engine problem

[scarecrow]

has anyone ever seen this happen to a piston before the crown of the piston just seemed to disintegrate into tiny pieces and there doesn't seem to me any reason for it. as there is very little ware on the sleeve


any idea what might have caused it or is it in once off there are some scratches on the sleeve now so it will need to be honed before replacing the piston

 

[grandads_shed]

over heating around the cylinder ? not enough to sieze it but hot enough to make it go brittle and break up .. they are alloy

 

[Emmsy]

just the piston or has the head got damage aswell?

 

[julieanncharters]

depends on engine type diesel or petrol turbo non turbo.
running weak mixture on one cylinder could cause yer damage .
could cause over heating and pitting
would need seperate injection for each pot for that to happen if only one piston is affected.
was it running like a pig for a while before the strip down?
hard to tell from yer photo.
is it melted or just a build up of carbon on the piston crown.
excess oil burning in one cylinder might cause this.
could be oil way crack /head gasket or possible stem seal on valves passing oil in.
you mentioned scratches on liner might be passing oil to give same prob.
give that crud on the top a good scrape it will be rock hard but should come away if carbon.
it looks to have built up to the shape of the port in the head which makes me think you have burning oil probs.
happy hunting

 

[grandads_shed]

come to think about it ,, it could happen if the fuel/air mixture getting to that cylinder could be wrong ,,, i have had it happen many years ago on one of my bikes

 

[alogaparaloga]

Can you get a better photo of the damaged piston?

I suppose from the piston bowl that the engine is diesel.
If this sort of damage was on petrol engine I would say it's clearly because of knock (pre-ignition).
In the case of a diesel, in order to have pre-ignition the injection should be off on one cylinder to cause excess heat on top land.

Another scenario could be an overheated piston due to bad oil cooling. It happens when oil squirter fails and the heat has nowhere to go.
Inspect the oil lines in the crankcase and take photos of the piston and cylinder.

 

[scarecrow]

its a 3 cylinder diesel off an old ford digger the head and valves look okay it is not melted just shattered seems to have come away just above of the top ring
she doesn't do a lot and I don't remember her ever overheating there was a problem with her injection pump last summer it was replaced with a reconditioned one
it happened while starting her on Christmas morning it was about -10 but she had heater under her for two hours before starting she did start but then sounded rough and cut out its it just happened suddenly as they wont run onto cylinders until then she had been running fine
is there anyway to check if the injector pump is putting in the right mixture

 

[Tomlt]

Any signs of water in the cylinder/fluids when stripped? Could be a hydraulic shock failure from a blown head gasket?

If it was a Perkins I might have more of an idea (plus I could get the lads at work to take a look )

 

[scarecrow]

try and get a few more pictures tomorrow as it took most of today to get the sump off as you have a move the front axle and housing forward about three or 4 in. not a nice job

 

[alogaparaloga]

You need 3 volumetric tubes to collect fuel from injectors. not that easy. the other option is to fit a pressure gauge in each injector feed and wach for any pressure variation.

For sure there is a damaged part some where around. the piston is just the affected part.

Such damage is difficult to happen at startup. You have to think what may happened the last time it was working.

 

[oilcooled :)]

do you use easy start?

 

[scarecrow]

there was some water in diesel filter could that have caused problem he had been started the previous day just to move her out of the way and she was running fine
here's a picture of the head gasket which looks okay to me but they are prone to go on 3cylinder engines

 

[Westerngeophysical772]

That looks like theres been a foreign object in the cylinder and its been wacking away between the top of the piston and the head leaving the soft piston crown damaged but the hard steel head clean, that would explain the untouched combustion chamber in the piston too as its lower and out of reach, there are also some curious "ARC" shapes stamped into the piston head, they remind me of large bits of broken piston rings. It all makes me wonder if this engine has been damaged by a previous owner unknown to you, and its been running like that for years until your strip has revealed it. I would expect to find marks on the head from this damage altho not as bad as the piston.

 

[knoba]

Cracked crank?

Hard to tell without being there.

 

[squazy84]

water down the exhaust? corrosion on any valve seats?

 

[pedrobedro]

Burnt valve used to look like that, like the top of the piston had been shot peened. Have you had the valve out and checked it as you might not see the damage when it's shut. The bottom of the top picture looks suspect like the watercourse has been breached possibly across to the cylinder.

 

[scarecrow]

that bit of the head gasket looks a bit dodgy and is right beside then cylinder there is also a little rubber ring built into then gasket around the water port which looks to be okay but hard to tell
got the piston out and the bit that I thought was a ring seems to be part of the crown.
is the crown attached to the top of the piston and could it have come lose
here's a few more pictures



these are the bits that looked like rings but they are aluminum


there are some marks on the head not surprisingly i well check the valves tomorrow some of that stuff must have gone to the exhaust one

 

[pidgeon chit welder]

big end , little end bearing prob perhaps allows piston head to slap the cylhead also con rod bolt prob allowing the same sort of thing ..you would have had a hell of a knocking noise.

If " repaired " by a previous owner from any of the above states and the piston etc not replaced it is not surprising the prob has developed .

 

[carbon]

If its a ford engine without liners these were prone to the blocks becoming porous and the water ending up in the sump. It could be possible that some water has got into the cylinder and caused the damaged. I also assume that it has a rotary injection pump and the quantity of fuel injected should be the same for each cylinder.

 

[scarecrow]

its a ford engine without liners sleeves look fine wit no lip better than I thought they would-be there was no knocking previously whatever happened seemed to happen suddenly just after start-up so i am thinking water could be a problem as i cant see anything wrong in the sump
but I will get a mechanic to have a look before I put it back together