Well I just finished my b16 longblock swap into my 00 si. Its been running for about 2 weeks now. I live on the mississippi/alabama state line and went to the nopi nationals this past weekend. From here its around a 4 1/2 to 5 hour drive. On the first night after arriving i checked my oil and no oil registered on the dipstick. The car ran fine and also vtec engaged. Thats where i got confused. At first i thought the wrong dipstick was in the motor. But upon draining my oil that night i found there was only 2 and 1/2 quarts of oil in the pan. (vtec still engaged). So i changed the oil and put 4 quarts in and when i got back to mississippi i found the motor lost 1 quart of oil. There are no apparent oil leaks from the back or front of the block. I asked a few people at nopi and they suggested it was the rear main seal. I also have noticed that my clutch does not grab when it usually does when the car warms up...... sorry for the life story but does anyone have any suggestions on what it could be......there is no white smoke coming from my exhaust or crankcase breather.