O-290-D2 overhaul criteria

[Scott MacMoyle]

I'm overhauling my O-290-D2 for an STC install in my Colt. I've been able to source all the parts to constitute an overhaul by current Lycoming standards with the exception of the pistons. Lycomings list of mandatory replacement parts includes pistons. So here's my question. I have an O-290 specific Lycoming overhaul manual that Includes inspection criteria to overhaul the pistons. I plan to follow that and call the engine TSO 0 when I return it to service. Would anyone cry foul ?

Scott

 

[Bell206]

I plan to follow that and call the engine TSO 0 when I return it to service. Would anyone cry foul ?

 

[Scott MacMoyle]

I think my Lycoming O-290 overhaul manual complies with para (2). Also Lycoming SI's are considered the same as SB's according to AC 20-77B.

 

[Bell206]

I think my Lycoming O-290 overhaul manual complies with para (2)..

Yes. And in most OH manuals there usually is a statement in there that requires all OEM bulletins and ADs to be complied with at the same time as the overhaul.

 

[Scott MacMoyle]

Yes and that is in contrast with AC 20-77B which says SB's are only mandatory when associated with an AD or an airworthiness limitation or a few other reasons. AD's of course must be complied with.

Lycoming does everything with SI's. You cant even find a torque on a bolt without looking it up in an SI. So that makes it difficult but the older manual gives the torques and limits right in the manual.

So let me ask you.. A year from now you are asked to do a pre buy inspection on this awesome tailwheel Colt with new fabric new Garmin stuff and a TSO 0 engine. What do you tell your customer ?

You wont hurt my feelings either way. Im too old and ugly to be doing things under the cover of darkness. If Im going to do something Im going to do my homework and be willing to put it on the internet for all to read. Thats why Im asking. I want opinions. I think I have a leg to stand on here.

 

[Magman]

Do you have to actually have to call it an “ Overhaul”?

Lycoming wants it run with certified instruments in order to use the term.

It suddenly became just a “ Cam Replacement”!


Cylinder plans?

I had quite a mess and Lycoming , ECI and Gibson all said “ I don’t know “ when

we needed some info regarding their product.

It is sort of lengthy so I won’t elaborate unless there is interest.

 

[Bell206]

that is in contrast with AC 20-77B which says SB's are only mandatory when associated with an AD or an airworthiness limitation or a few other reasons.

Given 20-77 is an AC there is other guidance that sums it up better in that any OEM instructions are only mandatory when required by rule. So the AD is rule Part 39, the airworthiness limitations are rules Part 43 and Part 91, its rule Part 43.2 above that makes the overhaul manual mandatory as well to include its reference to all OEM bulletins. So technically it is not in contrast to the "acceptable" AC as the bulletins are mandatory by rule (43.2). If that makes sense to you.

So let me ask you.. A year from now you are asked to do a pre buy inspection on this awesome tailwheel Colt with new fabric new Garmin stuff and a TSO 0 engine. What do you tell your customer ?

Being a fan of field overhauls, if the work accomplished and the paperwork backed it up I'd tell my customer he had a solid aircraft in front of him and make an offer.

Lycoming wants it run with certified instruments in order to use the term.

Curious. What certified instruments would not be available to a mechanic at the field level that would prevent him from signing it off as an overhaul? Your comment implies he'd have difficulty to do that.

 

[Magman]

Fed guy said there must be a manometer , 4 cylinder CHT , oil temp and pressure,
Tach that had been calibrated. What they wanted was all instruments used in a
Test Cell and not in the aircraft. Since I had the log entry completed it was a simple matter to cross out Overhaul and insert Camshaft Replacement.
It flew later the same day. Flight school owner wanted the aircraft flying and
could care less what it was called. Ultimately flew about 3000 hrs.until the next overhaul.

 

[Bell206]

Fed guy said there must be a manometer ,

Interesting. Why was the fed guy there? While Lycoming and TCM require the use of calibrated indicators there is no requirement for it to be the equivelant of a test cell. They even provide alternate procedures to use the aircraft prop for the break-in process if a test club is unavailable. Seems more like the federales in your neck of the woods prefer making their own rules vs following the existing guidance based on this and your previous posts.

