M30 spitting Fire but won't start

[pianist]

Long story short.. I have acquired the engine from my stepdad so it is known good running engine, it was standing now for about 5 years in which time I had some work on head done like valve seats recut, new valve stem seals etc., basically nothing major, when putting it all back I may have put cam timing advanced by one tooth I say I may have because it was a long time when I did it but that is how I remember it, any way when I used to own 323i advancing the cam used to give it an extra oomth and I read somewhere also that with stock cam it may work good so I thought I’ll try it on here as well. I didn’t know at a time that ignition timing is not adjustable on these engines but surely it should at least start right? Well it is spiting some fire out the exhaust ports (no exhaust manifold) and it seems to want to start when turning but never does, also shot the MAF meter off three times now (backfired).
So before I will start massive job of checking/putting cam timing back to original I thought I’ll first ask gurus on the zone if they had any similar issues with it and what I should look/check for.

Thanks

[fixedwheelnut]

One tooth on a chain is a long way, probably bent the inlet valves a bit allowing blowback through the intake, check the compressions then a cylinder leakage test.

[pianist]

well I was careful about it, I did turn the engine by hand two or more rotations just to be sure it is not touching the valves after I put the chain on so I think valves should be ok. I can check the compression anyway, but would that one tooth would through the timing so much that engine wouldn't start? I thought it would be at least running rough or something.

[Speedtouch]

The backfiring could indeed be caused by the timing being too far advanced, and/or the wrong air:fuel ratio...

https://en.wikipedia.org/wiki/Back-fire

[pianist]

Looks like I better star taking things apart it is going to be such a ball ache since the engine sits only like 5mm from radiator

Thanks for your input guys