What the heck is this noise?

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hobo
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What the heck is this noise?

Post by hobo »

I can't figure out what is going on here:

https://youtu.be/V9t_K7f9QeI

Noise pitch seems to fall as throttle increases. Vacuum hoses checked and all seem to check out. I would think a bearing or belt would rise in pitch with throttle. Any ideas?
1967 D-100, /6, 3 on the tree

gww
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Re: What the heck is this noise?

Post by gww »

might get a couple ft. long hose, close to your ear then move around with it to locate source.
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Re: What the heck is this noise?

Post by EGroscup »

Certainly sounds like an intake leak to me. I am going to guess intake manifold gasket and/or carb mounting gasket.

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Re: What the heck is this noise?

Post by PwrWgnDrvr »

When throttle opens, vacuum decreases, therefore intake leak pitch goes down.
Spray starting fluid around carb base, manifold joints, etc. If it sucks in through a leak, engine rpm changes and you can thereby locate the leak.

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hobo
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Re: What the heck is this noise?

Post by hobo »

PwrWgnDrvr wrote:When throttle opens, vacuum decreases, therefore intake leak pitch goes down.
Spray starting fluid around carb base, manifold joints, etc. If it sucks in through a leak, engine rpm changes and you can thereby locate the leak.
Thanks, will check. It definitely seems to be coming from that area. I pointed a hose at all the pulleys and it didn't sound like they were culprits.
1967 D-100, /6, 3 on the tree

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hobo
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Re: What the heck is this noise?

Post by hobo »

It was the carb mount gasket. How rare (but how lovely) it is when the fix is $3 and 10 minutes. :Thumbsup
1967 D-100, /6, 3 on the tree

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