I tend to agree with Calisto on jumping straight to leak down test as there is symptoms you might overlook should you not do compression test.
Dynamic compression losses: Leak-down is static (engine not turning), so it doesn’t show what happens under real cranking conditions.
Valve float or timing issues: These show up only when the engine is moving, not at TDC with no motion.
Sticky rings or valves: Might seal well under pressure but not during cold starts or low-speed cranking.
Intermittent issues: A leak-down test is just a snapshot it won’t catch problems that happen occasionally.

 

Ok, the engine is out and has been stripped completely, we’re talking naked! The cam is showing some pitting and two pistons are showing signs of damage on the skirts. Also all the ring lands are completely gummed up. It’s off to the machine shop for a line hone, deck the block and head, bore to 20thou, the crank is straight so is the head. I’ve gone for hyper-eutectic piston. Is anyone interested in me doing a vlog of putting Humpty Dumpty back together again😀