88 Pick-up, 22RE, Remanufactored long block just installed, no street miles as of yet. The problem is that I have a at random clatter that will come and go. It sounds like it is in the valve train, as if something was loose under the valve cover and just making contact every once in awhile. Engine temp makes no difference and it will last a few seconds to a minute or so and will go away. Does increase with engine speed and will happen at idle as well as higher RPM's. Pulled valve cover and checked for anything that could of been left inside but found nothing. Chain, guides, rockers, springs and valves all appear in good order. Will not make the sound long enough to pinpoint it. It is a very loud to moderate clatter, sometimes sharp and sometimes dull, much like a valve lash problem on one valve but all are adjusted to proper clearances. Don't know whether to crap or get off the pot but thought somebody else might of experienced the same problem. I do thank you for all the help you have been so far getting this thing going!! Any ideas or solutions will be appreciated because it sure has me baffled!!

 

This may or may not be it but. Tight valve guides can stick valves open, sometimes for a moment, sometimes for good, resulting in extreme lash, and clatter it will! I would put Lucus fuel additive in the tank ASAP. I've used Marvel mistery oil for many years but don't now how that affects O2 sensors. Maybe someone else here does.

 

One other thing is it will usually run a little rough when this happens.

 

Thank Kurt will use the Lucus. The engine does seem to miss a lick when noise occurs but then again I maybe to busy looking for the noise that I don't notice it!!LOL