Thanks Bob H!! Is there two plugs, one in the end of both rocker shaft? If is, I know the plug you mean. What is the whole meaning of this plug? If the plug is missing, what makes the oil light turns off right away after start when the engine is still warm? I hope this is the solution to my problem, but if it isn't, do you think is it possible that the valve which is situated with oilfilter is leaking and thatswhy it takes so long to get oilpressure up if some of the oil have run away through the oilfilters valve. And thatswhy the light turns off normally when the engine is still warm because the oil haven't had time for running away. So do you think this is possible?