Which Engine Would You Choose?

[Rotorhead]

Extremely long story short, I'm in the market for another IO-360 A3B6D. 

If you had 2 options to choose from, which would you choose?

1) A disassembled engine that had an overspeed but then inspected and yellow tagged on the case, camshaft and crank? It has sat for 19 years but doesn't show any signs of corrosion/wear and tear. TT1385 130hrs on pistons and pins. Located in Spokane WA

2) A fully complete engine that has sat for 6 years with 432 TTSN and 85 since IRAN in 2017. Internals are unknown and a boroscope has not been completed. Located in southern New Jersey

Yes, I know there are other engine options out there but I want to focus on these 2 specific choices.

-KC

Edited November 19, 2023 by Rotorhead

[EricJ]

Those are gonna depend highly on your own risk tolerance and what value they represent to you compared to the prices.    Either could be good depending on the mix of those factors.

Also FWIW Alan Fox has an entire firewall forward assembly for sale right now.   Listed for $30k iirc.   I think it's in the classifieds here right now.

[M20F]

The price on the two engines would be relevant. 

[LANCECASPER]

9 hours ago, EricJ said:

Also FWIW Alan Fox has an entire firewall forward assembly for sale right now.   Listed for $30k iirc.   I think it's in the classifieds here right now.

That sounds like the second engine mentioned above.

[LANCECASPER]

On 11/18/2023 at 10:24 PM, Rotorhead said:

Extremely long story short, I'm in the market for another IO-360 A3B6D. 

If you had 2 options to choose from, which would you choose?

1) A disassembled engine that had an overspeed but then inspected and yellow tagged on the case, camshaft and crank? It has sat for 19 years but doesn't show any signs of corrosion/wear and tear. TT1385 130hrs on pistons and pins. Located in Spokane WA

2) A fully complete engine that has sat for 6 years with 432 TTSN and 85 since IRAN in 2017. Internals are unknown and a boroscope has not been completed. Located in southern New Jersey

Yes, I know there are other engine options out there but I want to focus on these 2 specific choices.

-KC

Neither. You've already had a bad series of events with your engine.

 

 

Going into another possibility of an additional $30,000 down the drain would just add to your misery. I would see if Lycoming would take yours as a core and put the money you would spend on one of these toward a factory reman.

 

[Tx_Aggie]

I’d plan on trading your core to Lycoming and grabbing a reman io-390. Claw back about 10 knots in cruise apparently. 

[Utah20Gflyer]

Given those two options I’d go with #1 because you state it has been verified to have no corrosion.  Corrosion is the number 1 concern with used engines.   A new or reman engine might provide a lower life cycle cost and better functionality.   

[Tx_Aggie]

3 hours ago, bluehighwayflyer said:

Let’s see.  5% more horsepower on take off.  Maybe 2% more horsepower in cruise. Likely no perceptible difference in cruise speed, by my estimation, beyond whatever you can pick up via the new Top Prop that is also required by the STC.  

I’m going by the guy that posted the data. @bmcconnaha has several threads on the empirical data after his io-390 install.

don’t be one of those folks who peddle a bunch of “likely”, “maybe” and “estimation” without facts.

Btw our “200 hp” io-360s are actually 193 hp. 

[takair]

Do you know—-How bad was the overspeed?  I think that might help decide. 

[Shadrach]

 

7 hours ago, Tx_Aggie said:

I’m going by the guy that posted the data. @bmcconnaha has several threads on the empirical data after his io-390 install.

don’t be one of those folks who peddle a bunch of “likely”, “maybe” and “estimation” without facts.

Btw our “200 hp” io-360s are actually 193 hp. 

I’m sorry but you seem confused about what constitutes a fact.

1) Please offer some semblance of supporting data for the claim about IO360 rated horsepower? There are certainly variances from engine to engine. The different timing specs of various 200hp IO360s might factor in to some degree. That variance might even be as much as the 3.5% you claim (doubtful). The idea that Lycoming and the FAA have conspired to “over rate” the IO 360 seems unlikely.

