Engine Replacement/Trade-In/Swap/Buy New?

[Wakeup]

Hi. Not sure where you are located but I have only heard good things about Gann Aviation in North Georgia. He builds great engines and is very well known. I had my annual done at his shop and was very impressed. He has a separate shop where he only builds engines. Just my 2 cents. Troy

[triple8s]

I'll second Carlus Gann, other I had good experience with is Poplar Grove.

[1964-M20E]

I’m not  sure but I think when the time comes if I have a willing MX I’d take mine disassemble, send parts out for inspection, reconditioning, or replacement and then reassemble the engine myself with the MX.  This way I know what parts are in the engine, how it was assembled and exactly what was done to it.

[dcjohnst]

Wow, Thanks for all the replies! A lot of good stuff on here...

Well, it's finally gotten down to the nitty-gritty, and I just cut a check for a cool upper 20s k overhaul and re-mount. I always knew my precious bird needed love, I just didn't know how much! Welcome to GA aircraft ownership, or so they tell me... Jeez

Turns out that the steel in the oil filter --verified by very good metallurgist--was most likely left over from an incident eight years ago when she threw a lifter body for some unknown reason. Seems to me that they should have noticed something in the filter during the pre-buy inspection a year ago, but they say they didn't and I don't question it. But the chunk they found in the filter during my first annual this spring was nothing you could ignore and the shop wouldn't sign off, and I don't question that either. Just keep writin' those checks! No desire to mess around with a potentially lethal mechanical issue. So, I told 'em to do it up right like they were going to fly their kids in it. Makes my pocket book considerably lighter, but I sleep well at night and that's worth something. The shop (a very reputable one) tore down the engine and found nothing wrong! The camshaft was a bit worn and probably would have caused problems eventually, so I just went for an overhaul. I cried a little. And I don't drink, so it was real tears.

But now I have some new questions:

1) what's the difference between nitrided and nickel replacement cylinders?

2) is there any functional difference between an overhauled cylinder and a factory new one?

3) they don't offer roller tappets cams on overhaul. What am I missing? That is to say, what is all the fuss about roller tappets and what am I missing out on?

Thanks guys...

[MB65E]

Congrats on pulling the trigger. Well moving forward, I don't think you will regret the decision.

1. Nitrating is a hardening process, nickel is a coating on the cylinders. Much like the "chrome" cylinders of the past. There are some good benefits of chrome, there just hard to brake in, but do last a long time. I think the chrome processes they do now could be better than in the past. However, the Most common is Nitrating.

2. An Overhauled cylinder could have 5000 hrs on it. Lots of heat cycles on them. I've not seen too many cylinders with that make it past 4k with out cracking or major repairs done. A factory new cylinders will not have any heat cycles on them but run the risk of infant mortality, however that should be covered in a warranty program. I'd stick with what you have if you can verify how many times the cylinder had been overhauled. I'd say 1-2 times would be what I would shoot for to keep the reliability in the cylinder. Less than 3k hrs on each cylinder. 1x overhaul for sure. 2x probably ok. 3x be careful.

3. Lycoming's roller Cam engines adopt the "modern" roller tappets (I say modern but we all know Chevy has had roller tappets for a LONG time). To get the roller Cam, you need to change the case. They may be able to modify it depending on the -model... Maybe, I don't really know about the modification change itself.

Hope you can enjoy the new engine. Follow most of the brake in procedures listed here on the site, and change the oil often every 10hrs!

Good luck!

Matt

[NotarPilot]

Is there a limit in how many times you can OH an engine? I think my mechanic told me once or twice before the case isn't good anymore. Or something to that effect. My memory sucks sometimes.

[MB65E]

No limit, but I can tell you the only original part from 1965 on my io360a1a engine is the crank, one rod, and the lower sump. All other items have been scrapped over the years. 3900hrs...

Just did the 4 overhaul last year.

-Matt

[FlyWalt]

I am currently going thru a rebuild of our 231's engine at JB Engine Service in Sebring, FL. I will be happy to report our experience in detail when they finish assembly and deliver.

Regards,

W

[dcjohnst]

No limit, but I can tell you the only original part from 1965 on my io360a1a engine is the crank, one rod, and the lower sump. All other items have been scrapped over the years. 3900hrs...

Just did the 4 overhaul last year.

-Matt

Wow! Did the overhauls occur at regular intervals? Or do you find that you have had to OH more frequently as the engine gets older? When I used to work on ships it was pretty common to see 50 or 75 year old engines. If you maintain them properly (and sometimes even if you don't) they just keep puffing along...

