1931 Pickup Engine Knock
- Thread starter Garagekulture13
- Start date
mass A man
Well-known member
I could hear it in your video--this may sound inane to some, but could it be a harmonic vibration of something else loose on the truck? Seems you really know the A engine and inspected it fairly thoroughly. I'm at a loss-sorry.
john charlton
Well-known member
Pleased you changed the oil pump although it was a good repair I could not have put that back in the engine . The video does show your problem with clarity actually the scenery looks very English except you are on the wrong side of the road !!! A very unlikely longshot exhaust pipe harmonic rattle in the rear clamp . I would remove the spark plugs and spin the engine over on 12 volts to see if you can locate the knock location .You wont harm the starter motor they are a very rugged unit as long you do not use for extended periods . My gut feeling is that is a top end noise but did not show up when you shorted out the plugs . We are all baffled I think this is a job for Sherlock Holmes ( and Dr Watson) !!! Keep us updated please .
John in Suffolk County England .
John in Suffolk County England .
nkaminar
Well-known member
Definitely linked to the engine. Not a rod bearing or main bearing. If you play back the video at 1/4 speed you can hear a gear noise associated with the knock, so I would look at the gear on the crankshaft and the camshaft. Check the plunger and spring at the front of the cam gear and as Crosscut said, check to see if the cam gear nut is tight and that the fiber gear has not come loose from the steel hub.
It is knocking all the time and not the clatter when low torque on the motor that would be indicative of a rod bearing. Nor is it the deep thud of a main bearing when accelerating.
Another possibility is the oil pump drive gear on the camshaft or on the shaft that is vertical to drive the pump and distributor. Since the oil pump was cracked that may indicate a problem there.
But at 1/4 playback speed you can hear the gear noise.
If the screw holding the distributor is too tight or if there is something tight in the distributor that may be causing this knock. Take the distributor out to check for excessive drag and don't over tighten the screw when putting it back in.
I would advise not to drive the car until you find and fix the knock.
It is knocking all the time and not the clatter when low torque on the motor that would be indicative of a rod bearing. Nor is it the deep thud of a main bearing when accelerating.
Another possibility is the oil pump drive gear on the camshaft or on the shaft that is vertical to drive the pump and distributor. Since the oil pump was cracked that may indicate a problem there.
But at 1/4 playback speed you can hear the gear noise.
If the screw holding the distributor is too tight or if there is something tight in the distributor that may be causing this knock. Take the distributor out to check for excessive drag and don't over tighten the screw when putting it back in.
I would advise not to drive the car until you find and fix the knock.
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