How do you know when it's time for an inframe?

Over a gallon of oil ever time you get fuel or something bad happens.
Three things I feel can help prevent something bad from happening are: Replacing rod and main bearings at engines half life on estimated overhaul. Adjusting valves and injectors at least every 250,000 miles. Maintaining cooling system and regular oil changes.
A lot of contravesy around here on when to do those things and some good posts on oil samples. Use search block on top right and I thank cowpie posted some good oil sample stuff.

 

Learn to work on it yourself. No expensive tools required and a 12.7 is stupid easy. For what is worth, i rebuilt mine at just over a million and it was immaculate inside. The cross hatches were still in the liners. Bearings had almost no wear. Could have probably gone another 500k with no problem, but once ya got it apart is stupid not to just do it. The parts are cheap.

 

Funny,back in the old days,lol.....In the 70's and 80's,we used to get around 400k on an inframe,NTC Cummins.First 100k miles,no oil use to speak of.200k miles on the overhaul,a gallon of oil,every 5,6k miles or so.At 300k miles on overhaul, a gallon of oil every 3k miles,and by the time you'd get to 400k miles on your overhaul,pretty much a gallon of oil every time you fuel.Time for inframe.But,I could inframe it on a weekend myself,and do it for less than $2,000. 3 heads x $200.,sleeve-piston kits,$600.,bearings $200.,injectors$30.x6,+oil,filters,and gaskets.
Technology,oil and materials have come a long way.

 

With oil sampleing you can tell tons of whats goin on inside that engine..You can tell if bearings are startin to go,streaming injectors(fuel dilution)coolant in the oil ect ect....Just dont do oil testing from truck stop bench top testers..Do it with http://polarislabs.com/ They spend millions on required gear and maintenance/upgrades to give you some of the most detail and accurate results.....Hell send them your urine sample and they can tell you what you ate for luck and what time you had it..

 

Just do a valve set and run it..
If no oil usage and blowby is normal,getting good fuel mpg then you have nothing to worry about. Sounds very healthy to me.

 

If you're a licensed aircraft mechanic,you won't have any problems.Just study up on the technical specs,and be on the lookout for a 3/4 drive torque wrench.Before I built my shop,I used to overhaul mine in my driveway.Wouldn't waste time on a leakdown test if your not using oil,or blowby issues,your oil analyis will tell you what you need to know.Also,I wouldn't necessarily count on the dealer knocking it out any quicker,unless they promise it,and make good on it.