Quote:
Originally Posted by Smallblock454
Well, i think you found the problem. 
Hope there is no excessive damage to the engine casing. Sometimes these chains can do ugly things
How does the IMS look?
How do pistons, rods and valves look? |
The casings seem fine, I haven't discovered any damage on them so far, which is great.
IMS looks great too. Rods look fine, pistons have slight damage but seem reusable, I'll have to do measurements though. Several valves are bent. I'll upload pictures later.
The question is, why did the chain snap? Tearing a dual row chain apart like this requires quite a bit of force. However, I think I found the answer for that.
Inside the scavanging pump, that's a crack right there:
Yep, the rotor is broken.
It clearly picked up something which seized up the pump and hence the camshaft, that's why the chain snapped. I can make out the piece that's now melted in the pump housing.
But I have no idea what it may have been and where it came from. So far I haven't found anything that came loose, missing bolt, etc. So I'm puzzled. Anyways, the engine obviously needs to be taken apart to the last bolt.