Engine Overhaul

Robert Szego

Robert Szego

New member
Sparky, my 1973 7GCAA has accumulated 2,500 SMOH. O/H cylinders about 75 hrs. ago.

On the last flight, I noticed an unusual feel to the engine something like internal drag and some hesitation when throttling back for landing. Alll indications were normal: EGT, CHT, RPM. My A&P/IA looked it over, borescoped the cylinders, etc. and found nothing off. He wants to run the engine for any untoward indications, but it's been too cold to start it safely.

At this point I am pretty convinced that only a Major will allay my concerns. Contacted Penn Yan who responded quickly with a good estimate (not cheap!) They offer several options including upgrade to 160 hp at no additional cost; they offer top options including o/h steel, o/h nickel or new Lycoming cylinders (which I assume are steel) Am leaning toward the nickel option on the assumption it keeps better when not flown a while. Included is shipping both ways.

Tried to get a quote from Lycoming, but Aircraft Spruce who is the current dealer kept asking for more and more data until I had enough. I know that they will accept the core regardless of condition, but at (I guess) a much higher cost. I was told they will not update to the newer -B2B of 160 hp.

Choices, choices. Any experienced comments are appreciated.

Thanks,
 
Robert, A few thoughts for this big decision.
1. Try another Lycoming dealer, Air Power 877-278-2210 see if they can help without a big hassle.
3. The Aviation Consumer, (aviation consumer.com) did a report March 2018 on "Overhaul Shop Survey". Zephyr Aircraft Engines came out #1 on overall satisfaction and warranty rating. Penn Yan was also very good, in the top 5.
4. They did a Cylinder survey April 2012, Lycoming cylinders came out on top for Cylinders in that survey. By the way all Lycoming cylinders are nitided steel. They are what I would use.
5. March 2010 they did a survey on engine shop long term support, again Zephyr Aircraft Engines came out on top, with Penn Yan also very high.
On the other hand I have a friend with over 3200 hours on his Decathlon engine and has no issues. It might be a good idea to run the engine or take a short flight around the airport to warm the oil and then examine the oil filter and send in an oil sample to see if it's making metal, especially since it had cylinders off 75 hours ago. It is possible a main bearing was deturbed when the through bolts were loose. If there is significant metal there is no question, it needs overhaul.
Good luck and keep us informed on how all this goes for you.
Bill B
 
One more factor I forgot to mention is that having the overhaul shop near your home base is a big plus for that shop, especially for warranty work. :D
Bill B
 
I had my engine overhauled by Don George Aircraft in Orlando, Fl. I had issues with oil leaking past the valve guides in new lycoming cylinders. Don George Aircraft took care of me with no arguments, I highly recommend them. I'm not impressed with the quality control on new lycoming cylinders however....Robert.
 
Yes. I am having Penn Yan do the overhaul, adding 10 hp in the process. Progress is painfully slow, as my IA has not been able to start pulling the engine (he is quite good and alternatives are far too few and pale in comparison.) He flies a 777 internationally, so is hard to pin down; he'll get to it soon. Penn Yan has quoted 60 day turn-around, so attendance at Sun 'n Fun is in jeopardy. Pick-up and delivery is included.

Opted for nickel o/h cylinders. New Lycomings are not that much more, but are not nickel plated; Having followed overhaul shops for years, I believe Penn Yan gives better results than Lycoming.

Another thing: I am considering adding the JPI EDM700-4C and wondering if the 2-1/2" is easily readable or do I spend another $349 for the 3-1/4" version. Other options under consideration are oil pressure, oil temperature, OAT, rpm. Trying not to overspend and wondering how useful these items are.

Thanks,
 
In my opinion, if you have space in the panel I would spend the extra $ for the 3 1/4" version.
 
Robert,
On the JPI, definitely go for the larger face. I had the smaller instrument and found it hard to read without really focusing on it.
I ended up pulling it and having them swap it out for the larger face which was a headache.

-Adam
 
I’m a little late to the forum, but have a few things to offer for anyone else facing The Big Overhaul Decision. Not necessarily specific to your engine situation Robert, but in general:

I was faced with the decision a few years ago, and with little knowledge/mx background, went simply off the recommendations of my A&P to overhaul the AEIO-360 on my 8KCAB after some metal was found in the oil screen during annual. The engine was about 200 hrs short of TBO, but “close enough,” and “all signs” were there that The Big O was mandatory.

I would consider myself more mechanically-inclined than not, but without any knowledge of my powerplant (at the time), was at the mercy of the repair station. To their credit, they were simply making their recommendation on the basic facts, “metal=overhaul.” Looking back, I wish I would have made a greater effort to make an informed decision and troubleshoot-what kind of metal was it? Was a valve going bad, or something more serious? Has this been happening long-can we clean the screen, fly 20 more hrs, and re-inspect? It could have been a simple cylinder replacement versus an entire engine tear down, but I’ll never know. I’m not an A&P, but I could have been much more discerning and possibly saved myself thousands of dollars.

I recently bought Mike Busch’s “Engines” book, and wish it had been published a few years earlier. It opens with how engines work, are built, and leads in to health-assessing, maintenance, and troubleshooting. I think it’s a must-read for any owner/pilot. He’s also a huge proponent of engine monitors, and I’m considering a JPI unit installation myself.

-Nick
 
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