Q: I am purchasing a 1969 Piper PA-32-300 that has 1,814 hours. Should one always rebuild at 2,000 hours? Does this require new pistons and/or cylinders, or does re-honing and new rings fit that need? Any benefit of following with oil samples at changes to get more life from the engine? With your experience I would like your thoughts.
A: Your question “should one always rebuild at 2,000 hours” is a little difficult to answer. I could take the easy way out and tell you that, in accordance with Lycoming Service Instruction 1009AW, the recommended Time Between Overhaul Periods is 2,000 hours.
However, that’s only a recommendation and there are many factors that need to be considered before you can make a decision about your particular engine.
First of all, I’m concerned about the total time versus calendar time. If I did my math correctly, this engine has been operated approximately 38 hours, on average per year, during the 47 calendar years of its life.
That leads me to believe this engine has suffered several periods of extended inactivity, which is detrimental to the engine from the standpoint of internal corrosion taking place. Conducting a thorough borescope inspection of all cylinders would be highly recommended to look for signs of corrosion.
I would also recommend you do a very close review of the engine logbooks, paying particular attention to the oil and filter change frequency compared to the actual flying and calendar time.
Also do a close review of the logbooks for general maintenance that has been performed over the life of the engine, such as hot differential compression checks, etc. What is and has been the typical oil consumption between oil changes?
My biggest concern regarding this aircraft, as I mentioned earlier, is its age. I would take into consideration when making an offer on this aircraft that you will soon be required to take some type of action regarding the engine.
You have several choices, of course, including a field overhaul where the cylinders could possibly be reworked depending on their condition.
I suggest you obtain a copy of Lycoming Service Bulletin 240W, which covers “Mandatory Parts Replacement at Overhaul and During Repair or Maintenance.
You may also want to consider a factory “rebuilt” exchange engine, which would provide you with a “Zero Time” new logbook, but before you go that route, please check your options with a Lycoming distributor because there may be some restrictions due to the age of your engine.
There is no doubt money becomes a big issue in making any decision here.
Let me step back just a bit and respond to your question regarding oil analysis.
If oil analysis has been a routine at every oil change on this engine, then it can be a powerful tool when it comes to assessing the health of the engine. However, if you are asking if beginning oil analysis at this point in the engine’s life is a good idea, my answer would be maybe.
If the aircraft is put into service and oil analysis is going to be considered, it should be done over a period of several oil and filter changes. One oil analysis sample doesn’t tell us anything, really, because we have nothing to compare it with.
Just as a suggestion, I’d consider doing an oil and filter change now, then the next one in about 10 hours, followed by another in 10 hours. This should give us a pretty good baseline to make our comparisons.
If the first sample shows, for example, high iron content and possibly high aluminum content, I’d be thinking we have severe corrosion in the cylinders, which probably is a result of the extended periods of activity. It could also be an indication of camshaft and tappet wear caused by corrosion.
I don’t want to discourage you from purchasing this aircraft, but I want you to know what the risks are before you put any money on the line.
Honestly speaking, you should be prepared to spend some money on the engine in the very near future.
I wish you the best and urge you to proceed with caution.