Dan
Premium Member
Registered: 22nd Apr 02
Location: Gorleston on Sea, Norfolk
User status: Offline
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As above.
Need to speak to somebody who does engine failure analysis, metallurgy or anything similar who can give me some pointers on an offshore generator engine that's failed.
Does anybody do it?
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ChrisBoom
Member
Registered: 6th Dec 06
Location: Highland
User status: Offline
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Any pictures of the failure?
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3CorsaMeal
Member
Registered: 11th Apr 02
User status: Offline
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Steve could probably do a full motorsport Internet analysis if you get a photo on your phone.
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Dan
Premium Member
Registered: 22nd Apr 02
Location: Gorleston on Sea, Norfolk
User status: Offline
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No pictures, but I need to speak to someone who deals in analysis or metallurgy.
Do you do something similar chris?
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craig8
Premium Member
Registered: 31st Dec 04
Location: Glasgow
User status: Offline
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What appears to have failed and what are you trying to find out?
E36 328
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Dan
Premium Member
Registered: 22nd Apr 02
Location: Gorleston on Sea, Norfolk
User status: Offline
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The cause of the failure. It's an engine I've rebuilt a few weeks ago. Looks to me like its detached from the piston and punched a hole in the block. However the cap has come off the main bearing and both big end bolts have sheared the heads off.
There's no bends to either bolt but neither have a nut on them when found. Which to me seems odd as both bolts wouldn't have loosend at the same rate. Meaning every rotation the cap is going to flex the opposing bolt.
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Dan
Premium Member
Registered: 22nd Apr 02
Location: Gorleston on Sea, Norfolk
User status: Offline
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Half of the piston is still in the top of the liner. Looks a clean break right across the center of the gudgeon pin. Which in 12 years of doing this I have never seen a rod come out of the block without pulling the whole piston out and smashing it to pieces.
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craig8
Premium Member
Registered: 31st Dec 04
Location: Glasgow
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So the top half of the piston is still intact and sitting in the liner? Quite a strange one that. Is it free to move or seized?
Any chance of there being play in the big ends?
Bolts were 100% tight?
Not questioning your ability at all mate but it does happen sometimes. Was it a clean break on the piston or ragged?
Any spots on the break that look darker than others?
E36 328
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Dan
Premium Member
Registered: 22nd Apr 02
Location: Gorleston on Sea, Norfolk
User status: Offline
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It's clean from the pictures. I'm yet to see the engine.
There's a mark on 1 side of the rod that looks like a bolt could have been pulled through on the piss. (Half moon shaped heads). But I'm 99% that didn't happen, as I have documents signed during the build to witness the tightening etc. So me nor another experience engineer would have allowed a bolt to wind down tight before clicking off.
Bearings are all new. Crank was measured, bearings were plastiguaged.
It's a real mystery. The piston being at top in exact half seems odd to me.
I'm thinking it's seized in the bore. The little end looks stretched to me.
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craig8
Premium Member
Registered: 31st Dec 04
Location: Glasgow
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Like you say it sounds like it's seized and the piston has broke at its weakest point, clean break would indicate that it's most likely not a manufacturing fault in the piston.
Must be pretty annoying not getting to be the one to strip it down and see everything first hand too, sometimes that's when you get the best clues as to what's went on
E36 328
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Dan
Premium Member
Registered: 22nd Apr 02
Location: Gorleston on Sea, Norfolk
User status: Offline
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I will get to strip it. But ATM it's stuck in North Sea. Loo
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