 

[Magman]

Routine surveillance. He has retired by now.

I agree with your comments. It was not cost effective in this case in keep it on the ground while either arguing or getting instruments. I considered doing instrumentation later but other matters were more important. Many folks would have insisted on the “SMOH”.

My take is that if every mfg requirement is not accomplished it can not be referred
to as an overhaul. Lycoming does provide Inspection Criteria to determine if the pistons can be serviceable. The conflict is they also require replacement at overhaul. My belief is the engine can be operated as a “ Repair” but not an “ Overhaul”.


Now I’m wondering if OP will get back on cylinder plans?

 

[Bell206]

Lycoming does provide Inspection Criteria to determine if the pistons can be serviceable. The conflict is they also require replacement at overhaul.

Are you sure piston replacement is a mandatory replacement item? Its been a long time but I don't recall this outside of several specific scenarios. I do recall piston pin replacements. There's a Lycoming SB that lists these items which unfortunately I cant get to at the moment. Do you have a reference to the piston replacement handy?

 

[Scott MacMoyle]

Its SB 240W and I just read it and wow. I was wrong. I thought i remember reading pistons but it only says piston pins, plugs and rings. So all this was just an excersize. Sorry guys. I do appretiate your comments. I did learn a lot from them. I do believe I could meet the requirements of 43.2 para (2) up to the word or. But now I dont have to.

 

[Scott MacMoyle]

Gibson says they can overhaul my cylinders and get rings. The cylinders will be chrome of course. They are out for chrome now.

 

[bnt83]

Engine overhaul logbook entries can be so vague it makes me throw up in my mouth thinking about one we owned.

I want to know everything about it. I want a detailed log entry and a scrapbook of every ink stamp, metal stamp, pick ticket, 8130, yellow tag etc. I want a picture of the crankshaft gear retaining bolt, retaining washer, camshaft data stamp, crankcase casting numbers, piston part numbers, crankshaft stamps, oil pump gear stamps, oil pump body stamps, everything that has data. I want copies of all the invoices a well.

I want photos of the oil pressure gauge, oil temp gauge, tachometer, hour meter, manifold pressure, fuel flow, cylinder head temperatures, exhaust gas temperatures, outside air temp, altitude, and how many quarts of oil were in it at the start of the flight - all recorded before the engine comes off.





And a summary of all reused parts, a reference to when they were installed and it condition at that time.

 

[Scott MacMoyle]

If I have to call it Time Since Major Repair I will but If I feel I have met the overhaul criteria I will call it that. As I say, I'm not going to go into any gray areas but I'm also going to take the regs at their word.

I have a problem with manufacturers who use safety as an excuse to generate revenue. As you may know from your screen name the Bell 206 has a 24 month airworthiness limitation on main rotor TT straps. How many of those have you changed with only 50-100 hours on them ? I've changed a couple myself. Thats always been a sore spot for me. Its purely revenue generation from Bell. they refuse to differentiate between 50 hours and 1000 hours on a part. I guess you could make the case that they wear just from static load sitting in the hangar but I think thats weak but I'm no engineer. Other aircraft have TT straps with no limit at all like the Hiller UH 12.

I take care of a G450 for my day job and Rolls Royce says the engines will have a mid life inspection every 10 years. Well when ten years came around they told me they were on strike and gave me a one year extension. Can you believe it ? Its a safety issue unless they are on strike. Guess what they would say if I asked for an extension when it suited me ?

We need support from manufacturers but we also need protection from them which is why I think its important they cant just do thinks by making them Gospel by SB.

 

[Scott MacMoyle]

Wow. Thats allot of info but I can see your frustration. I have a Grumman Tiger and I sent the engine off to Penn Yan for overhaul because I think the resale value would benifit from that sticker on the engine. If they would accept an O-290 I would have sent it to them and If new pistons and cylinders were available I would have bought them too but they simply are not. I think you might buy my Grumman but might pass on my Colt.

