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Discussion Starter #1
my 1971 makes an occasional popping noise when idling, everything else shows things are good, its just I'm trying to figure out all this, still learning when it comes to older engines








and with lights









sorry for the lighting issues, its really dreary in fl right now
 

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Director Region 19 Owner of the KLRMino
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I could be an exhaust leak.

I can’t remember if this is the right way but you can take brake cleaner and spray it around the exhaust manifold ports and if your idle bumps up then that’s where the leak is.

It was either brake cleaner or propane to help find leaks, I can’t remember
 

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I could be an exhaust leak.

I can’t remember if this is the right way but you can take brake cleaner and spray it around the exhaust manifold ports and if your idle bumps up then that’s where the leak is.

It was either brake cleaner or propane to help find leaks, I can’t remember

NO WAY you should spray anything flammable, like brake cleaner or propane, around the exhaust manifold. Think you're thinking of doing that around the intake manifold to look for an VACUUM leak.
 

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Um, yea, brake cleaner on intake for vacuum leak test.

I use a piece of heater hose to my ear (about 3 feet) and the other end pokes around the engine bay to pin-point the source of the noise. Usually gets me pretty close.

From the video though, sounds like exhaust leak. If that's it, when the hose gets close I guarantee you will know it!

Joe
 

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I do what Joe does, use a piece of 3/8 hose and listen for leaks.

I also don't like the idea of spraying flammable liquids around the ignition..
 

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In working at a Chevrolet dealer in the mid 70's through the early 80's we saw a fair amount of the pop noise. Once on a brand new pick up right of the carrier, cam shaft wiped a lobe or two off.

My past experiences with a vacuum leak is you should hear a squeal or high pitched whine that gets worse with higher RPM,Maybe check to be sure the intake bolts are tight. An occasional pop leads me to think that the cam is starting to wipe off a lobe. Chevrolet had paid for a lot of cam & lifter replacements in the mid to late 70's.

My 2 cents,Mike
 

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I had popping with my 350 but that turned out to be spark plug wires being too close to headers and shorting out from time to time.Installed clips to keep wires away from headers.
Fly like the wind
 

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Discussion Starter #8
to be honest im starting to think it was the fuel system, it was hard to get any pressure at first from the system after sitting for a year (without gas) ill tinker with it tomorrow
 

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Discussion Starter #10
did find a possible issue, fuel line from tank to pump was leaking slightly, will be fixing tonight, also someone cut the old vent line behind the door
 
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