velox

Thanks for many good suggestions! I came to my boat to inspect more, but will not start it now as it appears that there is again plenty of diesel in oil! The oil level has risen quite a lot from where I filled it yesterday, and oil viscosity seems to be very thin. Maybe there is also some other leak in addition to injection pump (which had definitely previously leaked, and should not leak now). Could this also explain the noise? Just to clarify: the previous problem I had was with injection pump, not the fuel lift pump, which also has been replaced couple of years ago.

Oil pressure is very good, no problems with that. When increasing engine speed, the noise speeds up as well, and when running at around 2000rpm it isn't at least heard as clearly.

Does anyone have a good guess of what could be making this sound on my BMC 1.8? Could it be loose timing chain, something with pistons, or something else? The sound is louder on the left side of the engine, maybe at the front but I'm not quite sure. I just recently had fuel pump renewed, as it had leaked diesel into the oil during the winter. This sound probably has nothing to do with this, but it appeared at the same time. engine_noise2.mp4