There are 32 studs holding each head; pictured on the right are 62 of them. There are 3 different stud lengths used:- a)=4.375", b)=5.5" and c)=6.0". Shown in the table below is the position of each type; the numbering is taken from the front.
Cylinder heads are identical, so can be fitted to either side of the block. Studs on the inlet sides run in reverse sequence from 'A' bank compared with 'B'.
Problems encountered with extraction are noted below:-
-
10 of the 12 snapped studs were screwed into threaded plugs - the result of earlier problems. The majority are on the off side ('A' block) which, no doubt, accounts for the difficulty in removing it.
-
the screwed repair plugs were of either 10mm or 12mm diameter; none appear to have been installed perpendicular to the block face. These studs had been slightly bent to allow head attachment.
-
the majority of the snapped studs are of a material compound far harder than original specification and have proved too hard to drill. Enquiries have suggested that a batch of studs of this metal was on the market some years ago and has given similar problems to those currently being experienced.
Final resolution to the stud problem has been put on the back-burner until the state of the rest of the engine has been ascertained.
