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I have had constant lifter noise from one cylinder (tap not excessive) for last 8 months. Did oil change with Penrite HPR 30 oil which did not reduce tapping noise. Noise did not improve as oil pressure increased. Whilst driving yesterday on country road a loud knock started. Pulled over immediately. Knocking is from at same cylinder area as previous tappet noise. Engine is running on 7 cylinders. I can also hear a gas popping noise as if valves not closing correctly.
Any initial thoughts would be greatly appreciated. What initial diagnostics would be recommended to investigate/isolate problem?
Regards Kevin
From: Lake Arrowhead - Georgia > 72 Base Coupe & 74 BB Roadster
Originally Posted by Kevin71C3
I have had constant lifter noise from one cylinder (tap not excessive) for last 8 months. Did oil change with Penrite HPR 30 oil which did not reduce tapping noise. Noise did not improve as oil pressure increased. Whilst driving yesterday on country road a loud knock started. Pulled over immediately. Knocking is from at same cylinder area as previous tappet noise. Engine is running on 7 cylinders. I can also hear a gas popping noise as if valves not closing correctly.
Any initial thoughts would be greatly appreciated. What initial diagnostics would be recommended to investigate/isolate problem?
Regards Kevin
While I know you are thinking its a lifter or valve be sure you check for exhaust leaks first.. I was sure I had a bad lifter or push rod which turned out to be a cracked exhaust manifold. it sounded like metal on metal knocking. Hopefully its something simple.
From: Lake Arrowhead - Georgia > 72 Base Coupe & 74 BB Roadster
Originally Posted by fotyfobravo
While I know you are thinking its a lifter or valve be sure you check for exhaust leaks first.. I was sure I had a bad lifter or push rod which turned out to be a cracked exhaust manifold. it sounded like metal on metal knocking. Hopefully its something simple.
Thinking more on this...... do you think you may have wiped a lobe on your camshaft?
Is it popping through the carb or the exhaust? Might be a valve sticking open....follow previous post and check rocker arm action. Pull valve cover and crank engine ( don't start it ) and observe rocker arm action. Report (pictures help) back to forum and let us know what is going on.
Unscrew the Oil Filter and have a look inside. If its full of Metal then its time to pull the Motor and see what went wrong. If it looks good, You could still have some sort of part broken in the valve train, or some sort of tuning issue.
Thanks everyone for your advice. As suggested, I took both valve covers off and discovered cylinder 6's had a rocker arm which was not aligned to the valve (twisted 45 degrees). It was still attached but had 3 pieces broken off. All pieces were found next to valve. See images. Replaced rocker arm, cup and locking nut. Rolled push rod on glass and is not bent or damaged. Googled how to adjust hydraulic lifters. Further investigation of other rocker arms identified that ALL needed adjusting. One in particular was very sloppy cylinder 1. I think this has been the initial tappet noise in engine I have been hearing. All back together and running smoothly (and much quieter). I think I got out of that one cheaply. Thanks again for your help.
Is the oil you are using a multi weight, if not - I would be careful.. it can take the oil an extra 5+ minutes to reach operating temperature vs engine temperature when it's cold out.
See if the rockers are moving as they should.
Excessive knocking noise
