Lycoming io-360 Engine odyssey

[PT20J]

On 3/23/2019 at 10:45 PM, aidanf said:

for the lifters they have a diamond coating to prevent spalling, for the cam I have not heard of anything - I went with a superior cam anyway on the recommendation of my mechanic.

Common wisdom is that the lifters go first and take out the camshaft. Radial engines have used roller tappets since the 1930s and are free of tappet/cam gear issues. Maybe diamond dust is good, but all new and rebuolt Lycoming factory engines come with roller lifters which should solve the problem.

[aidanf]

Fingers crossed it will be ready on Friday - flying out to pick her up

[Guest]

It’s looking very nice!  You might consider sealing around the starter and crankcase with some silicone sealant, also using a piece of silicone baffle material make a crescent shaped piece to close the hole around the alternator once the prop is on and the belt tensioned.

Clarence

[mooniac15u]

On 3/26/2019 at 7:50 PM, PT20J said:

Common wisdom is that the lifters go first and take out the camshaft. Radial engines have used roller tappets since the 1930s and are free of tappet/cam gear issues. Maybe diamond dust is good, but all new and rebuolt Lycoming factory engines come with roller lifters which should solve the problem.

FWIW, it's not diamond dust it's an amorphous carbon coating called DLC (Diamond-Like Carbon).  It has very high hardness and a very low coefficient of friction.  You can read about DLC properties here:  https://en.wikipedia.org/wiki/Diamond-like_carbon

[testwest]

Any updates on this post? I for one am really really curious how those new CMI (Continental Prime) cylinders are working out.....

Edited April 14, 2019 by testwest
added Continental Prime to clarify the CMI acronym

[carusoam]

Pinging @aidanf to see if he is checking in...

Best regards,

-a-

[aidanf]

sorry - I have been having a lot of difficulties the last week connecting to the mooneyspace forum site - Sad story is that my mechanic was called away to support the red bull team and I had to delay going out to pick it up - this is maddening, the plane is ready but I need him available for an inspection after the first flight at least.

Now scheduled to pick it up on the 8th of May

[aidanf]

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 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.

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 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

[carusoam]

Aidan,

There are a couple of different EGT probes that JPI has used over the years...

Some are slow to react to temp changes, making it hard to lean accurately and quickly at the same time...

Since they are typically thermocouples... it is difficult to have them ‘stick’ at any one reading...

Check to see what model JPI you have and what probes you have... the more modern the better... errors in readings are often related to what probe is being used specifically on the cylinder that has the ship’s CHT gauge in it...

Some factory CHT probes are thermistors.  Check to see how your engine was instrumented for cylinder three... There is one TC well and you have two probes... JPI has a modern ‘piggy back’ probe for the TC well... you might have a spark plug TC that is ‘crummy’, week, and really not located very well...

EGT sensors are in a tough environment... they can fail with the number of hours they have... easy to test by swapping TC wires... to see if the problem is real and stays with the cylinder... or it moves with the failing sensor...

 

Nothing more fun than engine break-in flights... high power, low altitude, because you have to....  

Good luck with your next steps...

PP thoughts only, not a mechanic...

Best regards,

-a-

[MB65E]

Move some spark plugs around, sounds fouled to me. Not uncommon.

-Matt

[jaylw314]

IIRC, on the J, the factory CHT is a thermocouple on the #3 cylinder.  Some old JPI installations still have the spark plug gasket CHT probe on the #3 cylinder, but most newer installations will have the piggyback sensor that goes under the factory CHT probe.  I'm not even sure JPI still makes the spark plug gasket probe.

Your motor is a little too young to get Lycoming morning sickness, so I'd agree fouled plugs is the most likely.  I suspect you've been running rich all the time so far since you're breaking in the motor, and that you might not have leaned it aggressively on the ground for taxiing?

[aidanf]

Actually found 2 plugs slightly loose - which messed up the fuel mixture which caused the engine to run badly - so that's fixed - now we have a fuel servo issue - the engine idles ok but once you advance the throttle a bit it goes to full power and no adjustment possible - have to cut the mixture to shut it down - maybe just a bit of dirt in the servo - don't know but if I need to get the servo done that's another 2k down the drain.

 

[aidanf]

She is home  - finally - flew her down from Strasbourg to Bordeaux on Friday(3hours) - had to keep her low as I am still running her in, so given that it was the hottest day in June on record it was a matter of keeping hydrated.

Engine started up and ran beautifully all the way down - keep running it rich at the moment until its fully bedded in but the CHTs dropped off after about 2 hours of hard running (nickel carbide coated cylinders), 157knots(little to no wind) groundspeed at 6000 feet, 28 degrees C OAT, 12.5 gallons per hour, only used a couple of ounces of oil on the flight down -

After I change the oil at 10 hours I will start experimenting with LOP -

 

and oh yeah - I needed a new fuel servo - the failure mode was a cylinder dropping off (ie no ignition - no cht etc) when the engine was accelerated past 1300 rpm --

 

[carusoam]

Great pirep/update Aidan!

Good luck with the rest of the break-in flights... sounds like you have the important hours behind you already!

See if you can find any indications of the rings seating, in the CHT graphs of the engine monitor...

There might be interesting step like traces, if they exist...

Best regards,

-a-

[Raptor05121]

Amazing job. That engine and baffling looks gorgeous

[bradp]

What’s the little red devil in the background of the photos? 

[carusoam]

Guessing...  Chipmunk (de havilland) https://en.m.wikipedia.org/wiki/De_Havilland_Canada_DHC-1_Chipmunk

-a-

[aidanf]

So as a follow up to the engine odyssey.
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.

[carusoam]

Aidan,

Great update! Thanks for sharing the details...

Consider an update for the TC that is under the spark plug...

There is a similar ring type TC that fits under the TC well... the temp difference is only +25°F but the maintenance induced failure is greatly reduced...

The JPI website has both versions... under the plug and under the TC well.

PP thoughts only, not a mechanic.

Best regards,

-a-

[bradp]

Yes the piggyback bayonet probes are superior.