 

[Scott MacMoyle]

At the end of the day the buyer has to decide what they will accept. Ive had the same issues with the definition of damage history. If a damaged part is replaced there is no damage history but others might say no and still others just want to use it as a stick to beat you with during negitiations. Thats why I wont hide anything. It will all be in the logbook. If you like it buy it if you dont then pass. I dont want anybody coming back to me after the sale.

 

[bnt83]

Wow. Thats allot of info but I can see your frustration. I have a Grumman Tiger and I sent the engine off to Penn Yan for overhaul because I think the resale value would benifit from that sticker on the engine. If they would accept an O-290 I would have sent it to them and If new pistons and cylinders were available I would have bought them too but they simply are not. I think you might buy my Grumman but might pass on my Colt.

We have a factory zero timed O470 in a Cessna 182, the one-page log entry from Continental is...underwhelming. Meets industry standards of course.

 

[Doc Holliday]

We have a factory zero timed O470 in a Cessna 182, the one-page log entry from Continental is...underwhelming.

Doesn't Continental have a file on that engine with the info?

 

[bnt83]

Doesn't Continental have a file on that engine with the info?

No idea, probably all lost in hurricane by now.

 

[mondtster]

At the end of the day the buyer has to decide what they will accept. Ive had the same issues with the definition of damage history. If a damaged part is replaced there is no damage history but others might say no and still others just want to use it as a stick to beat you with during negitiations. Thats why I wont hide anything. It will all be in the logbook. If you like it buy it if you dont then pass. I dont want anybody coming back to me after the sale.

In my opinion, the value of the aircraft will suffer more from having an o-290 on it than it will from having an engine repair instead of an overhaul. So log the thing the best way you see fit and don’t worry about it.

 

[Bell206]

As you may know from your screen name the Bell 206 has a 24 month airworthiness limitation on main rotor TT straps. How many of those have you changed with only 50-100 hours on them ?

Actually quite a few as at the old day job we would swap out components to our training fleet that had small increments of time remaining to get our full dollars worth. But you'll find on the limits for the 206 TT straps it was a corrosion issue as related to the construction method and calendar time. The original TT straps had a higher life limit until several people slung a blade off. The current 206 TT straps both OEM and PMA have a 4 year limit and the same 1200 retirement. As to other aircraft the utilized "TT straps" having different limits they were made in a different manner but did have their own issues at times.

Guess what they would say if I asked for an extension when it suited me ?

They can and will provided you approach them properly. While TBO extensions require the FAA involvement I have gotten other extensions simply based on requirements for the aircraft. I learned this from the day job as we got extensions for a bunch of stuff from PT6 nozzle cleaning to transmission OHs. We even assisted the OEM in component/inspection extension due to our fleet size. Usually there's no requirements on the Part 91 side for this type of process so its not seen that much but definitely doable for a whole list of stuff.

the one-page log entry from Continental is...underwhelming.

FYI: While more info is good, you'll find that FAA guidance prefers the use of references vs long descriptive maintenance entries. And you'll also find a good number of A&Ps prefer the same to include myself. Long write ups do not guarantee anymore specificity than a simple write up referencing a single manual or paragraph. The only method I know of to know that level of detail is to perform the work in-house.

 

[Magman]

My comment on Mandatory Replacement was based on Scott’s original comment.

Bell’s clarification that is is not makes more sense.

BNT’s comments are something I can relate to.

After the sintered metal Oil Pump sharing the p/n with another of different material

and the O-540 Crank Bolt color AD I agree it’s wise to retain packaging or pix of

all installed items. Fortunately some of the big guys do. Phones work well here.


The O-290 has not been supported by Lycoming for quite a while.

The ones I’ve dealt with had unusual issues.

D Due to an oil dumping issue a Lyc Rep told me confidentially the

fix is to cut about 1/8 inch off the end of the Cam!