[MB65E]

''67 tare down after gear up, '84 Major, '13 major. I guess I should have said 3rd OH, 4th run.

I had the crank race balanced this last time so hopefully it will pay off and at least not crack the case and Bank...

-Matt

[DaV8or]

My plane has it's original engine and it's never made TBO. It's been overhauled four times. 1st time at about 1100 hours due to the AD on the crank bearings. Owner decided to just do the whole engine. 2nd time it was a gear up at 1400, owner decided to just do the whole engine. 3rd time was at 1500 hours, the engine threw a rod and the plane dead sticked onto a golf course. The owner decided to do the whole engine. 4th time a crack was discovered on the case at the #2 cylinder and the owner had it welded and then a complete overhaul. We are now at 400 beyond that.

 

Somehow, I doubt it'll ever make it to TBO.

[fantom]

I am currently going thru a rebuild of our 231's engine at JB Engine Service in Sebring, FL. I will be happy to report our experience in detail when they finish assembly and deliver.

 

 

Will be interested in your experiences. They seem to be a fair and experienced outfit with very reasonable prices. Did you consider Zephyr Aircraft Engines?

[FlyWalt]

I considered Western Skyways, Zephyr, Certified Engines in Miami, and other one in Orlando whose name escapes me. We chose JB for the following reasons:

 

1. Competitive price

2. Willingness to come out and pick up the engine at my IA's shop

3. Verbal agreement to push us ahead in the schedule if he could

 

And most impressive

 

4. Willingness to come back to my IA's shop and set up the fuel system when the engine is installed.

 

I have been dealing with Jimmy Brod Jr.

 

I expect delivery this week. So lets keep our fingers crossed :-)

 

Cheers,
W

[AESpecialists]

I'll throw out a few things here in no particular order

 

Nitriding is a form of case-hardening. It's a process that yields a 'skin' of harder high carbon steel over a base of more ductile lower carbon steel. It's used on cranks, cams, and cylider bores to give a hard wear surface without making the whole item brittle. Cam failures provide a great example of how this works. Once the 'skin' is broken, the softer metal underneath wears away in a hurry.

 

Lycoming roller lifter engines have a different case, cam, lifters (obviously) pushrods, and pushrod tubes. The lifters are a mandatory replacement item in most cases. Pretty much if you can see them, you have to replace them. This makes a roller lifter engine notably more expensive to overhaul or properly inspect after a propstrike.  I believe the switch was made becuase of the frequency of cam failures in Lycoming engines, and the frequency of cam failures is (partly) a result of the EPA mandated removal of phosphates from lubricating oil stocks. Lycoming makes an additive to put the phosphate stuff back in. Also a good idea to use it on your MG BTW.

 

There isn't a hard and fast rule about how many times you can overhaul an engine, just how many times you can overhaul some of the parts. Cranks have a limited number of undersized grinds, and cases can only be line-bored so many times before they become too thin. Cams can be reground, but once the hardened skin is gone, that's it. Rods can be rebushed forever, but the big end can only be redone a finite number of times before the rod is 'too short' or the cap is too thin. Rocker arms can be rebushed, but the valve end can only be cleaned up so many times.

Given production tolerances, some individual  components can be redone a dozen time, another one may get one run and no more.

[carusoam]

AES,

Go ahead and introduce yourself. Are you the technical guy, sales guy, business owner, or all three?

Your knowledge is appreciated, I would be interested in a bit of who it's coming from.

Best regards,

-a-

[mooniac15u]

 

Nitriding is a form of case-hardening. It's a process that yields a 'skin' of harder high carbon steel over a base of more ductile lower carbon steel.

 

Nitriding does harden the steel but it doesn't make it higher carbon. The process adds nitrogen to the outer layer.

[AESpecialists]

Nitriding does harden the steel but it doesn't make it higher carbon. The process adds nitrogen to the outer layer.

 

  You are correct on the chemistry, sir. I was mixing up nitriding and carburizing in my head as I was typing. The net result is still a case hardened surface with a skin of hard material over a more ductile base.

[AESpecialists]

AES,

Go ahead and introduce yourself. Are you the technical guy, sales guy, business owner, or all three?

Your knowledge is appreciated, I would be interested in a bit of who it's coming from.

Best regards,

-a-

  My card reads Engine and Parts Sales, but I am also NDT tech, coordinate with the inspection staff, deal with vendors and tech reps, liase with the FAA, make coffee and, on a bad day, do facilities maintenance. I've been with this shop in various capacities for over seven years.

 My personal background is in antique aircraft, sporst car racing, and industrial archaeology.

 

Mark

[dcjohnst]

The saga of my nightmare first annual with my beloved M20J 'Allegro' is drawing to a close!

