1980 350 small block, whats that noise

[84CUCV]

just sound like something not right. any help would would be great. here is a video.

http://www.youtube.com/watch?v=krh4DSMr1gM



thanks

 

[lectric80]

Not the best sound on the video, but I can't hear anything I can identify as an issue.

 

[Hogback Fabrication]

Not the best sound on the video, but I can't hear anything I can identify as an issue.

Agreed.

None of that sounds like a knock or lifter issue, it sounds more like a carb tuning issue to me.

 

[84CUCV]

OK , im not really sure. just has headers now. kinda loud. was taken with a crappy old sony. i was going by what my friend said. thanks i will take a look at the carb

 

[1980]

Check the intake gaskets & for leaks around the carb. Just a guess.

 

[84CUCV]

ok thanks

 

[Bent77]

An easy way to check leaks around the intake is to use carb cleaner w/ the straw. the engine will change rpm if it sucks it in.

 

[noJeepshere]

just has headers now.

i did that with my 81 k5 when i swapped out the stright six for the 350. i ended up burning some valves and later that caused a piston ring to fail.

 

[84CUCV]

i did that with my 81 k5 when i swapped out the stright six for the 350. i ended up burning some valves and later that caused a piston ring to fail.

really?? wonder how that works

 

[noJeepshere]

really?? wonder how that works

my late mechanic friend explained that the complete lack of back pressure somehow (it was beyond my understanding at the time, kinda still is.) let the exhaust air mingle in the header tubes and get really hot. and it ran kinda rough until i put the exhaust on. something about scavenging, the other cylinders helping to pull the fumes out of the cylinders. and that caused a minor meltdown of the valves, which ruined compression but not quite enough to be readily apparent. that overheating that burned the valves also hurt the piston ring, and failure. i actually wish that i had kept the straight six, i think it was a much better engine for that ride as light as it is. (it tipped the scales at the dump just over 3400 without me) beside the point. he never recommended running an engine without an exhaust.

 

[noJeepshere]

also, the 350 was a '79 smogger with all that crap removed and '67 camaro z28 heads put on. i have a pair of shorty headers on it too. i had to drive the rig 3 miles to the exhaust shop and the damage occured (my guess)