I was away for a 4 day fishing trip. I haven't driven the car in 4 days. I decided to take the Vette to work today. When I fired it up it sounded odd. A tight "tapping sound" somewhere around the driver side valve cover/exhaust manifold. It really sounds like it's coming from the area of an exhaust leak or a valve/tappet is clanking.


NOW UPDATED WITH PICTURES BELOW:

RECENTLY UPDATED WITH FREE HAPPY ENDING INCLUDED!


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Check the oil first, when it's low, hydrulic lifters can make tapping sounds and usually starts with which ever one happens to have the loosest tolerance. If the oils fine and pressure is good, then carfully drive it, listening to the engine for more or louder sounds, stop if you get a bad feeling. If oil checks out start checking for an exhaust leak first (the easy stuff), they are often mistakin for valve problems.

 

If you can, check bolts at the exhaust connection to the head--a loose exhaust header sounds like a metallic clicking noise.

 

 

Ohhh Brother...Warpage maybe???

I got home just fine. But, the motor seems to be @ 75%
I re-tightened all the header bolts to the heads and still, metal clapping/tapping sound. Grrrreat. My wife & I just bought a new piece of property earlier today and we're trying to figure out who to build our new house, two small babies at home (I can't start the engine now because I'll wake them up ) and the engine is gettin' all goofy now...

I could feel air coming out of the area of the head/exhaust header area, but the headers are bolted super tight. I suspect perhaps the header flange is either warped or I have a crack? Or a blown head gasket???

D@mn...A little too busy with life right now to be tearing the engine apart. Looks like the car cover is coming out & time to disconnect the battery for a few months.....Sadly, just in-time for summer

I'll post findings.


Andy

 

The header bolts can be tightened and you can still hear the metal popping noise- look at the 1,3 plugs at night with no lights... if in that area, you see a little light flash- the gasket is blown and you can easily replace... but if the car is running @ 75%... then that's another issue. Good luck.

 

You got it. Here's what it looks like:




But wait...
Here's what it REALLY looked like...



KaPOW!!! Look closely, the burned area have been charred and burnt for quite awhile....




Does anyone know of a better manufacturer for header gaskets?
Will I need to apply some type of gasket sealant?

Andy

 

You'll definatly have to do some investigating, but... I wouldn't think the worst just yet. Block/head warpage or cracking is unlikly, it takes something serious to cause that, like overheating, or freezing the coolant. Check the exhaust first, it won't cause that power loss but maybe it felt weak cause you were babying it and nervous driving it, it's hard to judge power at part throttle. If it really is down on power that much then it probably lost a cylinder, valve train wise, blew a lifter or cam lobe, bent pushrod, ect. A blown head gasket can cause you're problem too, it makes that tapping noise and ruins the effected cylinder's compression. Is there sweet smelling and moist exhaust on that side? If so that's it, but they don't always break thru to the water jacket's. Check the spark plugs too, it woulden't be the first time a plug worked it's way loose. If you have no luck with the exhaust use a mechanics stethescope to poke around, you can narrow down the problem that way, but same rules apply about running the engine, be easy, and if it starts to sound worse, stop imediatly. BTW, don't buy a mech. s-scope, just use a long ratchet extension, put the end just below and in front of your ear canal, kind of just in front of the lobe, on the bone, this gets the sound to your ear drum the best. Poke around various areas were the sound is coming from, pressing the tip against the spot you want to hear. If you've never done this before it's surprising how much moving it a 1/2 inch can make a differance in what you hear. Good luck and keep us updated.

 

I gotta type faster...

 

Yikes! This is what I was fearing. I'll replace the header gasket & check plugs first. After that I am going to use your technique to iron out all possibilities.....D@MN! The motor only has 7,000 miles on it

 

Oregon 80- don't worry about all of that- as they say.. "it's all good", but get 2 paper gaskets(from autozone, cheaper than getting the nice ones on-line)- soak them in water for 24hrs.. don't let them dry- just put them both on right away.. you'll be good to go. While you're at it- go ahead and get two more gaskets to do the other side... it's only a matter of time! Good luck.

PS- my gaskets looked worse than that!

 

I do mine by getting regular white paper gaskets and putting a thin coat of black RTV on both sides around the ports. Re-tighten after the first heat cycle and then again after a weeks of driving. Never any leaks.

 

Doing it tonight. I'll report the results

 

I'll have to look at this solution too.

I have continuously developed an exhaust leak due to the header gasket cracking between the two centre ports on the left bank.

thanks for the tip.

 

Okay...

Unplugged the battery, tore out the alternator, took the valve covers off, removed spark plugs.
I did a quick inspection of the plugs= they looked great all nice light tan & clean (like campfire marshmallows when they're ready! ).
I then hooked the battery back up & turned the engine over to verify that the rockers & valve train was working as supposed to. Yep. They were all popping up and down happily. Checked the valve clearance w/ feeler gauge. All normal & perfect tolerance.
So the internal componants of the engine seem to be chugging along as required by internal combustion standards

After talking to the good people at Stans Headers (in Auburn WA) I was happily instructed to simply apply a very, very thin coat of Hi-Temp Red Permatex gasket sealant onto both sides of the gasket & re-install the header to the engine. I did that & tightened the headers nice & snug. Hooked up the alternator & hopefully didn't over tighten the alternator belt. I am always curious as to what is "too tight" or "too lose." But, that's another story...
Took the car out for a speed run for about 20 miles. Pulled off an exit ramp in the Columbia River Gorge. Sat on the ramp & stomped on the gas & roasted the tires for 60 yards. Hopped out of the car with my flashlight to check for any oddities..."HOLY SH%T, there was a motorcycle cop right there just 50 feet away from me " I was certain he was going to ride over & give me an exhibition ticket right then & there. But, he didn't. Probably figured "what in the hell is an old corvette doing way the hell out here, hood open w/ a flashlight doing?" Thankfully, he just tore off down the ramp to probably snag a speeder. WHEW!

Got, home & re-tightened the header bolts, which I am happy to have done as they had already losened up a little.

Stans also encouraged me to check & re-check the bolts over the next 3 weeks. After that, I'll never have to check them again for 20 to 30 years (on average).

Happy ending!


Andy

 

This is exactly what happened to me and I thought it was a loose rocker. Set the valves twice and then realized that 2 header bolts were missing. By that time the gasket was blown. I bought a set of Percy exhaust gaskets and am installing them tonight. These are 3 layer gaskets that supposedly will never blow..

Wade