I wonder if what your hearing wrist pin slap?
At low rpm you will hear a double slap, once when the piston reaches TDC and then again when the cylinder fires, and the sound tends to get so fast with increased rpm that it seams to go away.
To prove this out If you pull the plugs one at a time at idle this noise will go away by 50%, and that’s enough to nail it down to a wrist pin issue.
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs!
And he was not talking about 1/8 or 1/4 mile ETs!
1) 1940s 100% silver 4 cup tea server set.
Two dry rotted 14 x 10 Micky Thompson slicks.
1) un-mailed in gift coupon from a 1972 box of corn flakes.
Two pairs of brown leather flip flops, never seen more then 2 mph.
Education is what your left with once you forget things!
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