89 CRX si
I have my newly built 1989 D16A6 running well and have accumulated 2300 miles at the present time. I went with forged CP pistons at .020 overbore and stock rods. The head was freshened up as well and milled .010 and I have a Y8 head gasket to increase the compression. After the initial break in with Penzoil conventional oil 10w 30 I have put in Mobil 1 10w 30 synthetic for the past 2K and have changed oil 4 times with no particles in the oils. I have a concern with a knock I cannot identify even with a stethoscope. The knock I'm hearing is well after warm up and after a short trip and is only at idle rpm. It seems to be up top the best I can tell even though I know noise can travel and I have ruled out timing belt slap. At this point I think it could be the rocker shaft bridge or the cam cradle. Is there a possibility that either of those area's are expanding due to heat after extended operation and creating wider clearances for either the rocker shaft or the camshaft?