Quote:
Originally Posted by safetyfish
I fitted the belts.
Before taking it apart the general concensus was that I did not tighten the belt tensioner pulley properly when I changed the belts. (Ducati Master Technician helped me to take the thing apart)
Big surprise, everything was exactly as it should have been.
Pulleys were torqued as per spec and were still good when we opened it up.
belts were tensioned correctly
The timing marks on both the horisontal and vertical cylinders all alligned perfectly..... The cuase of the failure could not have been the belts.
Before the failure, the bike started first time. It idled perfectly. No backfire. Linear power throughout the rpm range. No stuttering or stalling. It picked up nicely when accelerating from one gear too low. The only difference too that bike was that I removed the intake restrictors, which gave it a louder intake growl. That is it.
I am currently looking at the cost of replacement head, conrods, piston, valves, rollers etc. ooouch!!!
SF
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I am amazed the belt driving the camshafts with the failed valves was still intact.
looking at the pictures the inlet valves are still in place and there is quite a bit of hammering damage to both the piston and the head indicating the engine did not come to an instant stop. This damage would have taken place whist the engine was still rotating.
It would be reasonable to assume that if the engine was rotating after the exhaust valve heads where broken off, the inlet valves, if still operating, would have also been contacted by the flying broken internals and themselves also been contacted and broken off
I can see how the the water in main journal theory would be possible. In my experience (not with bikes) water in the sump normally results in highly emulsified oil/water mix, which still provides a degree of lubrication, obviously this is not ideal but probably would avoid a catastrophic failure of the main bearing shell.
I have only ever seen one engine where the shell/bearing was ejected from the bearing cap allowing that sort of clearance increase and that was a 600HP v8 which did not allow it to seize/lock and 'spat' it out instead