So, I had noticed what sounded like rod knocking in my 2004 Nissan 350z with 140k miles. IT got progressively worse, and I went to look around. I ended up finding all of my oil gone, seemingly due to the infamous Jiffy Lube incompetence at installing oil filters (it fell off with a flick of the finger).
At the suggested of a more mechanically experienced friend, I added 3 quarts of 20w50 conventional oil, and 2 quarts of 85w90 conventional gear oil (after checking there was not reaction to the mixture).
The sound all but disappeared as expected, however, it makes me wonder -- how temporary is this? I had probably driven about 80-160 miles with 1-2 quarts of oil. At the time of drainage (some days after noticing the problem), I got about 1/2-3/4 quarts out, and my collection for the leak had collected another 1/16 quart or so over ~15 hours of measurement. The oil smelled burnt, at 1500 miles (synthetic, high mileage 10w40).
I imagine I should ditch the car ASAP, as I do not have a space to use an engine hoist to rebuild the engine, nor the money to pay a mechanic to do so. Is it possible the rod knocking was only normal due to the lack of oil, or is the engine genuinely trashed? I imagine the latter, but input is appreciated.