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engine knocking noise diagnostic help required

G

GT350

Member
ok got a 67 mustang with a 351w auto fired it up hell of a deep knocking noise oil pressure is 60 psi cold oil is clean looks like quite a fresh engine.
So i took the motor out thinking im going to have to get the crank done .
the flexplate was loose could physically moved it by hand can this cause a heavy knocking noise when engine is running? reason i ask is before i start stripping the motor down im thinking this might be the problem any thoughts anyone :beer
 
If the flex plate was loose.....was the tranny also loose? That very well could be the noise. Was the noise/knock a steady rhythm or pattern? Steady and deep normally indicates a main or rod.
 
"AzPete" said:
If the flex plate was loose.....was the tranny also loose? That very well could be the noise. Was the noise/knock a steady rhythm or pattern? Steady and deep normally indicates a main or rod.
Click to expand...
more of a pattern,the tranny was tight
 
When the crank broke in my Dad's '72 F100/302, it sounded just like that......for about 2 mins. before it went bang doing 75 mph.
 
If the sound is rhythmic and increases or decreases with speed, possibly a rod bearing (based on what you've said about it). It would sound metallic, and I hate to say it but, like someone tapping with a hammer. You can do one more check before a full pull down. Pull the pan off and check each rod. Use the handle end of a hammer and rap the tops of the rod caps. You should hear a "thud". If you get a "clunk", bad rod bearing!


p.s. The reason I hated to use the phrase "like someone tapping with a hammer" is due to an old mechanical repair joke.

Mechanic: So what does the noise sound like sir?
Customer: Like a little man tapping inside the engine with a hammer.
Upon receiving his bill with a description of repairs done is a note: "Took hammer away from little man"!
 
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