# Unidentified noise in my 455



## Jonwilkerson (Jul 10, 2009)

OK, I'll make a disclaimer, this is my first Pontiac, a 1966 gto with a freshly built 455. At any rate, while idling, there's a high frequency hum or whine (that's as good as I can describe it) which goes away upon revving the engine.





. (goes to youtube). You can hear it at about 1:10 and 1:40.

We've torn down the front of the engine twice trying to track down the problem. We first thought that it was built without a thrust plate, but it was there. We also ended up replacing the fuel pump eccentric. But it did not change the noise. Is this noise just characteristic of these engines? Or, is this something to be concerned about?


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## Rukee (Feb 8, 2007)

Try to remove the belt and run it for a few seconds to see if the noise is still there. That will tell you if it's something on the inside or the outside of the engine. Also did you notice any abnormal wear on the inside of the timing cover, timing chain, harmonic balancer?


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## Jonwilkerson (Jul 10, 2009)

Listening with a stethoscope, it's only obvious underneath the timing cover.


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## Rukee (Feb 8, 2007)

Did you take the gear and chain off when you took it apart? Any abnormal wear on anything? Is it a chain? Or a gear on gear set up?


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## Jonwilkerson (Jul 10, 2009)

It's a chain setup and it's all new. All told, it probably hasn't been run over an hour.


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## Rukee (Feb 8, 2007)

Is it a double roller or original style chain? Lower balancer pulley tight? I'd remove the belt anyway to eliminate those components as suspects.


If it still makes noise with the belt off I might be inclined to tear the oil filter open to look for filings.


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## Jonwilkerson (Jul 10, 2009)

It's a double roller. The pulley is as tight as I can get it without turning the engine. I'll take the belt off and see what happens. Thanks for your help.


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## Eric Animal (Oct 28, 2007)

What cam/distributor gear are you using? You could be hearing gear noise transmitted thru the cam shaft to the front of the engine...put the stethescope on the distrubutor. I could barely hear any whine in the video. Nice looking build up also!! Eric:confused


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## jetstang (Nov 5, 2008)

:agree I was thinking a vacuum leak on the intake, which it may be, but those don't come and go.


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## 66tempestGT (Nov 28, 2009)

i dont have a clue but i enjoyed listening to the tape "twice"


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## 05GTO (Oct 6, 2004)

I think it's coming from the core support or radiator, when you placed your hand on the core support to listen to the timing chain cover I could not hear the rattle.

The engine sounds good,


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## jetstang (Nov 5, 2008)

66tempestGT said:


> i dont have a clue but i enjoyed listening to the tape "twice"


The tape? 8 track or cassette?


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## 66tempestGT (Nov 28, 2009)




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## Jonwilkerson (Jul 10, 2009)

Eric Animal said:


> What cam/distributor gear are you using? You could be hearing gear noise transmitted thru the cam shaft to the front of the engine...put the stethescope on the distrubutor. I could barely hear any whine in the video. Nice looking build up also!! Eric:confused


Thanks a lot.:cheers We're hoping it will all come together pretty soon. We used a COMP cams 270H. And an MSD distrubutor.

It's more noticeable in the shop than it is on the video. Also, it really doesn't sound sick or anything. It may be a characteristic noise that we just aren't familiar with.


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## Jonwilkerson (Jul 10, 2009)

05GTO said:


> I think it's coming from the core support or radiator, when you placed your hand on the core support to listen to the timing chain cover I could not hear the rattle.
> 
> The engine sounds good,


BTW, disregard that old, crappy core support. The one we're going to use is at the body shop. I will make sure and check on what we got set up now though. Thanks for the comments.


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