i own a repair shop and i've got a customer that DROVE in a 2003 dodge ram 1500 4.7 liter

misfire
check engine lght
smoke out of exhaust

tore down engine:

found hole in piston: appears to be burnt

light detection of head gasket leak
heads warped slightly

warranty company needs to know source of failure, i have not been able to find out why it has a hole in the piston

E3 SPARK PLUGS e3.48

no indication of any valves hitting the piston

alot of stuff melted on the head& piston

ANY SUGGESTIONS?

 

Picture

 

Well my bet is he has had a head gasket leak for awhile which reduced compression enough in that cylinder or possibly got coolant into the oil system causing bearing failure, and under a heavy load (WOT) the truck likely knocked very badly (I would expect the driver to recall a very violent jerk)

But a knock that would have broken a piston would have likely put a hole on the outside of the piston not in the center. Only other time I've seen a piston have a hole in the center of it is when something collides with it.... If the driver is handy I'd assume he might have put a new plug in to try and fix it himself...

Which leads me to believe that it is either a spun bearing caused by headgasket leak or possible may have been a faulty piston and/or wrist-pin...

To tell I'd need to see the piston, rod & the bearings to tell what happened.

So get to work and take that piston out of there...

In short here are your likely events:

1) Head-Gasket Leak + Spun Bearing + Knock = Collision w/ spark plug.

2) Timing System Failure causing piston to collide w/ plug (very rare and would take a lot to cover up)

3) Defective Piston/Wrist-pin

4) MAJOR MAJOR Knock

 

Consistent use of wrong octane fuel.
Burnt and then dropped spark plug??
Al.

 

its a 3.7L V6 so unless the owner was using Diesel fuel higher octane wouldn't do that...

 

a failed injector can do that by leaning a hot engine... that will burn a pretty hole in a piston..

 

these are all excellant answers:

the plug has no signs of contact with the piston, and doesnt look like it was changed to cover it up....the plug is also melted

the injectors were also ohmed out and are all consistant with the same ohms, so i dont think we have a bad injector



this looks like a lean condition to me, but where did the lean condition come from....again it is only on one cylinder, so it has to be focused problem...like you said ( failed injector).....intake o-ring?....but these componets look all good

next?

 

look to see if the injector is clogged, then.. pull the tiny basket off and give it a look see..

i would say it is definitely a lean burned hole, as it is where the face is most likely to be compromised by such...

check the rail too, to make sure the gas supply is available to it..

 

Injector resistance will not tell you if it is clogged.

You must either do what Drew said above or have it flow tested...

I've personally never seen a hole like that in the center of the piston but it might be possible...

 

injector looks fine, not clogged

how do you test it correctly for flow ,

keep in mind this engine is torn apart completley