Overhaul or IRAN on a mid-time engine?

[MBDiagMan]

You mean for the whole job, not just for repairing the case, right?

[MikeOH]

Another perspective:  As a BUYER, I loved that the PO had done an IRAN for a cracked case at 1600 hours.  He put in a new cam, lifters and bearings.  Then, over the next 500 hours all 4 cylinders were replaced.  With, technically, 2100 hours SMOH I bought the plane at a run-out engine price.  To me, I bought with a 500 hour bottom end, and even less on the jugs!  300 hours later and I've had zero reason to regret my purchase decision.  As someone said earlier, the buyer isn't going to care that you did the bottom end...when it comes to price, that is!

It has always fascinated me that we think nothing of IRAN on a car engine, but look for any excuse to spend the coin for a complete OH when it comes to airplanes.

[ArtVandelay]

Another perspective:  As a BUYER, I loved that the PO had done an IRAN for a cracked case at 1600 hours.  He put in a new cam, lifters and bearings.  Then, over the next 500 hours all 4 cylinders were replaced.  With, technically, 2100 hours SMOH I bought the plane at a run-out engine price.  To me, I bought with a 500 hour bottom end, and even less on the jugs!  300 hours later and I've had zero reason to regret my purchase decision.  As someone said earlier, the buyer isn't going to care that you did the bottom end...when it comes to price, that is!

It has always fascinated me that we think nothing of IRAN on a car engine, but look for any excuse to spend the coin for a complete OH when it comes to airplanes.

Good for you, but bad for the seller, who could have ask a lot more for a 500 SMOH than the 2100 runout.

The OP could be the seller someday.

[MikeOH]

1 hour ago, ArtVandelay said:

Good for you, but bad for the seller, who could have ask a lot more for a 500 SMOH than the 2100 runout.

The OP could be the seller someday.

That was my point

[MBDiagMan]

Well there is some logic to being quicker on the trigger with an aircraft engine overhaul.  With your road vehicle you just coast to the side of the road and call somebody if it quits.  When an aircraft engine quits you have a much different set of options.

[MikeOH]

3 hours ago, MBDiagMan said:

Well there is some logic to being quicker on the trigger with an aircraft engine overhaul.  With your road vehicle you just coast to the side of the road and call somebody if it quits.  When an aircraft engine quits you have a much different set of options.

No question about being quick to fix versus a road vehicle.

But, why is an IRAN so frowned upon?  I don't get how properly fixing what needs to be fixed is inherently more risky than the 'quick on the trigger' OH?

[MBDiagMan]

I think I now understand your question.

I’m not an aircraft mechanic, but I grew up in my Dad’s auto repair business in the days when valve jobs and in frame overhauls were very common, so I think I have some experience and understanding that transfers to the subject to some degree.

If repairs, and that’s what IRAN is, are done by a competent, experienced and conscientious tech under the correct conditions and circumstances, then there’s absolutely nothing wrong with it.  Most aircraft owners are NOT mechanics and often they’re flying is well funded.  As I said earlier, the stakes are higher with the reliability of an aircraft engine.

I am currently going through what began as an IRAN on my IO-360 A1A.  It began by making metal.  Upon inspection we discovered the need for cam and lifters.  We thought that we would be able to simply split it, replace cam, lifters and maybe bearings and be good to go, but we knew that you can never know until after tear down.  Once apart it was apparent that the case and crankshaft were questionable to the point of needing to be sent to the machine shop for proper evaluation.  Once we know we were going that far, then it was apparent that a zero time overhaul was the better approach.  Many factors were part of this equation including engine time and cylinder condition.

Most people don’t understand engines and many in aviation can afford a fresh engine and naturally feel that an engine shop MUST be better than one rebuilt in a hangar in the boondocks.  Perception is reality.  If you perceive the more expensive engine to be more reliable because you paid more money for it AND you can easily afford it, then that is your perception and you will fork over the money.