2) One person’s anecdotal observations on an upgrade they just sent 10s of 1000s to install are not likely unbiased, nor do they negate the laws of physics. 
 

3) The 5% difference in max rated power is not nearly enough to add 10kts. Furthermore the delta diminishes at cruise power. 70% is 147hp for 390 and 140 for 360. 
 

I don’t begrudge anyone’s choice to go with an IO390, but to me it feels like the answer to a question that no one asked.

[Echo]

#1 without knowing price.  #1 Even more if it is significantly less expensive than #2.

#2 is a crapshoot.  At least you KNOW what #1 is (inside and out)...

SHARE THE COST!  Huge factor in decision.

[EricJ]

One significant advantage of the IO-390 is that they're still making a reasonable quantity of them new for the experimental market.    It's a popular engine for RV-14s, among others.   So that likely increases the chances that the support level for that particular model will remain decent for the foreseeable future. 

Given Van's recent woes, though, how big of an advantage that may continue to be might change.

 

 

[Shadrach]

On 11/18/2023 at 11:24 PM, Rotorhead said:

Extremely long story short, I'm in the market for another IO-360 A3B6D. 

If you had 2 options to choose from, which would you choose?

1) A disassembled engine that had an overspeed but then inspected and yellow tagged on the case, camshaft and crank? It has sat for 19 years but doesn't show any signs of corrosion/wear and tear. TT1385 130hrs on pistons and pins. Located in Spokane WA

2) A fully complete engine that has sat for 6 years with 432 TTSN and 85 since IRAN in 2017. Internals are unknown and a boroscope has not been completed. Located in southern New Jersey

Yes, I know there are other engine options out there but I want to focus on these 2 specific choices.

-KC

Where are you located? Honestly, either could be viable.

Some questions about each:

#1 Is the engine still disassembled?  The overspend would not bother me. How long has it been stored and how long since it was yellow tagged are concerns.

#2 Where was it during its 6 year hiatus? Was it properly pickled or living outside on an unused airplane filled with old oil?
 

Old Lycomings can be a crap shoot, but they’re not as fragile as they’re made out to be. We only hear about the horror stories. No one talks about engines that sit for years and suffer no ill effects but there are plenty that do. My original engine averaged 57hrs a year before it was OH’d but some years it didn’t fly at all or just got a few flights. No ill effects from sitting for mine, but others have deteriorated badly with lack of use.

The cost of splitting the case to inspect an already removed engine is pretty minor in the whole scheme of things. You need to find the right shop to do it but dropping a few grand for piece of mind might be the way to go.

[Pinecone]

1 hour ago, Shadrach said:

Furthermore the delta diminishes at cruise power. 70% is 147hp for 390 and 140 for 360. 

That is still a 5% difference.

I don't know the standards for aircraft engines, but for cars, from the best to the worst case in a specific engine can be well over 10%.

I know that BMW dyno tests each engine and they are required to be within the range of 0 - +10% of rated HP.  Other companies do not test each each engine, and typically the rated HP is the max that will come off the assembly line.  So it would not be unusual for you to be 10% down from the rated HP.

[Rotorhead]

52 minutes ago, Shadrach said:

Where are you located? Honestly, either could be viable.

Some questions about each:

#1 Is the engine still disassembled?  The overspend would not bother me. How long has it been stored and how long since it was yellow tagged are concerns.

#2 Where was it during its 6 year hiatus? Was it properly pickled or living outside on an unused airplane filled with old oil?
 

Old Lycomings can be a crap shoot, but they’re not as fragile as they’re made out to be. We only hear about the horror stories. No one talks about engines that sit for years and suffer no ill effects but there are plenty that do. My original engine averaged 57hrs a year before it was OH’d but some years it didn’t fly at all or just got a few flights. No ill effects from sitting for mine, but others have deteriorated badly with lack of use.

