Igor, I'd be critical of the Victa production engineer if he has people tightening the bladeplate retaining bolt by restraining the crankshaft by the flywheel retention nut, and not even using a torque wrench on the bladeplate end. I tighten the blade plate nut on my Victa by clamping the blade plate. It's easier than taking the top cover off and more importantly, it avoids wrecking the engine. Putting about 30 lb ft of torque through a crankshaft that only develops 4 lb ft when the engine is running? That is just irresponsible.
I agree that your explanation is possible of course, and would mean that the entire mess-up happened here in Australia at the Victa assembly plant, but I'd rather think better of Victa than that. Two serious quality control procedural errors are required for your solution to apply: using a completely unsuitable way to restrain the blade plate when fitting it, and failing to use a torque wrench for a safety-critical process where assembly torque is critical. In this case it looks as if the bolt-head was rotated at least two full turns after it came up tight, so Victa may have some problems with its training and production line supervision as well.
Having said all that Igor, I have to say your explanation is not just plausible, it's elegant as a solution to what we've seen. I still don't understand how a soft bolt was used, though.
Last edited by grumpy; 22/04/11 04:37 AM. Reason: Expand comments
