The Ford Barn

34Pietenpol · 05-11-2019, 05:26 AM

Looking for opinions while acknowledging how difficult this request is. Skyline Chapter engine man, Reggie, put the stethoscope to the block to try to ID what sounds like a piston slap. Noise isolated to between #2 and3 cylinders, was most notable above 1300 rpm and with full advance. Went away or became very muted at the same rpms but with full retarded ignition. Engine has good compression, pulls hard on the road, no metal in the oil and no exhaust smoke. It runs cool enough when advanced but will overheat with full retard and road speeds of 35-45 mph.

I can understand detonation pinging from running too advanced but this sound is not pinging. It is a slap. Reggie does not think it is a con rod or crank bearing cap issue or babbit wear.

So, slap, between 2 and 3, higher rpm and accelerating, goes away at full retard. Any suggestions for troubleshooting to narrow this down? Thanks in advance!

05-11-2019, 05:26 AM	#1
34Pietenpol Member Join Date: Aug 2014 Location: Shenandoah Valley, VA Posts: 65	Mail Truck Engine Noise Looking for opinions while acknowledging how difficult this request is. Skyline Chapter engine man, Reggie, put the stethoscope to the block to try to ID what sounds like a piston slap. Noise isolated to between #2 and3 cylinders, was most notable above 1300 rpm and with full advance. Went away or became very muted at the same rpms but with full retarded ignition. Engine has good compression, pulls hard on the road, no metal in the oil and no exhaust smoke. It runs cool enough when advanced but will overheat with full retard and road speeds of 35-45 mph. I can understand detonation pinging from running too advanced but this sound is not pinging. It is a slap. Reggie does not think it is a con rod or crank bearing cap issue or babbit wear. So, slap, between 2 and 3, higher rpm and accelerating, goes away at full retard. Any suggestions for troubleshooting to narrow this down? Thanks in advance!