Crosshatch Damage

ChristopherH · January 13, 2010

I just had an opinion question for everybody about this 6.0 I'm working on right now. It had a cylinder #3 injector failure with hydrolock that was repaired at another dealer. I have it now with only 200 miles since that repair--cylinder #3 had a dead misfire and showed a major loss of compression on ids. Manual compression test backed up that it had 0 psi. No problems were found with the valve train, so off comes the cylinder head. One of the #3 exhaust valves is burned away right at the edge (damage is approx 1/4" in diameter) valve

seat is damaged, and the glow plug tip is melted slightly. The piston does not appear distorted in any way, and the cross hatching looks good (engine only has 46k on it) however, there are several vertical marks in the cylinder--especially adjacent to where the burned valve was. I don't want to use the word scratch, because they have no metal transfer in them and will not catch a fingernail. Cylinder #1 has the same type of marking, but not as extensive. I have seen marking like this before on other 6.0s that I have taken apart for head gaskets or other reasons and nothing was done about those (they were under warranty and thats what management decided) These did not return with any concerns. Obviously, these marks have to be due to either debris that was trapped between the cylinder wall and piston, or the piston itself contacting the cylinder wall due to deformation or missing skirt coating.

The hotline said: "Anytime there is a melted piston, metal transfer, or distortion of the cylinder wall/crosshatch, short block replacement is recommended."

My question then, is how bad is too bad? Is there zero tolerance for what you would consider usable or not usable? This truck is a 2003 (out of warranty), and the customer doesn't think the cylinder looks too bad--but he doesn't want to pay a bunch of money to re-assemble an engine that is going to fail again soon because of an incomplete repair. I would normally tend to err on the side of caution in this situation, but I welcome everybody elses opinion on this one.

I will try to post some pictures tomorrow as soon as I get my good digital camera from my house. Thanks.

Aaron · January 13, 2010

I think you perhaps answered your own question with the "shit between the piston and cylinder wall" idea.

If you can't catch your fingernail on it, I'd maybe try running a hone through it and see if it clears up. If so, I'd put some rings or a piston in it if required and call it a day. Do you have the piston out? Maybe there's a little ratty part on the piston but you would think if that was the case, the marks would be more towards the center, than the top, just from the thrust wear of the piston changing direction. (I'm assuming it's at the top since you said adjacent to.)

I would measure the piston, also, especially in the area where the wear/marks are.

Sounds like you've got a head scratcher (no pun intended).

dieseldoc · January 13, 2010

I am not a fan of spending unnecessary money. But it seems to me the customer has sort of answered your question as well. For peace of mind to both of you, you may want to consider the short block and a head. At this point he has warranty on the bottom end and head, as well as it cant bite you in the ass 3 months from now.

However at the same token, if you cant catch a nail on it and it is not a large area..... you could probably get away with assembling and may never see the truck for a problem with this again. The key here is to find out what the root cause of the mark is. In the event that what is causing the marking is still there or an issue, that is going to make the marking worse. Pictures are worth a thousand words in situations like this. My prefference in this type of situation is to make a reccomendation of the repair that has the least chance of failure(short block replacement, and head). Than let the customer decide. Always be sure to note that the customer made this choice in your service report, and be sure to date it and put a time on it.

I always want to do the best thing for my customer and give them best repair that I can without completely emptying there wallet. But you have to look out for your best interest as well. If the patch doesnt work out he will tell everyone he knows how the dealership couldnt fix his truck. if it works odds are he will tell no one that you saved him money and fixed his truck well.

LARRY BRUDZYNSKI · January 13, 2010

Vertical marks on the cylinder wall tells me to inspect further....Possibly bent rod and piston scuffed the wall from hydrolocking. Have you pulled it down any further than pulling the head? Maybe a small piece of the injector tip or valve from the prior failure? Cylinder is dead, Why? I think you need more tear down for this one. Before I just put a head on it I would look deeper. I understand that it's out of warranty, but remember you're putting your name on this repair. CYA...... Posted Image

ChristopherH · January 15, 2010

This customer has an aftermarket warranty, and after their adjuster came out the other day and inspected it, I think they are going to send us a used engine to install (typical of these am warranty companies) When I get the engine out, I will pull the piston to inspect it closer, but here are the pics I promised--sorry if they are not very clear, but the vertical marking is hard to see.

Posted Image

Mikill · January 16, 2010

I have seen a couple of 6.0's with the same vertical markings but never really thought anything of them because there was no deep scratches or loss of compression. Reassembled and everything turned out fine and no concerns ever found from those markings.

ChristopherH · January 18, 2010

I agree, I have done several with markings like this and had no problems--I just wanted to see if you guys had seen these same marks and how everyone else is adressing them. This particular truck I told them that repairing/replacing the rh cylinder head and reassembly would probably fix it just fine--BUT based on those marks I was't going to gaurantee it. The recommendation to replace the head and short block came from management--they do not want to take any chances--would rather not fix it if there is any room for this to come back on us. I can't say that I blame them, but if it was mine, I would fix that head and reassemble it.