Most of you already know that I had the motor in my vette rebuilt to a blown head gasket and antifreeze getting in with the oil. The engine rebuilders told me to put 1500 miles on the car with regular conventional oil which I followed to the T. The only problem I was getting, was a lifter making a little noise on cold starts, which they were getting ready to look at. But now I have a little over 1500 miles on the fresh motor and I just got done putting Mobil 1 10w30 Synthetic in it. I prefilled the K&N filter with oil and I started it. The bearings hit hard for about 3 seconds then as it went into slower idle I could hear the bearings knocking, just like they did when the antifreeze got to them, what would make them do this. I am going to take it back to the engine rebuilders but I just wanted to hear everyones thoughts on this? Did I put synthetic back in it to quick? Because when I changed it at 500 miles I put Castrol 10w40, and it only made a little noise and went away, now it does it all the time. Any and all feedback is greatly appreciated. By the way when I started it back up with the synthetic my oil pressure was at about 28.
Justin
Justin