Engine knock help please
Thread Starter
Intermediate
Joined: Jun 2015
Posts: 49
Likes: 4
Engine knock help please
I bought a 76 L48 350 automatic all original in May been working on it and driving it since. I just developed a knock from the front of the engine the alternator is new I assumed water pump replaced it still knocks the alternator support bracket was missing I replaced that and the alternator and it still knocks I see post about a fuel pump knock and my car has been harder to start lately having to pump the peddel several times to get it to start I don't want to throw unneeded parts at it any way to check? Although at 40 years old anything I replace is probably needed.
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,481
From: Southbound
Cruise-In II Veteran
Take it to a shop and let them diagnose your knock. My definition of a knock is an internal engine noise. You're chasing external engine parts. Paying for a professional opinion could end up saving you money in the long run.
Thread Starter
Intermediate
Joined: Jun 2015
Posts: 49
Likes: 4
Thank you Mike I will do some searching around its hard to find someone good these days I will contact a local vette club for a recommendation
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
No, use a 4' piece of 5/8" garden hose to locate the source of any noise. Plug one of your ears, hold the hose to your other ear, then use the other end of the hose to probe for the sound source. As the hose will block out all surrounding noises you'll locate the source very quickly.
Thread Starter
Intermediate
Joined: Jun 2015
Posts: 49
Likes: 4
No, use a 4' piece of 5/8" garden hose to locate the source of any noise. Plug one of your ears, hold the hose to your other ear, then use the other end of the hose to probe for the sound source. As the hose will block out all surrounding noises you'll locate the source very quickly.
Burning Brakes
Joined: Aug 2003
Posts: 1,060
Likes: 19
From: Ocean Springs, MS
St. Jude Donor '07
No, use a 4' piece of 5/8" garden hose to locate the source of any noise. Plug one of your ears, hold the hose to your other ear, then use the other end of the hose to probe for the sound source. As the hose will block out all surrounding noises you'll locate the source very quickly.
I thought I had a bad lifter on my C3 and the rubber hose helped me determine the AIR Pump check valve going into the LH exhaust manifold had a small hole in it. Easy fix, I removed the non-working pump!
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Thread Starter
Intermediate
Joined: Jun 2015
Posts: 49
Likes: 4
Now confused
I used the rubber hose and thought it was the timing chain before I dove into that job I removed both belts so I could get in there safer when I started the engine no knock I put the power steering belt back on and got some knock maybe a quarter as loud as with both belts could it be the front bearing? All the belt pressure pulls to the left side the knock seems to go away with increased rpm only hear it from idle to about 1500 rpm