I have no idea what this thread is about! More like a time wasting exercise! Please lets see some useful contribution for prosperity- some technical input. You can do all this on most social media sites!

 

Better yet tell why you posted on a thread that was started and ended in November 2014? Do you have an issue you are trying to resolve?

 

Spam maybe?

 

Great suggestion- what's your best idea?

 

Drive by poster!

 

With a knock like that, your mechanic might be able to locate it with a stethoscope. Also I have heard knocks like that that was motor or transmission mounts gone bad.

 

I remember this post I even commented on it but something came to mind that I would like to share, I had a 81 corvette with the usaul 350 v8,I had put it in storage as I would be away working for about 3 month.I was very excited when I returned to drive the car after such a long time but it had this same noise,my mecahanic said same thing bearings gone! How could that be on such a low milage car that run fine when I parked it! Mechcanic said lets try one more thing and he removed air cleaner and ran some decarbon cleaner through the engine while it was running at a high idle.Worked perfect no more noise. His explanation was that carbon will "grow" and that was what happened there was not enough room when the piton reached tdc and caused the piston to "knock"

Randy

 

Really, carbon grows when vehicle is not running?

 

Is it a car or a tree?

 

Diamond in the rough?

 

Carbon build up was a problem but more so in the old carburetor days.

Fuel injected engines are just much cleaner inside and it would difficult to build much carbon unless the car was running rich for a while.

If you find out what the noise was please let us know.
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+1

1981 Corvettes had such low compression that they couldn't detonate on 87 octane fuel, never mind 91. Carbon in the combustion chamber was not the issue, probably a sticky lifter just like SBC's have been doing since the 50s.