I have a 90 Graduate with 30,000 miles. Since I bought it from the Alfa dealer in 1992, the car runs quiet when it is cold. As soon as the heats up it sounds like a singer sewing machine. It seems to be coming from the intake and exhaust valve train. I also loose a quart of oil every 500 miles but the compression tests are good. I tried reshimming the valves to spec, cold twice per the manual and there was no change in the sound or oil consumption. I've heard other Alfas and they don't sound like this one. Any ideas?