They look pretty light, but it's hard to tell by just a picture.

 

you got me confused, did you mean replace that piston with the engine still in?

as far as the cylinder goes, leave it alone. those little cuts (from pictures) don't look deep enough to do anything. you'll likely do more harm than good doing a bottle brush hone job on a modern engine.

 

I'm with the 'doggy, I'll bet the original owner put nothing other than 87 octane gas in it the whole time he had it. I wonder how many of the "but the manual only recommends 89 octane, says you can use 87" guys will notice this problem at some time...

 

Unless you can prove beyond a doubt that's what caused it, probably not at all.

 

87 octane detonation or retard caused that.... man that's hard to believe, for me anyway. Looks like a large chunk of metal got loose somewhere, piston ring maybe. At least that is usually what causes it on the large natural gas motors I work on.

 

Man if thats all you got then I would hone out all the bores and re-piston #8 and #1 and balance the rotation assembly and put that biotch back together and run it.

 

That is clear cut sign of detonation. Not many guys know the real danger involved.
If it were from metal chunks, where did they come from? if you say the piston itself, there's no real chunks missing and the only way to get the piston to even chunk or break off is from detonation.


To the OP, i would get the Vin# of the truck the engine went to and pony up for a carfax and check the mileage and salvage report out. Worth the $15. And if they say they don't have the vin, they are either lying or they aren't that big of a company, because i think by law they have to keep records where the engine came from due to the overwheming theft of car parts going on these days.

I wouldn't just leave that cylinder as-is, and no you can't sleeve it in the bay. You need to pull it and send it out. i wouldn't spend my time or money just putting new stuff into it and leaving it as is unless the scratches are so superficial(doubtful). When i say superficial I mean tha the honing markes are still present going through the scratches. if you lose the hone mark, then they are generally too deep.

 

I say leave it alone if you'd rather not mess with it, dog says do it right and send it out. at least he and I are agreeing on something: do not, for ANY reason, just take a bottle brush 'hone' to that cylinder.

You're looking for something that runs and runs reliably. Those scratches in the bore aren't going to compromise a reliable ride. Swap the piston and rings, they'll seat.

87 octane didn't cause that mess, my money is on a head gasket and coolant getting in there. The clearance from the OD of the piston to the ID of the cylinder is too small for a chunk of piston ring to get up there, so a piston ring didn't cause that damage. I'd like to get my hands on some of those piston rings to check them out.

 

if you hone the scratches out, you will need oversized rings, if you leave the scratches in, you will have gas by passing the rings and end up with blow by, of the gooey crap you pulled out of the filter from the bypass tube. The best thing to do with that engine, is replace it with a junkyard engine, or do a complete rebuild. Remove the block, bore all 8 holes and replace the pistons. Dollar wise, it is about the same either way, but you will, in essence, have a much better engine with rebuilding, but replacing is faster and less work. your choice.

 

I mistyped - I meant to ask if it is possible to replace the piston with the engine still in place.


If a chunk of metal got loose, wouldn't there be more damage to the valves from it coming in or going out? The valves all look good. Also, I did not find anything in the cylinder, and I doubt something that could cause this damage would have been incinerated.


By bottle brush do you mean something like this?




I think that is my next plan of action. I will drop the pan and see if I can get the piston out before I decide ultimately what to do.


Here are some more pictures of the damage.

Passenger side - Cylinder 8 there on the right is pictured in the previous pictures. It has the worst damage.





Driver's side - Cylinder 7 on the left has the next worse damage. Though the damage is not as deep.





Cylinder 5 Close-Up





Cylinders 1 and 3 are not nearly as bad.





The valves all look good, but there is a little side damage on most of the cylinders.