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Hey Folks


My 87 307 has a knock at start up. I havent noticed it , however a mechanic friend of mine says he didnt like the sound of it.

Does the 307 make this kind of noise? It seems to run fine, and I cant hear any bad sounds when I race the engine.

Any thoughts would be appreciated
 

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94 FWB, 93 SDV, 94 FWB (sold), 90 Brougham (sold)
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So the knock goes away? How soon after start-up? What does the knock sound like?

"Rods, pins, and piston skirts give a classic double knock. The more massive the object the heavier or lower the note of the sound. Bad mains give off a heavy single thud."

"The oil thins out at it heats up with the running engine. As the oil warms the thinner viscosity results in reduced pressure, much as a result that the thinner oil leaks out of the clearances faster. So a failing bearing, most often a rod or pin, suddenly makes noise, which may go way if you bring the revs and thus the oil pressure up."



"do it the old fashioned way by cutting off a broom handle about 3 feet long and holding it to the engine block and your ear...listen to where th noise is coming from....but dont put it on anything rotating...thats bad.
Also put it on the valve covers.
Thatll help determine where the noise is coming from."





These posts are from the Chevy High Performance message boards.





Let us know what you find out, good luck!





Brian
 
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