The cost of splitting the case to inspect am already removed engine is pretty minor in the whole scheme of things. You need to find the right shop to do it but dropping a few grand for piece of mind might be the way to go.

@Shadrach I'm located in Albuquerque NM.

#1 engine is still disassembled and has been for the past 19 years in Spokane WA. Yellow tagged for that whole time.

#2 has been stored inside just like it landed and was parked for 6 years. It's in New Jersey 40miles off the coast.

Agreed splitting the case would bring great peace of mind, but could obviously go down another path of throwing another $5-10k into it if things don't look great.

I think that's the gamble, having a disassembled engine that can already be inspected essentially but are all the parts there or a fully assembled very low time engine that has mysteries inside.

 

-KC

[Shadrach]

1 hour ago, Pinecone said:

That is still a 5% difference.

I don't know the standards for aircraft engines, but for cars, from the best to the worst case in a specific engine can be well over 10%.

I know that BMW dyno tests each engine and they are required to be within the range of 0 - +10% of rated HP.  Other companies do not test each each engine, and typically the rated HP is the max that will come off the assembly line.  So it would not be unusual for you to be 10% down from the rated HP.

And we’re just talking engines. Dynamometers are equally inconsistent. They are good for tuning to a desired point on the curve, not so good for delivering actual power and torque numbers. 

[Shadrach]

1 hour ago, Rotorhead said:

@Shadrach I'm located in Albuquerque NM.

#1 engine is still disassembled and has been for the past 19 years in Spokane WA. Yellow tagged for that whole time.

#2 has been stored inside just like it landed and was parked for 6 years. It's in New Jersey 40miles off the coast.

Agreed splitting the case would bring great peace of mind, but could obviously go down another path of throwing another $5-10k into it if things don't look great.

I think that's the gamble, having a disassembled engine that can already be inspected essentially but are all the parts there or a fully assembled very low time engine that has mysteries inside.

 

-KC

The condition of the engine in Washington is verifiable, the assembly is the variable.

Then engine in Jersey is of unknown condition but is assembled and was running when put away.

Which one of those variables is easier for you to mitigate? Is there a significant price delta?

If it were me and I could negotiate an acceptable price, I would likely choose #1. However, that is because I have an engine shop that is 30miles from my home drome with whom I have previously worked. I would have them IRAN with DLC lifters. 

 

[EricJ]

13 minutes ago, Shadrach said:

And we’re just talking engines. Dynamometers are equally inconsistent. They are good for tuning to a desired point on the curve, not so good for delivering actual power and torque numbers. 

There's likely more variance in the operator than the dyno.   I worked compliance in our racing organization for many years, including for national competitions, and at big events we'd put dozens of cars on the dyno every day for compliance checking, since they were power limited by the rules.   With a good operator they're very repeatable within reasonably tight tolerance.    That was with inertia-only drum chassis dynamometers.    A loaded dyno, like would be used with just an engine, has a bit more operator dependence but can still be pretty consistent.    They kind of have to be so that A-B testing is useful to know whether changes are making a desired difference or not.

In my experience consistency was a fraction of a percent.   For many years at national competitions we only gave 1hp grace on somebody going over their declared hp.   It was pretty rare for people who were even reasonably careful to be surprised by going over.   Most people's results were consistent with what they'd submitted from their own local dyno.   Often somebody who got surprised by going over had originally dynoed after a fresh rebuild so that a compliance check after tolerances loosened up a little would "unexpectedly" make more power.    That works if you don't get selected for compliance check. 

Anyway, just a data point.   Loaded engine dynos are a little different, but should still be pretty repeatable.

[Shadrach]

5 minutes ago, EricJ said:

There's likely more variance in the operator than the dyno.   I worked compliance in our racing organization for many years, including for national competitions, and at big events we'd put dozens of cars on the dyno every day for compliance checking, since they were power limited by the rules.   With a good operator they're very repeatable within reasonably tight tolerance.    That was with inertia-only drum chassis dynamometers.    A loaded dyno, like would be used with just an engine, has a bit more operator dependence but can still be pretty consistent.    They kind of have to be so that A-B testing is useful to know whether changes are making a desired difference or not.

