactly which rocker is making the noise. You might also have a bad lifter that bleeds down too much when the car is sitting. Also the nut could've backed off causing too loose a valve lash. I would try to re-set lash on that one valve with the engine running. Back it off until you hear the rocker arm tapping. Tighten is very slowly until it completely goes away. Then give it another 1/2 turn. Put the valve cover on and test it out for a few days... if it goes away then it was just valve lash that needed to be set. If not, you might have to replace the lifter corresponding to that valve.

p.s. Also see if the rocket nut on the valve is very easy to unscrew. You'll notice this when u set the valve lash. If it is, you might wanna get a new nut since THAT's probably what's causing the problem. The nut needs quite a bit of effort to screw or unscrew on the stud.



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92 Z28 L98 350
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Ported and polished heads, ported stock TPI base, ported plenum, Comp Cams XR270HR-10 cam (lift .495/.502 duration 218/224 lobe separation 110), Edelbrock TES headers, LT4 valve springs, Crane AFPR, Flowmaster catback with LT1 style tips, MSD coil & wires...

"Take that auto, drop it in first, hold the brakes, stomp the gas and grin from ear to ear! :-)

Engineboy

Are you sure its not a small exhaust leak somewhere.

When the engine warms up the metal expands causing small ex. leaks to go away.

Just something to check.

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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3

Guest

I second the exhaust leak, thats more than likely what it is.

If you dont have exhaust gaskets on there (thats the way they came from the factory) then check to make sure the bolts are tight, they back out sometimes.

JETHROIROC

My vote's for the exhaust leak as well. Check the tightness of the manifold bolts before you go pulling the valve covers (some of them may even be broken).