well '09 the cooper s I bought yesterday with a misfire, (150k miles) has no compression in cylinder 1. At least we found the misfire! I should add that the codes were for misfire all cylinders but I was told thats not always right anyway.

We pulled the valve cover and the rockers are ok (sometimes they can spit out and that valve stops).

Not sure what it could be. Should I pull the head and how long does that take? Used motors are like $3k from what I can see... but reconditioned heads are $800 and if its just one bad valve, thats a cheap fix at least for parts...

Also, I think this is an R56, is it?

 

It could be anything. Could be burnt valves, could be head gasket, could be cracked head, could be worn rings (unlikely tho, some compression would exist) or even a hole in the piston. You can apply compressed air into that cylinder (should be in TDC) through spark plug hole and listen where the air is coming from:
1) Exhaust - exhaust valve is shot
2) Air intake - intake valve is shot
3) Open expansion tank / radiator cap - if the air is coming through there then it is either a head gasket or a crack in the head
4) A lot of air is coming from the oil passages - rings or piston are shot.

Either way - head removal is inevitable, seems to me.

 

OK thanks. I am thinking its in the cyl head as well.(Although, since I am new to minis, do pistons fail often?)

Those refurb heads online any good? Do people rebuild their head (if not broken)?

I am hoping to save this car and not have to part it out (and lose money in the process)

 

Pistons would be probably the last in terms of probability. If the head itself is fine (no cracks, good cams, good journals) then it is totally rebuildable by machineshop (or you can do it yourself, if you have some tools and skills). It still will cost you, so if you are trying to save money you can play a lottery game called "lets buy used head and just drop it in and pray it will work fine". But you can pay even more if you are not lucky.

 

I’ve seen reports of broken valves and broken pistons related to no compression in one cylinder. My suggestion would be to NOT buy any parts until you get the head off.