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Engine odyssey

Thanks for the update @aidanf123. Very interesting.

Pic upload should work. If you are using a phone or a tablet, make sure you enable the extra functionality in your profile.

Administrator
Shoreham EGKA, United Kingdom

That is great Aidanf123! Keep on reporting!

Antonio
LESB, Spain

So as a follow up to the engine odyssey, I got the fuel servo replaced, and the engine is working like a clock.
The Nicr cylinders ran in very quickly – I added about half a quart after the first 3 hour flight and since then the oil consumption has fallen off to very little(less than half a quart in the last 23 hours), I changed the oil and filter after 10 hours and it was clean.
The cylinders are very well balanced, after the first 10 hours I started running LOP and its very easy with the balanced temperatures – as you can see in the picture below the egts are within 20 degrees of each other (high cht temp on cylinder 3 is normal because the probe is under the spark plug on that one – JPI says its normal to see a 50 degree difference)
So all in all I would recommend the Continental prime cylinders for Lycoming engines, as for the other components time will tell.
Still cannot find a hanger in the Bordeaux area so I am SOL.

PIcture upload is not working – I will edit the post later on when I can get it finished

Last Edited by aidanf123 at 26 Aug 07:36

The people I can think of who are (or were) around there are @bordeaux_jim @jojo and @vrh.

Administrator
Shoreham EGKA, United Kingdom

I am thinking a blocked injector as well – not enough fuel getting to cylinder 4 – it will all get resolved this week.
Still have not been able to find a hangar in the Bordeaux area though, if I can’t find a hangar I am SOL

Sounds like a blocked injector. Perhaps contamination in the fuel line going to the cylinder? Or a duff spark plug, or even an internal magneto thing?

Administrator
Shoreham EGKA, United Kingdom

so I flew out last week to pick up the plane and the saga continues – the engine ran fine on the first flight (running it hard at low altitude for an hour) but the JPI 830 was reporting very high numbers (420-430 CHT on cylinder 3 and 4 – 1 and 2 were ok (my mechanic had previously run the plane on the ground for about 2 hours) on the second flight there was a small stumble on takeoff but a dose of boost did the job – still high temps on cylinders 3 and 4 -

Now the mechanic says that these JPI probes are not the best and are quite fragile ( cylinder 3 factory gauge was showing middle of the green when the JPI was telling me 430 F, and cylinder 4 egt was stuck around 1400 constantly irrespective of power settings)

So ok – I take off on a long flight across Germany(2 and half hours) – still at low altitude ~3500 feet and running the engine between 65 and 80% – I can see eventually that cylinder 3 actually breaks in I can see the temperature drop about 45F down to 370 (cylinder 1 and 2 were at 340), engine was running very smoothly though, so it seems that probe is ok – EGT on cylinder 4 is still stuck around 1400.

Land and fuel – half an hour later the engine starts up no trouble and idles no issue but if I try to run it up its vibrating all over the place and anything over 1700 RPM cylinder 4 EGT and CHT disappear like the cylinder is not firing at all, so I found a hanger and thankfully being france took a high speed train home(still took several hours longer than flying though)

My mechanic is gong to come out this week and look at it – good thing I am stubborn otherwise I would have given up a long time ago – once we clean up these teething issues up we will have the nicest little J going.

With the new governor and engine it is about 6 knots faster than the old engine – I think once we get it tuned in and running it will be a really nice ship.

Peter wrote:

Yes exactly, and the “suspected corrosion” cam+follower disintegrations are really rare on engines which have a proven regular flying record. In fact I have never heard of one.

I’m sure I’ve mentioned here the C172 that I learned to fly in – it was in out flying club in Houston and flew 1000 hours a year. I had to switch planes during my initial training due to the engine needing an overhaul at around 1200 hours due to camshaft spalling. However, that was a bit of a special case because it was the O-320-H2AD (where AD seems to mean ‘airworthiness directive’) which has a higher incidence of this kind of thing happening (which is too bad, because otherwise it’s a good engine and has a lower fuel burn than earlier O-320 engines).

Andreas IOM

Getting an engine to TBO is all about regular usage and engine operating temperature and it is all about illiminating the two biggest engine killers corrosion and lack of lubrication.

The UK’s biggest Lycoming fleet has almost all its engines make TBO simply because of high annual usage and getting the engine up to a good working temperature and because of the high usage the oil gets changed very regularly. As you might guess camshaft failure is practicly unknown to them. Some of this credit must go to the overhaul agency they use who are producing a high quality product.

Back in the late 1960’s and early 1970’s when CSE at Oxford rand a training school they had an approved maintenance program for their Lycoming engines that ran the bottom end to 4000 hours with the cylinders changed at 1000 hours and all this on straight oil ! once again this was a high usage operation that got its engines up to temperature and kept them there for a considerable time with the oil being changed regularly.

It follows that the best way to destroy an engine is to run short trips that don’t get the engine hot, leave the oil in the engine for months on end and don’t run the engine for weeks. The combination of moisture held within the oil and the lubricant slowly dropping from the camshaft are the killers as corrosion forms on the dry camshaft and when the engine does get started it runs dry untill the oil pressure builds sufficiently to get oil to the cams.

So the question is how to mitigate the problems of low usage ? First I would make sure the aircraft always gets enough flying to get the oil temperature to 180F for the best part of an hour. Second use a quality oil with a corrosion inhibiter. Third, change the oil at three months intervals. Forth , when you change the oil if you can’t fly remove the spark plugs and spin the engine on the starter until you make good oil pressure.

I’m not sure about using cam guard but I can’t see it doing any harm .

Most of this won’t be new to many of you but it’s worth saying for those new to aircraft ownership, I guess the bottom line is that an aircraft engine can cost you as much sitting around doing nothing as it can being flown.

All the valve guides were out of tolerance, when we removed the cylinders the cam was damaged with some minor corrosion and 2 of the lifters were starting to spall.
The compressions were good, oil pressure etc, if it had not been for the valve guides and the subsequent sticky valves it might have run for another couple of hundred hours, but for my peace of mind I am happy we went with the full teardown and repair.
I have a motor and accessories now which is prety much good as new, that makes flying a great deal more pleasurable.

WIth respect to the previous question, if an engine has done 150 hours in the last 4 years I would say the usage is low and the engine would be suspect, and it depends on the pattern of usage – running up 40 hours of usage over the summer months then leaving it idle for 6-8 months is obviously different than taking it up for a run once a week over the entire year.

Last Edited by aidanf123 at 24 Mar 06:03
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