When you head into an IRAN always realize that it must come apart and keep in mind that you never know what you’re going to find.  If you realize that, you can do the repair and properly inspect everything then decide whether to continue with repair, overhaul or exchange at an engine shop.

Repairing is fine as long as you don’t lose sight of the big picture.

My $0.02,

[JamesMooney]

So in my situation, someone else is covering the cost for the case. They also covered the R&R cost.

The case is open already, and I believe the shop has done an IRAN inspection (am re-confirming with the shop today).

But even with those costs being 'covered' elsewhere, it's a big jump from IRAN to O/H. I have basically 4 price points in front of me:

1. Put the engine as-is back together in the new case, get back flying - $10,600

2. Pre-emptively do a new cam + lifters, then get back flying - $13,400

3. Pre-emptively do roller case, roller tappets, and roller cam - $17,700

4. Go the full distance and do the overhaul - $26,400 <- jump in price is b/c this includes a prop + governor overhaul, fuel sys, mags (but I'm not sure if this includes the cylinders being o/h'd and they are 2nd run already - am calling the engine shop today to re-confirm)

 

According to VRef, the overhaul adds $13k-15k value to the plane. I hear everyone's argument that an overhaul improves the value of the plane, but that's still money tied up in the value of the plane, not in your bank or investments (investments which probably have a better ROI over 5-8 years than does value in the plane?  ).

 

I could also do any of these along the way now:

(a) Muffler ($700) <- the exhaust flame tubes are burnt out

(b) Starter ($600) <- its a 20-year old starter

(c) SureFly mag install ($1500) <- now may be the time to do this

(d) O/H & re-coat the engine baffles ($200)

(e) Install a JPI830 or JPI930 - $5000 / $7000 (currently has a US-8A engine analyzer, 4 cyl but shows only 1 EGT/CHT at a time/cycle through)

(f) Prop and prop governor o/h - $3500 <- 16 years since done last

(g) Fuel sys o/h - $2000 <- 20 years since done last, assuming I don't do the engine O/H but just want to pre-emptively do this

 

Engine currently is 900 hours. I have no intent on selling in the next 5-8 years. I fly 150-200 hours/year.

So based on putting 900 more hours on the plane in the next 6 years, I could either:

- IRAN: Spend $13k now, plus unknown over next 6 years depending on how the cylinders behave, and $30k O/H in 6 years, to end up with a zero-time engine in 6 years

- O/H: Spend $26k now, to zero time and end up back at a 900-hour engine in 6 years

I think I'm talking myself into the O/H now... along with the new starter and installing a SureFly mag... and will do the JPI830/JPI930 in the future (keeping the existing US-8A engine analyzer)

Thoughts?

 

[MBDiagMan]

Canuck,

This is nothing except my opinion formed after extensive reading about the cam/lifters situation, but I believe that if you go with your choice number two, make sure you use the latest DLC coated lifters.  From the current indications they will improve your chances of ongoing cam and lifter health as much as the roller solution.

My $0.02,

[JamesMooney]

1 hour ago, MBDiagMan said:

Canuck,

This is nothing except my opinion formed after extensive reading about the cam/lifters situation, but I believe that if you go with your choice number two, make sure you use the latest DLC coated lifters.  From the current indications they will improve your chances of ongoing cam and lifter health as much as the roller solution.

My $0.02,

Thanks MB! Definitely would go DLC coated, for sure.

I just spoke with the shop and they were skeptical on the roller cam option (my option #3) ... it's an extra $6-8k, compared to DLC coated flat tappets. 

[Ragsf15e]

Personally I’d do the cam and dlc lifters and be done.  The cylinders and accessories can be done without cracking the engine case again and with it still on the airplane when they actually need it.

[A64Pilot]

Some of you have noticed that the cost of a factory zero timed engine isn’t all that much more than a field overhaul.

