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Discussion Starter #1
There's a loud knock coming from (sounds like in the middle of the engine) but I and no one else can tell either. I thought I had a lifter not pumping up so I replaced them and still the noise. The old lifters wasn't wore terribly where they hit the cam so i don't think my cam is shot. maybe one of my valves is burning. Please help this simple noise is driving me crazy.
 

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Hey Ozz,

Start your engine and run it for 2 or 3 minutes on a sunny day, then kill the engine and pull the dipstick out and see if there is any glitter, shineys in your oil, if there is pull the engine and fix the bottom end.

You can use a long screw driver to pin point the noise.

Larry
 

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Discussion Starter #3
Somthing tells me it's not the bottom end. it only does it at certain rpm's. or at a certain torque. I've been told it could be the flywheel. but I adjust the valves and tone changes. I've also been told it could be a bent crank. Time for a new motor huh.
 

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I once had a loud knock from the engine, only at certain RPM and conditions, swore that the crank was out of it, even had 2nd and 3rd opinions, Yanked the mill out of the Camaro, flipped it over, pulled the pan, started to check individual rod bearings, then when I grabbed the flex plate to roll the engine over I found that the flex plate was loose to the crank, ARRGH !!!! wasted that weekend.

To pin point your knock, pull one plug wire at a time, if the noise is less then you have found what cylinder to look at, another thing you could be running into is the piston slapping the top of the head, would be most noticeable at high RPM with little load.
Lifter or valve train noise would be a light tick noise where the bottom end is a knocking.
 

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We just went through this with a Muskrat. In the end, the cam bearings were tear drop shaped!

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Mark

1992 Firebird 355/Six Speed (Soon to be LT1)
1991 RS 350 / 700-R4
1987 Toyota Pickup 383 / 500 + HP 10.963 @ 119.95 Slicks / 11.997 @ 114.23 Radials
"Speed KILLS, so drive a FORD and live forever!"
http://personal.lig.bellsouth.net/~racer383/
 

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Discussion Starter #6
thanks for your help guys. I'll check them cam bearings, I'll probably put new bearings in it along with a new cam.
 

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If a rod bearing goes, it could allow a piston to hit the head.
Pull the pan and check the bearings.
David

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Check my web page for First Gen Camaro suspension info:
David's Motorsports page
First Gen Suspension Page
67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Can Am Vintage Racer
 
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