I pulled the #6 piston out of my 03 because I suspected a bad wrist pin. After I got the piston out I noticed that the piston skirt on one side is scored pretty bad. But the other side doesn't even have a scratch on it.
Another thing. My engine rebuilder says that since I am on a tight budget that he would not worry about putting new rings on. He says we can re use the rings on the next piston too. Is this a good idea or should I save and get new rings. He thinks if we are gonna do the rings we should rebuild the whole engine. In other words he is saying all or none.

 

IMHO I would be very suspect of a piston that has been scarred as bad as you describe. There may be metal fatigue and it may have a small crack that will show it's ugly head later. While it is apart, do it right and save yourself the grief later.

 

Are you just going to do that one hole? I would do rings for sure and hone the block.

 

I am definately replacing the piston.But my guy tells me that's the ONLY thing he would replace unless we are doin a FULL rebuild which at this time we are definately NOT since I work in construction and right now have zip for jobs.

 

You can skimp by but that may cost you later. I would a least do a set of rings on that one piston if you can. Any scoring on the cylinder wall of this cylinder or others. If no then use the old rings. You may still have some blowby, may not.

 

cylinders 1 thru 4 look perfect. #5 has 1 score directly vertical and it's smooth. Can feel it with finger, but NOT with your nail. Must have been in it's early life. Number 6 has some scoring down low from the skirt. I am gonna price the rings and see if I can squeek them into the budget. I won't even tell the rebuilder. No need to hurt his feelings by ignoring his advice since He is probably gonna get me the piston at his cost and charge me next to nothin to put the new piston on the rod.

 

Definately put in new rings! The amount you save by re-using the old ones is very little. Also the old ones will have to break in again because they will be in a new position, then they'll be worn worse than the other ones. You should hone that cylinder anyway to help with the breakin and to get rid of any scoring damage. Replace them.

John

 

Yeah I think I agree. Gonna use new rings. Should I hone all 6 or just 5 and 6 ?

 

If you are not gonna take the other five out then, of course, no honing. If you do pull the other five then hone and replace those rings too. Doing them all is the best thing, then all have new rings and all pistons have been inspected.

Do your absolute best to keep it clean! No grit down on the crank!


John

 

Very light hone on 1 - 5. Can even use scotch pad (the green pad) just to clean glaze off wall. Lightly hone # 6 to get smooth where score is. It may make some noise but should live. Make sure Cooling oil squiters are clear and not bent. Lack of cooling lube is good cause for scoring. Heat from too much power is another reason. Cummins build engines to handle stock HP. More HP gets different cooling solutions from Cummins. Remember white glove test.

 

I would never put rings in without straighting the cylinders. If you put rings into a motor and the walls are not straight it can cause the rings to break. Least on gas engines, seen it lots of times. Plus if you rering it then hone it to spec. Rings dont seat well on slick walls. If I was that far into the engine I would have it honed as long the walls straighten out fast you wont need to bore it. Then you can use same pistons, clean the stress relieve the rods and check the crank. New bearings and rings and your gtg. That is a overhaul, just putting new rings in wont help you unless u do the hone.

Ask him to check the cylenders and see how far out of spec they are, if he thinks they can clean up fast do it, hone, rings, bearings, happy engine.

 

Why are you running two threads at same time?

 

Cause he's anxious! Its