D2 - It began with 4 jugs with low compression on a low time engine.

Compression Rings were broken on all 4.

Jugs sent carbide / chrome process that were returned with new rings in Blister
Pack.

One ring had such a large “ free gap “ it would fall off the piston.

None of the 3 folks mentioned earlier would say “ that is correct”.

After lengthy research and Suprtcub.org we decided to install the furnished
rings.

The barrels were choked and the rings required grinding even more to obtain
specified ring gap when positioned in the cylinder.

Eventually all was done and the the engine has been fine.

My belief is they wanted a very high ring pressure on the carbide plated walls.

My guess is the folks that had done the Major did not check ring gap at the correct
position in the cylinder. Choked Cylinders require that.


I can email the entire conversation from the forum if requested.

 

[mondtster]

The O-290 has not been supported by Lycoming for quite a while.

The ones I’ve dealt with had unusual issues.

Same here. They are not my favorite engine, especially when they need extensive enough work to necessitate opening them up. I vowed to never overhaul another one after my last experience with one, which thankfully was my personal engine.

 

[Dana]

The big problem with the O-290 is parts availability. It's a little better on the experimental side; for example, Mack truck pistons and rings will fit...

 

[mondtster]

The big problem with the O-290 is parts availability. It's a little better on the experimental side; for example, Mack truck pistons and rings will fit...

Combustion Technologies has non PMA pistons available for them. A different application piston might have some advantages in the piston ring department however.

 

[Magman]

The issue is not only parts. “ Non- supported” means they pretty much disavow

any knowledge of the unit. They would say it is the right p/n and they have

X number in stock. They would not say if the ring was actually mfg. per spec.

10 years later I have yet to talk with anyone that has seen a ring able to fall off

the piston on ANY reciprocating engine. Engine is running fine though.

 

[Scott MacMoyle]

I went into this knowing the concerns about the engine. I decided to gamble on it. When I bought the Colt there where two O-290's sitting on the ground so I bought them figuring I could get one good crankshaft and 4 good jugs out of them. So far the first crankshaft was ground to .006 and the first 4 jugs I sent to Gibson had no cracks so thats good. The cam was reground and all the bearings were readily available at spruce. So far I have had no problems finding any parts. I realize pistons are extinct and exhaust valves are also rare but I havent had any issues yet. Gibson still has my jugs so I will have to wait to see what actually comes back.

My feeling is that you can buy O290 cores for very low money when compared to a O320. I did find out that the parts and labor from there are pretty similar so the core is where the real savings is. All told I think I can have an overhauled engine on the plane for 15K. Without cutting any corners. As much as I would like an O320 I dont think it can be done for anywhere near that price. Its just a 2 seater so it will perform better than the O235 it came with. Plus the STC is for O320's also so the next guy can do whatever he wants.

I did reach out to combustion technologies. They have no interest in certifing the pistons. I would be happy to work with them on an owner produced part route but it would still be a major alteration so I think I would need Fed involvement or at least DER involvement. rings are also avaiable with the same issues but Im told that rings for chrome cylinders are still available and thats all your going to need anyway.

I think I will be able to give this engine one last lease on life and I think I can get my moneys worth out of it. After that its the next guys problem. People operate Franklin engines and other unsupported engines all the time. I had a franklin in a helicopter years ago. Back when I sent my O360 to Pen Yann pre covid. I spent 26K plus the core was valued at 8K. I dont dare think what it would cost today. So I dont know what you can put an engine on a plane for but I think this gamble has a chance of working out.

 

[Papa Foxtrot]

I did reach out to combustion technologies. They have no interest in certifing the pistons. I would be happy to work with them on an owner produced part route but it would still be a major alteration so I think I would need Fed involvement or at least DER involvement.

You might try VARMA. Might come back a "hard no", but could be worth a shot - especially if the pistons have a good track record in experimentals. VARMA is supposed to be for "low risk" parts - not sure if pistons fit that description...

 

[Magman]

“The times they are a changing”.

