Knocking Noise From The Engine

Does that Dino front-end look lighter or is it my imagination? Maybe there is something very heavy in the boot tipping it up? Well, as you can see there is no engine in my coupé! In these times of austerity I thought I'd save money on the ever increasing price of fuel and fit a Fiat 500 engine in there instead! Ok ok - I didn't want to be in this position, but there has been a strange knocking sound coming from the engine when warm (not when cold), noticeable at idle as well so I took the car for a check-up and as no answer could be found with the engine in place, it had to come out and has been dismantled. There are no obvious signs of what is causing the noise - the crank is off to be crack tested and measured along with a number of other items. There was a mark on one of the shims, but this is not the culprit. One of the previous owners told me the engine was completely rebuilt about 8 years ago and this can be seen - the kilometerage of the car is around 30,000 and this seems to be true as, apart from the rest of the car being in great original shape, the crank has not been ground and is only lightly worn. I'm waiting to see what the verdict will be in the next week or so. I am also toying with the idea of fitting high compression pistons while it is all in bits.