She went into the shop in late May for what should have been a quick turnaround annual. I had just bought her eight months earlier, and, I thought, what could possibly go wrong? She had an intermittent glitch with the auto-trim, but otherwise, she fulfilled all of my hopes and dreams for being an owner/pilot--something that I came to in my mid-50s. So, I had to replace the doughnuts, no big deal. The break fluid had hardened, so had to completely drain and replace that, not a simple job, but hey it's not gonna kill me. Turned out they had to pull out the servo and rebuild it to fix the intermittent auto-trim, OK, it's starting to add up. Then disaster! They found a finger-nail sized piece of steel in the oil filter. Weeks of testing with scopes and a full metallurgy analysis to make sure it wasn't just something left over from when she threw a lifter back in 2006. And, it turns out, that's what it was: just a piece of junk that had slowly worked its way through to the bottom of the engine and finally reached the filter. But the shop owner didn't want to sign off on the annual. So, off goes the IO-360 to Penn Yan for a rebuild. I am sweating the financing like a farmer at the bank trying to get a loan for next year's crop knowing he has cancer and will be dead before he can harvest the crop. What choice do you have? I ask you, brothers and sisters... And, of course, I'm worrying. I'm in good hands with a great Mooney mechanic at Freeway, but I'm still worrying. Should it be nitrided or chrome? Are they going to give me new cylinders or refurbished? (I'm good with nitrided and one rebuild, by the way.) Then, suddenly, the economy improves and every type of aviation shop is suddenly packed with business and my machine has to stand in line. She moves back out to my hangar. I check on her from week to week, but looking at her sitting up on blocks with a non-functioning engine block in her nose for balance just breaks my heart. It's like watching your old dog on life support. It ain't right. And I'm renting an old Piper Arrow on weekends and hating it--although I did learn a lot because it's a somewhat more forgiving experience. And here it is almost Thanksgiving, and FINALLY, the FedEx truck pulls into the shop driveway with MY ENGINE!!! I don't know how many of you have ever had the chance to un-crate a newly rebuilt engine, but for an old duffer like me, it's like being a 6 years old at Christmas all over again. It looks amazing, and they hang it back on the plane and she starts looking like an airplane again. A couple weeks later, the propeller comes back from being overhauled, and it's just as smooth as a baby's butt. A week after that, the servo gets put back in and the whole thing is re-attached to the flight director. It's practically a new airplane except for the control surfaces and skin which was all in good shape since she's always been hangared in good climates. I still can't fly her yet. The chief mechanic of the shop took her out for a sprint down the runway and the nosewheel started wagging this way and that like the wheel of a beat-up grocery shopping cart. Not sure what happened there but probably came out of adjustment when they replaced the doughnuts. There was a service bulletin awhile back that talks about the need for a washer-like shim that needs to be located at the top of the mechanism to keep the wheel aligned laterally. Evidently, you can't buy that part at Home Depot, so that will take a couple days. In the meantime, I'm practicing rough weather landings in the Arrow. I'll try to post a couple pics when they test fly her. I don't know if I'll ever be a true Mooney pilot, but I am certainly a true Mooney owner now. Or at least I've paid my dues. Thanks for your support and guidance folks.   

[DonMuncy]

Talk to one of the Mooney gurus, Tom Rousch, Paul Lowen or Don Maxwell. I don't know anything about it myself, but it is my impression that taking the nose gear stuff apart requires some careful reassembly (not readily apparent) to avoid that problem of not tracking straight.

[garytex]

If an IO 360 goes to Lycoming, doesn't it come back with the timing and data plate at 20 BTDC, instead of the 25 it started out with?  That would be enough for me to forgo a Lyc reman or OH. 

[carusoam]

Look up "8 second ride" for an explanation for wear induced wild rides in Mooneys. The nose gear is the culprit...

Best regards,

-a-

[jetdriven]

If an IO 360 goes to Lycoming, doesn't it come back with the timing and data plate at 20 BTDC, instead of the 25 it started out with?  That would be enough for me to forgo a Lyc reman or OH.

You can undo the service letter and set it to 25 degrees. I went round and round with lycoming on this already.

[jetdriven]

Look up "8 second ride" for an explanation for wear induced wild rides in Mooneys. The nose gear is the culprit...

Best regards,

-a-

You install the M20-202 washer in the nose gear. Ours used to swerve everywhere and it calmed it down.

[RobertGary1]

Be very happy you had a core to use. When my factory new (not remain, not rebuilt) engine disassembled I had no useful core other than a couple accessory gears. That about doubles the cost of replacement.