Engine Sounds

[schovil69]

New engine runs great. That is, it idles and revs as expected. There is this noise, though, that the cause of which eludes me. The sound of this noise is dead on for loose rocker arms. It has a distinct metal on metal click type of sound you would expect from loose rocker arms. It is loudest to me when standing next to the passenger fender with the hood up. Dad believes there is no difference in sound from anywhere in front with the hood up. Standing next to the driver door, on the other hand, with the hood up this sounds appears to be coming from under the vehicle.

I have lent my ear to 1/2" drive breaker bar with the other end placed on each valve cover, the oil pan, the timing cover, the front of the intake manifold, and the distributor cap with the engine running. The noise appears loudest in this manner when the breaker bar is located on the front of the intake manifold.

The loose rocker arm theory is a dead horse been thoroughly beaten. Another potential cause for this sound could be an exhaust leak at the manifold-head or manifold-exhaust pipe interfaces. These have also been checked and rechecked...no leaks found there. My next thought for the potential cause of this noise was the distributor drive gear on the cam so I pulled the distributor and found nothing abnormal there.

My next plan is to 1) Pull a valve cover and the distributor then using a priming tool reverify the oil pump is doing its job by pumping oil to the rockers...and presumably everything else, 2) Remove intake manifold to inspect roller lifters, 3) Remove timing cover to inspect for timing chain interference. I may reverse the order in which these inspections take place for 2 and 3. One potential culprit could be the water pump pressing on the timing chain cover. I was wary of this on assembly and took action to remedy any potential interference at that time but I may have missed something.


Are there any other potential sources for this noise that I'm not currently considering.