engine failure

i once worked with a guy who would fire up his brand new pete dump truck. and IMMEDIATELY kick up the cruise. then went back into the shop for a cup of coffee and to chat with the boss and everyone else. after a year, it started to sound like a timing chain rattling against the case.

when he finally got canned. the next guy to drive the truck. NEVER turned off the PTO. he'd come out and fire up the truck. once the air was built up enough you could hear a combination of screeching and grinding from the PTO trying to engage.

 

cat guru's??? i'm all out of idea's.

 

You need to look at the underside of the pistons to see if they are black and blue. If so then you either have one of three problems

lack of oil from the cooling jets

too much fuel

not enough air

 

I guess from reading the above it was all 6 Pistons so the chances of all 6 Piston squirter's blocking is out of the list of reasons.
Again it couldn't be all six with bad Injector Tips failing at one time.

However the Head is Cracked in 3 places you mentioned!!! Usually seen after High engine temps.

The piston crowns look to be well patterned and clean with no sign of bad nozzles.

Did u do an Oil sample? I would be looking for Fuel Dilution and Oxidisation and then have another think about Why it failed.

Smacks of Heat!!
What about the Big end & Main Bearings? This may tell us if the heat was localised around the liners or in the oil as well.

 

The one-piece (Monotherm) forged steel, low-friction piston is used on ACERT C15 engines. This low-friction piston has a special phosphate coating on the surface of the piston body (including the ring grooves and pin bore) which prevents scuffing of the cylinder liner.
Oil-related piston failure is most commonly caused by the abrasive action of contaminated oil which results in wear of the piston skirt. Indications include a very dull gray piston skirt, chrome facings worn off on all rings; oil ring rails worn away, badly worn grooves and some liner wear. Piston scuffing, which appears in streaks on the skirt, particularly in the pin bore area, and little or no scuffing on the first land, may be caused by inadequate liner lubrication. Breakdown of oil film can produce seizure marks.
Piston rings can show wear in the spring groove. Some spring groove wear is normal, but neglected oil changes will cause severe ring "lock-up" that occurs when the spring catches in a worn groove and prevents full expansion
Nitride coated piston rings along with the liner package are designed to provide superior oil control and reduce exhaust slobber during extended idling. The three piston rings are located in grooves in the crown of the piston. These rings seal combustion gases and provide oil control. The top ring has a barrel face keystone ring. The second ring has a square face. The oil ring is double railed, is profile ground and has a expander spring behind the oil rings to provide correct tension against the liner. Four drilled holes are used to drain excess oil from the piston oil ring groove to the interior of the piston.
In the lubrication system coolant contamination may deteriorate the rubber components within the oil filter(s) causing the filter element to collapse and allowing unfiltered oil to bypass into the engine. This plus the decrease in the oil lubricity can quickly lead to an increase in engine wear metals and damage.
Acids and other by-products of oxidation will thicken and darken lubricants and tend to cause early restriction of oil filter elements.
A percentage of fuel in the oil that is greater than 4 percent, is an indication of excessive fuel in oil dilution

Maybe some more info on the history of the engine and a time line of events would make it easier for people to help, you would know if there has been major heat issues causing this unless there are no gauges in the truck. can you post pictures off the head?

 

Are they aftermarket pistons or cat pistons? In my experience such a thing is not possible with genuine Caterpillar pistons


The acert piston can take a lot of abuse and still not look like that.it is very unusual.

I have had very similar failure with aftermarket IPD pistons

 

Any updated Trevor ? Have they come up with any failure analysis results for you ?

 

I have seen in the past that rolled liner o-rings can do that kind of damage. Piston cooling jets on all six of them being plugged or bent is hard to believe but is possible. Check for cracks around the piston cooling nozzles also. In the cylinder block check the bores for any sharp edges that may catch a liner o-ring when installing. When installing the o-rings make sure they go on square and true.... lube them up good and install... Doesn't hurt to lube the cylinder block bores as well..

Good luck!!