CM870 liner failure

[Rawze]

Setting aside that it might have been after-garbage parts or non-oem head being used for a moment. Assuming it WAS all oem parts and head for the sake of discussion ...

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If you did not replace the wrist-pin bushings with new .. especially on a heavy-haul engine, then it will send a piston thru the block in a hurry if they are even 0.001" out of spec. The highest point of wrist pin bushing wear will always be between the 11'oclock position and the 5'oclock position when the rod is standing straight up.

I discuss this a bit at 5:50 in this video...




If this is the case though, the wrist pin will have heavy scarring and step wear in it where the connecting rod ate thru it. The damage to the wrist pin will be obvious.

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Alternatively ... Something to check. It may not be what happened but is always a possibility ...

I have seen that happen a few times before where the person did everything right, there was no excuse for the engine to fail at all. They were super-meticulous, all OEM everything, new head, liner height right, good programming, ... you name it.


case#1: After some extensive digging ,.. it was found that the cooling nozzle for that cylinder was partially clogged with a piece of o-ring. They had used brand new cooling nozzles.. so the piece of mysterious o-ring was already in the engine block and found its way to the cooling nozzle and starved the piston of oil.. and a lot of destruction to the liner, piston, etc. followed.
so.. Check the cooling nozzle. See if it is blocked up, or had gotten bent and was not cooling the piston properly.
ref: http://rawze.com/forums/showthread.php?t...2#pid22182
and...
ref: http://rawze.com/forums/showthread.php?t...6#pid11446


case#2: I warn people quite often about this ... and it also used to say this in the old manuals ... TO NOT TO USE THE ENGINE BRAKE ON ITS HIGHEST STAGE FOR THE FIRST 50,000 miles after a rebuild!. - I have seen people loose their engines just like you described there right after an inframe if they use the jake-brake on high., The valves are tight and need to wear in.. and for the first 50,000 miles or so, a valve can have just enough closing delay in it during high engine braking to strike a piston and destroy the cylinder.

Matter of fact, forum member Unilevers found this out the hard way once. He built the engine right.. and then took it in a test drive with a heavy load behind it to break it in .. and it destroyed the engine when it got hot and the jake kicked in .. and it on its highest setting. I think he said it t wasn't 20 miles down the road. It destroyed a piston/liner as well.


So if I had to guess it ... I would say case#2 maybe?.
- You did say that you were hauling 140k load. I bet that engine got nice and hot like it should, and likely the jake setting on high in the dash?. A no-no in the first 50k miles on a fresh rebuild that is not broke in yet.

What makes this problem far worse is many people are h#ell bent on setting that jake-brake delay to zero so that their engine can 'bark' between gears. This makes/amplifies this problem greatly, and is very hard on the engine otherwise any ways.

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And when someone uses non-OEM parts.. you can see where tighter than normal valves, maybe wrong clearance on a wrist pin, etc.etc. can be a serious issue. A lot of problems has been seen with improper clearances on non OEM parts on these engines.

It is a mechanical device. It does not just 'feel' like blowing itself apart ... so something somewhere got missed or was out of spec.

If all oem parts were in fact used.. and you can see where it was a defect in one of those parts that caused the failure .. then there is a one-year warranty that will cover it. This unless you used parts that do not belong to that ser# engine. i.e.> someone putting parts on the engine to 'uprate the hp rating' will not get any warranty coverage.