Got my motor changed out last weekend, this is what I found in the bad cylinder. What could have caused this? If it is something I could have prevented I don't want to do it to the new motor. I was at around 305,000 miles on all original injectors ect. when I started having problems. Could a bad injector do this? It was the number 5 cylinder.

 

I have no clue....
Was the oil squirter nozzle still in place on this cylinder?

 

I've got two cores with the same #5 damage. Welcome to the club.

 

Is that porosity on the cylinder wall? As in cavitation?

 

All the oil squirt were in place, and no that was just some oil and dirt on the cylinder wall.

 

I know one thing, it sure is good to be running on 8 cylinders again, forgot what a good motor was like!

 

First off that piston has been over heated. Discolour on the pin area and melt on the rim. The damage on the cylinder is caused by mis detonation. Saw the same stuff when I blew my motor, and took it to the machinist that did my bore, and he confirmed misdetonation and overheat. Heat, unless you bagged on it, was probably caused by a bad injector. He recommended I replace that injector. Mis detonation also usually a bad injector brought to high rpm, then bad injection and detonation usually early causing piston to slam against wall. Cant tell by your picture, but the top ring usually breaks. That was the machinists opinion. After the level of expertise he put into my block, I tend to believe him. I think you will find the cylinder is fine, and the scuff is actually piston aluminum on the cylinder. Can be cleaned and honed or bored no problem. Good luck.

 

Thanks Absolute, thats good info. That top ring was broke and that is a very deep gouge in that cylinder. If anyone uses that motor it will probably have to be sleeved.

I went with new AC stock 160 injectors in the new motor. I've had it running a couple of days now and like what I'm seeing so far, can't wait to get the 5th wheel out in a month or so and see how it pulls now. I ended up finding a 2000 model motor with forged rods at a local machine shop that someone had all the work done and never came back to pick it up.

I give Clay at RiffRaff and Joey at Terminator a big thank you for all the help on getting me parts.

 

I am in total agreement with absolute. heat at the crown/top of the piston is the #1 cause of piston cracking, piston ring failure ect. This is why everyone goes to such great ends for pyro/temp gauges on the EX. Everyone knows heat is the enemy. I am certain that would clean up on a over bore. Weather it will on a hone well I know the hyper pistons like to expand ALOT more and have to hone more room to fit. Slight chance it may work out. Depending on the Silicone content. IE what the MFG wants for a side number and what kind of wear you have. Just as a shade tree no measuring device check is if it catches your finger nail on that ring ridge your most likely going to have to bore. Granted your not using a tool but its a good guess without one.

And from my evil eye Ok eagle eye you were good all the way around till that one spot you have carbon. go check with your nail

 

Cylinder looks washed too. I would say bad injector and lack of lubrication on the cylinder wall. Carbon build up can add to that problem as well. Was it idled for long periods or go long on oil changes? It's all just my theory, it reminds me on a lighter scale of a few blown track motors I've seen.

 

The populace has spawned a new word (google'd it too) that doesn't exist except in Al Gore's internet.......