In my experience consistency was a fraction of a percent.   For many years at national competitions we only gave 1hp grace on somebody going over their declared hp.   It was pretty rare for people who were even reasonably careful to be surprised by going over.   Most people's results were consistent with what they'd submitted from their own local dyno.   Often somebody who got surprised by going over had originally dynoed after a fresh rebuild so that a compliance check after tolerances loosened up a little would "unexpectedly" make more power.    That works if you don't get selected for compliance check. 

Anyway, just a data point.   Loaded engine dynos are a little different, but should still be pretty repeatable.

I’m talking chassis dynos. My experience (likely limited compared to yours ) is that there is a notable difference from one shop to the next. HP/TQ relationship is consistent, so from a tuning standpoint the engine is likely to get to the same place.  Different dynos, in different shops, operated by different operators yield notably different results on my experience. Especially when we’re talking about a delta of 10hp. I would think a loaded, engine dyno would be far more accurate and consistent.

[Parker_Woodruff]

4 hours ago, EricJ said:

One significant advantage of the IO-390 is that they're still making a reasonable quantity of them new for the experimental market.

 

 

and Cirrus SR20.

[EricJ]

2 hours ago, Shadrach said:

I’m talking chassis dynos. My experience (likely limited compared to yours ) is that there is a notable difference from one shop to the next. HP/TQ relationship is consistent, so from a tuning standpoint the engine is likely to get to the same place.  Different dynos, in different shops, operated by different operators yield notably different results on my experience. Especially when we’re talking about a delta of 10hp. I would think a loaded, engine dyno would be far more accurate and consistent.

In our organization the type of dyno was specified, essentially it had to be a Dynojet, and even the models of dynojets were limited a bit.   Competitors had to have a dyno sheet on an approved dyno model showing their claimed performance and that was part of their classing determination.   At national events competitors came from all over the country and we'd still find decent consistency with the on-site dyno (a mobile Dynojet dyno, usualy the same operator at every event).   But you're right, variations across brands of dynos could be big, and variations across types of dynos could be significant, too (e.g., inertial-only to loaded).    So, yes, moving around between shops, especially if it changed brands/types of dynos, or the weather station was old and busted, etc., could make a lot of difference, but consistency among like types in proper condition with decent operators is usually pretty low. 

So, yeah, my previous statements were made in that context.   You're right, random shop visits could have high variance depending on the circumstances, but if you control the selections a bit then repeatability gets very good.

[Pinecone]

5 hours ago, Shadrach said:

And we’re just talking engines. Dynamometers are equally inconsistent. They are good for tuning to a desired point on the curve, not so good for delivering actual power and torque numbers. 

An ENGINE dyno is very accurate.  A chassis dyno, not so much.

[Pinecone]

4 hours ago, Shadrach said:

I’m talking chassis dynos. My experience (likely limited compared to yours ) is that there is a notable difference from one shop to the next. HP/TQ relationship is consistent, so from a tuning standpoint the engine is likely to get to the same place.  Different dynos, in different shops, operated by different operators yield notably different results on my experience. Especially when we’re talking about a delta of 10hp. I would think a loaded, engine dyno would be far more accurate and consistent.

I think much of that is operator difference.  And yes, between brands.   And this is assuming the shop has had their calibrated properly and at the recommended interval.

 

[Rotorhead]

11 hours ago, Echo said:

#1 without knowing price.  #1 Even more if it is significantly less expensive than #2.

#2 is a crapshoot.  At least you KNOW what #1 is (inside and out)...

SHARE THE COST!  Huge factor in decision.

@Echo

#1 is $14k

#2 is $30k

[Shadrach]

49 minutes ago, Rotorhead said:

@Echo

#1 is $14k

#2 is $30k

Wow…I’m out of touch. I would have thought they’d be close.