I am looking for some guidance, opinions and recommendations, not necessarily in that order, from the wealth of knowledge that exists on this site. So my 86 2.5 has been developing a knock (no, not just a ticking) in the last couple of months, along with smoke exiting the tailpipes. I also noticed that the last time I changed the oil a few months ago, which was very black, the new oil became very dark within a few days afterwards with very little driving. This is not a DD and it currently sits more than it is driven. I have also noticed that it seems to have a lack of power from just a few months ago. I have not done all of the tests that everyone is probably thinking to themselves right now, compression test, leak down test, etc., because I haven't the tools and have not had the chance to get to it. My question is, do you think with what I have told you that this 2.5 may be worn out? The odometer reads around 168K, but I am not sure it is even the original engine. You can also see from the attached picture that these two dark circles on this piece of OSB were created when I fired it up. It was placed about 18 inches behind the tail pipes and appears to be oil spots. I will try to get a video of it running and post it if anyone thinks that will help.
Do you think I need to start looking for another 2.5, or could I be missing something else other than what I already fear is the obvious? Thanks.