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Mike@dw

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Discussion starter · #1 ·
Have a hollowing sounding knocking/rattling noise coming from the front of the motor (72 454). Appears to be coming from the pulley, belt, water pump area.

I have only owned the car for about a month, so I am not as attuned to its noises and creaks, but I am very sure this is a noise that has just recently arisen and is not right. It is loud enough that you can hear it with the hood shut from a few feet away.

Although I am new to chevelle's and 60/70 era cars in general, a have done my fair share of wrenching during my linfe. Just used to later model cars. So treat me kindly please :)

I felt a decent amount of play in the fan clutch shaft so I replaced that today hoping that is what was rattling/knocking, but no dice. Besides that I have done the basics of making sure nothing is loosing and rattling against something, but it is not that type of rattle anyhow. It seems to be rpm dependent but hard to tell for sure.

Car is running fine, motor feels strong and runs smooth.


Car has working AC. The AC belt seems visually a little off compared to the others. Has a little bit of side to side vibration when moving, but that is about the only thing that looks visually off. Just throwing that out there, not that I think it is the problem

Ideas for me to start checking? happy to take any needed pictures or video if needed.
 
The 454 in my 79 Chev knocks at idle and just off idle.
Has done this for years----over 10.

It is the fuel pump, so you might want to feel that thing while the engine is running.

Just tossing that idea out there for ya
 
Discussion starter · #7 ·
The 454 in my 79 Chev knocks at idle and just off idle.
Has done this for years----over 10.

It is the fuel pump, so you might want to feel that thing while the engine is running.

Just tossing that idea out there for ya
Thanks, I will look at anything thrown out there.

Did not get a chance to mess with it today, hopefully one night next week. I really don't feel the motor is knocking, hard to describe the sound. You would have to hear it.

Got two months to get all the little things sorted out. Taking it for a 2K mile road trip across the west for our Honeymoon :hurray: Pic below of the new ride

Image
 
sweet ride!
try the pulleys as stated above.....with engine off naturally, check the water pump shaft for wobble. I've not had a fuel pump rattle though I have seen this maledy described here...quite often actually.
You can shoot a video of this beast running too...post it here.
 
I've had alternator bearing give up the ghost and rattle and knock. Changed one out in the parking lot of Advance once (cheapie unit) didnt even make it out of the parking lot, it was rattling worse than the old one! You can try an automotive stethoscope to pinpoint the noise, but be very careful around the moving parts!
 
Discussion starter · #13 ·
Forgot I had a mechanics stethoscope and poked around with that for a bit. Could not pinpoint it to the water pump or fuel pump with the stethoscope and those things are pretty good about finding noises.

The more I look things over I feel pretty confident that the noise is coming from the crank pulley area. And my attention if focusing again on what appears to be a loose or misaligned AC belt. You think that could cause the noise at the crank? Temped to just cut the AC belt off and see if that does it. Just seems like a pain to remove all the other belts to remove the AC belt.
 
Make sure the balancer is not the culprit, or you could be left stranded AND have a damaged crank. A good friend of mine had one split at the keyway on his 454 and it sheared the end of the crank. It was rattling a bit too before it let go.
 
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