‘That’s by design, both Continental and Lycoming have been raising prices of their parts, and discounting their overhauls, one assumes one pays for the other.

‘It’s simply a way to keep the doors open and your people employed since the new engine builds are a fraction of what they were back in the day, I don’t believe it’s they are evil and squeezing the small shops out of business, but that’s occurring, wheth3r by design or not.

[A64Pilot]

On 3/14/2021 at 12:56 PM, MikeOH said:

 

It has always fascinated me that we think nothing of IRAN on a car engine, but look for any excuse to spend the coin for a complete OH when it comes to airplanes.

It’s very rare for an automobile to outlast the engine anymore, and even rarer for an engine to be overhauled. Most of the time if an engine is to be replaced on say a delivery van etc, it’s almost always a short or a long block, the only time an engine is removed and overhauled is if it’s some kind of rare hard to find motor and you haven’t a choice, so actually cars long ago went to the model of the exchange overhaul, which is what a zero timed aircraft engine is, so aviation is following the auto model.

 

But Auto’s are a different maintenance model entirely, no one does an annual inspection on an automobile, but historically it’s been shown that if you want a vehicle to last indefinitely, then some sort of recurring major inspection is the way to get there. ARMY does it for trucks and tanks etc., but not on a schedule, it’s after major “events”.

‘An overhaul is a form of recurring engine inspection, once in a blue moon, everything is disassembled, cleaned and inspected, and all high wear items replaced.

You can try to convince yourself that your doing the same thing piecemeal, but your not. For instance in the bottom end IRAN was the case sent off for inspection and repair, how about the accy case gears for Magnaflux? 

Edited March 17, 2021 by A64Pilot

[JamesMooney]

Thanks all for the input. I think I'm going to go the IRAN route. 

When the dust settles, the overhaul is quickly pushing $30k ... whereas IRAN, with new cam and lifters, is half that.

I may do a few bottom-end things and may get the prop IRAN'd too - preventive stuff.

I'll still be $12-15k ahead - and the engine is not even half time (900 hours).

That gives me ~8 years to plan for an overhaul --- maybe more, maybe less, but who knows either way even with an o/h.

[MikeOH]

11 hours ago, A64Pilot said:

It’s very rare for an automobile to outlast the engine anymore, and even rarer for an engine to be overhauled. Most of the time if an engine is to be replaced on say a delivery van etc, it’s almost always a short or a long block, the only time an engine is removed and overhauled is if it’s some kind of rare hard to find motor and you haven’t a choice, so actually cars long ago went to the model of the exchange overhaul, which is what a zero timed aircraft engine is, so aviation is following the auto model.

 

But Auto’s are a different maintenance model entirely, no one does an annual inspection on an automobile, but historically it’s been shown that if you want a vehicle to last indefinitely, then some sort of recurring major inspection is the way to get there. ARMY does it for trucks and tanks etc., but not on a schedule, it’s after major “events”.

‘An overhaul is a form of recurring engine inspection, once in a blue moon, everything is disassembled, cleaned and inspected, and all high wear items replaced.

You can try to convince yourself that your doing the same thing piecemeal, but your not. For instance in the bottom end IRAN was the case sent off for inspection and repair, how about the accy case gears for Magnaflux? 

WHOOSH!!!

[Igor_U]

22 hours ago, FlyingCanuck said:

Thanks all for the input. I think I'm going to go the IRAN route. 

When the dust settles, the overhaul is quickly pushing $30k ... whereas IRAN, with new cam and lifters, is half that.

I may do a few bottom-end things and may get the prop IRAN'd too - preventive stuff.

I'll still be $12-15k ahead - and the engine is not even half time (900 hours).

That gives me ~8 years to plan for an overhaul --- maybe more, maybe less, but who knows either way even with an o/h.

This sounds like a plan! This would also reduce the downtime which is considerable these days for OH or rebuild. Lets hope they don't find any surprise when take apart the engine.

Good luck.