Hey guys i am getting a repeditive high note knocking comin form my rb20det which is coming from the centre of the motor. Would this be pistons posably no.3 and 4. is there any chance that it could not be the bottem end?? the knock goes up as the rpm does. The engine it standad running a cooler , rb25 turbo and standard boost. Any ideas ?? its goes to the shop on monday but some advice would be great. Thanks