what weight oil are you running??

I'm using 5w40 Valvoline full synthetic on the current 4.2 motor. In the past I was using 20w50 Valvoline race oil, but when tearing the motor down Dave Dalke found that the wrist pin bushings were pretty hammered, and thought it was probably from the oil being too thick. I've also added a mechanical oil pressure gauge under the hood to check pressure at cold start up and hot idle every once in a while.

David

15w50 Mobil 1 Synthetic in my 3.8.

I just rebuilt my engine 500 miles ago. I broke it in with 5w30 motorcraft semi synthetic. I want to change the oil this weekend to get out all of the prelube, etc. that goes with a new rebuild. I think I am going to start running full synthetic. Has anyone had any issues doing this on a fresh motor?

90sc35thann said:

I just rebuilt my engine 500 miles ago. I broke it in with 5w30 motorcraft semi synthetic. I want to change the oil this weekend to get out all of the prelube, etc. that goes with a new rebuild. I think I am going to start running full synthetic. Has anyone had any issues doing this on a fresh motor?

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You will be fine with the full synthetic. Synthetics from the major oil companies which are petroleum base stock oils.

You would even be good with the AMSOIL Signature Series oil too.