Pistons fouling on valves

Would you be able to hear it?
 
I've noticed my belts slipped a few teeth due to lack of tension.....
 
Haven't had the engine running yet, just turning over. I have retimed the pulleys and tensioned the belt since...
 
I'm a little bit scared.

NOT NECCESSARILY...
 
I had a cam belt slip a tooth or 2 on the Escort a few years ago when it backfired on startup and there was a ticking sound at idle and low revs...  Do NOT show up on a compression test and was persistant until I took the head off and took it to a head place...  Was only slightly bent and not really visible except that half the seat was shiny and half was not....  And it was not a big cam either - only a mild one to suit the gas research..
 
If a valve is hitting DO NOT START THE ENGINE or you will bend a valve (or 4) or worse... You should feel it when turning over the engine by hand GENTLY...

On another note however, i've tensioned up my belt and i can twist it roughly 3/4 of a turn, is this too loose??? 
 
Cheers guys

Cheers matt as always you're the man with the answers! 
 
I can't seem to tension mine up to half a twist, its really annoying me.
 
Yep I turned it over by hand and it was all good, i've just gone and turned it over with the key a few more times, each time checking the marks and the crank pointer and the cam pointer are lining up perfect every time. 
 
A question about your bent valves, did you notice any performance decrease or was it purely through the ticking noise that you tried to locate the problem.
 
Thanks again guys.