[Spridgets] Oil Pressure Relief Nut

[rrengineer at dslextreme.com]

No, I am not referring to myself after the high oil pressure fiasco this
past weekend.  What I am referring to is the nut for the pressure relief
valve.  Does anyone know what size it is?  The largest wrench I have is 24
mm.  I have the distributor out, the oil gauge line off and the number 4
spark plug wire removed to have room to swing a wrench be cause the
aluminum back plate sticks out far enough beyond the nut and it is close
enough to the backplate that I cannot get a socket on the nut.  If I can
get it off I am going over to APT (5 min from my house) and compare
springs with a new and old spring and inspect the cup.  Maybe buy all new
oil pressure relief parts.  So, give me an excuse to go buy a new wrench. 
What size is it?
Mike MacLean
60 Bugeye (problem child)
56 BN2 (the never ending project)