I had a strange one this morning. I recently rebuilt the head on my M103 motor. I have driven it 4k miles since the rebuild. I had not done anything to the rockers for the rebuild. Previous to the recondition, my valvetrain would tap for a second or two on startup until oil pressure comes up. Then it purrs like a kitten. After the work, it still does the same.

It was colder than usual this morning. About 18-19 degrees. I had changed oil on Saturday afternoon with Mobil 1, 10w-30. Now this morning, it did not stop ticking after startup. I reved the motor a couple of times and the ticking did not go away. I shut the car off, restarted, and the ticking was gone.

A friend of mine has a Mercury Tracer (Mazda 323) that does the same thing. Sometimes after startup, the valvetrain ticks. It will keep ticking until the engine is stopped and restarted. Then the ticking is gone.

What could cause this to happen?

How do I diagnose which set of rockers is causing the ticking?

__________________
Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)