Anyone ever suffered this before?
Not on a big block but on a V50 II though. The skirt on the r/h barrel dropped into the crankshaft, broke up and locked every thing solid - and I mean ‘solid’. I wasn’t able to get the engine apart for further investigation. In your case I’m pretty sure that the piston broke up first, the bits got between the piston and the barrel producing enough pressure to crack the skirt.
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It looks like a lack of lubrication, but why only one side?
If it were timing issues I would expect to see crown damage, of which there is none.
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I agree on the lubrication. I haven’t yet dug deeper but wondering if the big end shells have spun and blocked an oil way, or, if it was a blocked breather that lost me a litre of oil, or because the failed piston created the extra crankcase pressure.
New to me second hand engine too. I had removed the sump and renewed the oil and filter. Hadn’t actually done 10 miles so a bit disappointing.
Edit: …and I haven’t removed the other barrel yet, although I did do a warm engine compression test (on returning home) for the working cylinder that still read at 165psi.
I have a pair of cast iron liner 950 barrels and a pair of new pistons if you are interested.
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Are the rods on the right way round?
Oil spray Holes
Sump gasket fitted the wrong way round?
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Essentially these pistons are the same as on A Spada.
There are no oil ways or holes in the pistons.
Lubrication relies solely on splash from the sump, so probably oil level.
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Maybe the fault was pre existing.
By the way some shells don’t even have holes
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Yes I’d be interested. Maybe you could PM me with the details?
As I mentioned, I’ve yet to dig deeper to see if there’s more damage so will need some time to figure out what is economic.
Looking at what I’ve taken apart I’d guess I’m the first in there.
Good thinking but I have another bike with the same engine and I’ve serviced it many times so know which way the gasket sits.
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Good point. I’m thinking a possibility is that the check valve in the breather box jammed and sucked the oil out rather than the damaged piston pressurising the crankcase and being the cause of the quick oil loss.
It’s a possibility, but I didn’t notice the cracked liner when I had the sump off to clean it out and fit a new filter prior to installing it in the frame.
That’s about the worst seize I’ve ever seen. Hope that didn’t happen at speed?