Detroit pistons (5&6)

If your near a million miles I would do the rebuild. Your going to be tearing down the motor anyways.

 

What he said, it will only cost you basically the cost of the other four holes with the extra labor being minimal.

 

With close to a million miles I'm sure the head isn't as good as it may appear. I would put a reman on it now and save that labor later

 

I understand your want and need to save money. We all are in that boat. Engine tolerances are down to the .001 sometimes .0001 and labor to go into once or a dozen times is almost the same. I suggest that you take this truck to an independent mechanic with a dang good reputation tell him your situation and get an estimate. Listen to his recommendation. We cannot see inside this engine and there is no way of knowing the damage with teardown and proper inspection of all parts of the effected cylinders. I have overhauled more engines than I can count. I can count on one hand the times I coulda just put rings in a hole.

 

The detroit 14 liter has rods larger than the liners. The pistons have to go out the bottom so the liners have to be pulled to put rings in or the engine would have to be pulled so the crank comes out first. Either case, no mechanic that know what he's doing, wouldn't attempt rings without doing a complete inframe rebuild.
I say this with experience as I rebuilt my 14 liter 3 years ago and couldn't believe the pistons wouldn't come out the top. Only engine I've ever come across this way.

 

How many mile's are on the motor , and how much oil are you using

 

That's alot of oil. More than ring blowby. You might have a broken rimg