Had to pull the heads off my VR cos #6 cylinder was full of coolant. Had them reco'd (not that it could fix the issue if it's something else) and according to my engine builder now I have to space the rocker arms so the valves don't stay open. He wouldn't go into any sort of detail on how the hell I actually measure the correct spacing for this cos he didn't have an original head thickness to work off. This motor has been worked a little or more correctly flogged a lot before I bought it at the wreckers. It's got yella terra 1.7 ratio roller rockers and had extractors, dunno if it had different management if that has any bearing on the condition of it. I should have acsess to some standard rockers but they're not adjustable either.
Can anyone guide me through this? getting the car to a mechanic is not an option.