Hey guys i know this is a diesel site but i have a question about a jeep and was wontering if anyone could help. I have a M38 A1 1953 jeep and just yesterday it stared the dead knock it sounds like its coming from the front of the motor. It hasent lost oil pressure and i think it has solid lifters but i am not sure. Its a 4 banger by the way let me know if anyone can help.

 

Does it have a cam-driven fuel pump? Might have lost the spring and the arm is slapping around. That sound will mimic a spun bearing or rod knock.

Best is to get in there with a mechanic's stethoscope and see if you can isloate where the noise comes from. Pull the rocker cover, do a compression check, and perhaps even pull the pan. Best to check it out or it may go BOOM. Don't be surprised if you find that the bores are worn beyond repair. Seems to be common on the 4 cyl. Jeep motors. Never seen one that wasn't in fact.