Rebuilt a 99-01 B20B from a honda crv (High Compression) and put it in a 1991 honda crx. successfully swapped it and was running for a while. When the weather got cold engine had a hard time starting up and after a week or two when starting the car engine had a knocking sound. I do not fully know what is going on with it, but i may have an idea. Something might be loose inside the head. The knocking sound is coming from above the engine it doesn't seem to be coming from the block. So a loose engine part may be loose but need help to figur it out. barreratoby7@gmail.com here's my email if you need to hear the kocking sound.