Cambelt tensioner bolt for 1.8t conversion

Hey all.
I'm am really struggling to get the bolt forthe cambelt tensioner on my 1.8t conversion.
I have the 16v pulley from a mk2 gti but no bolt volkswagon were no help to me. So I am wondering if anyone has a part number for it. Or if there is just simply a bolt that will do the job. My conversion needs this before it can get underway please can someone help me.
Cheers stevie

i just used a bolt i had laying around 17mm head one not sure on thread