(14-08-2017, 04:50 PM)Alan Wrote: The interesting thing is the broken studs. Studs don't just break, my guess is it's a fatigue failure. If the clamping load in the joint is less than the cyclical loading of the valve train or combustion pressures etc there will be fatigue implications. If one bolt goes, the rest will follow. The cause is loss of clamping load in the joint, either insufficient tightening (and I don't believe Charles would do that), or the bolts have worked loose somehow. Maybe vibration or relaxation of the gasket if fitted.
That said, hydraulic lock is still a possibility. Quite often there's no residue of water or fuel because the engine was hot and by the time you get to it it's evaporated. The studs will tell. If it's a fatigue failure it's option one. If it's not, them it's either a piston stuck in the bore or it's hydrauliced.
No gasket, just 515. All tightness checked just prior to the weekend.
My money is also on a stud letting go leading to a daisy chain of breaking studs, arrested only by the through bolting on the valve chest side.
After sitting for 3 hours parked up at Rolt corner no water had leaked back into the bores, suggesting to me that a hydraulic lock was probably not the root cause (yes, the rad was still full)
Charles