O-235 C1 (Colt ,Super Cruiser, Super Cub ) and early O-330’s are rapidly

moving to the “ Endangered Species” as well. AFAIK the issue is parts availablity.

 

[Bell206]

on an owner produced part route but it would still be a major alteration

FYI: owner-produced part is not a major alteration as you are producing an identical approved part. But the data you use to produce the part must be approved. Several options on how to do that. A major alteration would be if you wanted to install the Combustion Tech pistons in your engine which is a possible route as well.

You might try VARMA.

Have you seen anything official from the FAA on VARMA? The only thing I've seen is from the EAA.

 

[Scott MacMoyle]

Combustion technology pistons are identical but they are forged not cast like the originals so I think that might be an issue with the owner produced part route as they wouldnt be identical. So approval would be needed for that change I would think.

 

[Bell206]

but they are forged not cast like the originals

Given they are forged might be a good candidate for an alteration. At a minimum you could install a set of those pistons, put your aircraft under experimental R&D or exhibition and see how they perform. Dont like them then replace with OEM pistons and go back to your standard AWC. Regardless, there are several routes to take all of which can be researched at a decent cost to see if you're interested.

 

[Papa Foxtrot]

Have you seen anything official from the FAA on VARMA? The only thing I've seen is from the EAA.

The EAA press release is all that I've seen. A web search shows a lot of links all referencing it also.

From this link:

How does it work?

VARMA will initially be managed by the Chicago ACO. Call them at 847-294-7357 with any proposal and they will determine if and how it can be approved.

I guess a call to the Chicago ACO would reveal if they've heard of it.

 

[Bell206]

I guess a call to the Chicago ACO would reveal if they've heard of it.

However, without any policy out in the public domain its still a moot issue. And the only way this will work within the system is if there is a regulation, Policy Letter, Order, or Advisory Circular explaining the process. There already exists a process to use off-the-shelf-parts on aircraft that doesn't require the ACO, however, the VARMA program will provide a path for pilots and owners to make this happen as well. Once the FAA releases their side game on.

 

[Papa Foxtrot]

However, without any policy out in the public domain its still a moot issue.

The link at eaa.com that I posted above specifically states that this is not a new policy. It also states that the only new document is a "work instruction" for FAA staff. If I had any interest, then I would call Chicago and ask for more information. Since my area of interest is EAB, it is definitely "moot" to me. I'm not defending the program.

As a side note, a member of my EAA chapter that is active in the Vintage/Classic space is of the opinion that this is actually messing up the current owner produced parts program by adding a layer of FAA involvement.

 

[Magman]

This thread somewhat describes the current state of GA engines. A potential

buyer would be wise to determine if the intended engine is in the growing family

of orphaned models. So far members include the Lycoming 290 series, O-235 C

and early 320’s. The O & GO 145 are the eldest members. Continental includes

GO-300 and some 4 cylinder models. I did have to wait 6 months for them to

produce an O -200 Accessory Case though.


Buying an aircraft only to find it’s out of service because of the unavailability

of 1 piston ring or 1 exhaust valve is frustrating at best. Yet it could easily happen

at any inspection. OEM Or PMA folks will only make what they can sell in volume

to recoup their investment. Their are some people that have cornered the market

on less numerous types such as Franklins and Jacob’s. Perhaps the list will grow?

 

[Bell206]

a member of my EAA chapter that is active in the Vintage/Classic space is of the opinion that this is actually messing up the current owner produced parts program by adding a layer of FAA involvement.

He really shouldnt be worried. Owner produced parts fall under Part 21 and do not require any FAA involvement so long as the data used to make the part is approved data. The main difference with VARMA is that by allowing the ACO to make a part "approved" it raises these parts to the "replacement" level same as a TSO but without the ability to sell them. While it may appear these are similar to owner produced they are not. As to the "work instructions" those are the Orders and Policy Letters I mentioned above. And while I didn't call the Chicago ACO have talked to those I know in other ACOs and they are waiting to see the same internal docs as well. Time will tell.