R53 Engine Swap - Crank but no start diagnosis

Update

I took the timing cover off and replaced the timing chain, the guide rails, the tensioner, and the cam sprocket. Made sure to have everything aligned. Checked everything thrice.

Also put on an OEM cam position sensor.

Buttoned everything back up. Still no start. Getting a slightly louder sound when cranking (almost like partially burning fuel), but it still won't run on its own power.

I checked compression again, and now I'm getting 40-60 psi in all the cylinders, which is more than the 15-30 they were reading before, but of course still way too low.

I cleared the codes to see if anything new came up, and now I'm getting no codes at all. (how long would it take for new codes to show up if they were going to?)

At this point I'm at a bit of a loss given everything I've checked and replaced this far.

The only other thing I thought to try tomorrow will be to put new gas in. It's been sitting for about 6 months, and though I did put fuel stabilizer in back then, it might still have gone bad?

Any other suggestions??

 

Well, after a leak down test things are looking pretty bleak.

Cylinder 1 - 40% leakage (no noticeable hissing anywhere)

Cylinder 2 - 85% leakage (obvious hissing air coming from dipstick tube and oil fill cap)

Cylinder 3 - 50% leakage (slight hissing air from dipstick tube)

Cylinder 4 - 85% leakage (loud and obvious air from dipstick tube and oil cap)

Based on these results I'm assuming piston/piston ring/cylinder walls are the most likely culprits, meaning I'm probably not getting out of this without another disassembly. Probably going to start with an attempt to get a refund from Redline on the engine.