I have a motor knock that I can't diagnose and neither can a few friends and family. The knock is worse on start up and is less of a noise as the engine warms up. It seems like the strongest noise is on cylinder number 5. The motor is a 72 351 windsor that's stroked to 408. I pulled the motor before this because after my camshaft blew up at 5500 rpm because of having the wrong oil pump installed and had a knock then. The cam gear had a couple of broken teeth along with the distributor gear having teeth blown too. After replacing the distributor gear and limping the car home I could hear a slight unidentifiable knock. I pulled the motor and replaced the following; cam, lifters, oil pump, timing chain and pulled pan and wiggled all connecting rods thinking that whatever noise I heard; if it were a rod bearing or wrist pin; would be identifiable by wiggling the rods. However, all seemed tight so I moved on and after discovering the cam gear had a few missing teeth I thought that might have caused my noise.
Upon reassembling the motor with the new parts and after breaking in the cam I still heard a slight knocking noise that increases with rpm. The noise starts off pretty easily heard and after some running and warming up it becomes very hard to hear. Someone who isn't used to hearing motors would probably not be able to hear something wrong. I've put my ear all around the motor with screwdrivers and stethoscopes and cannot quite identify the noise. The strongest area where the noise is is on cylinder number 5 at the front of the motor. I think that I can hear the noise strongest while listening to the intake runner with a screwdriver at the base close to the head. It doesn't seem to be a rocker or pushrod as I have moved the front rockers and pushrods to the back along with the nuts.
I built a break in stand just for this reason thinking that there might still be a noise. I don't want to reinstall the motor into the car with this noise and am looking for your help. My possible ideas are bad lifter(s); even though they're new, or maybe wrist pin. I know I should have checked clearances in the bearings but thought that whatever noise I had heard would be easily identifiable.
408 windsor, trick flow 225 heads, edelbrock rpm air gap intake, MSD ignition setup, hooker super comp headers, speed demon 750 double pumper.
Upon reassembling the motor with the new parts and after breaking in the cam I still heard a slight knocking noise that increases with rpm. The noise starts off pretty easily heard and after some running and warming up it becomes very hard to hear. Someone who isn't used to hearing motors would probably not be able to hear something wrong. I've put my ear all around the motor with screwdrivers and stethoscopes and cannot quite identify the noise. The strongest area where the noise is is on cylinder number 5 at the front of the motor. I think that I can hear the noise strongest while listening to the intake runner with a screwdriver at the base close to the head. It doesn't seem to be a rocker or pushrod as I have moved the front rockers and pushrods to the back along with the nuts.
I built a break in stand just for this reason thinking that there might still be a noise. I don't want to reinstall the motor into the car with this noise and am looking for your help. My possible ideas are bad lifter(s); even though they're new, or maybe wrist pin. I know I should have checked clearances in the bearings but thought that whatever noise I had heard would be easily identifiable.
408 windsor, trick flow 225 heads, edelbrock rpm air gap intake, MSD ignition setup, hooker super comp headers, speed demon 750 double pumper.
