Cracked ring on #4 cylinder

[Shadrach]

1 hour ago, M20F said:

What is unknown?  You know you have an either new cylinder or an overhauled one depending on which you choose.  You potentially still have no idea about the core or the other 3 cylinders. 

 Time in service for the overhauled cylinders is unknown. I know it’s anecdotal, but it seems that there’s evidence that suggests that lycoming cylinders are good for single overhaul. That means if I want to be cheap and I ran my engine conservatively during its first run, I might consider overhauling my cylinders when it’s time to renew the engine. Buying overhauled cylinders with unknown history is a bigger gamble, much more so if they’re going on a low time bottom end. New Lycoming cylinders tend to go TBO and beyond on a NA lyc 360s baring the odd installation mistake or abusive engine management. How is it that we have no idea about the other three cylinders? He has an engine log just like the rest of us. I know that my engine had four factory new cylinders Installed at overhaul 19 years ago. They currently have about 1300SNEW. The OP stated that his cylinders have 500 hours on them but  didn’t state whether they were factory new or overhauled at the time of installation.   This would be good to know.   It would certainly affect my decision making process.  If they’re all overhauled cores with unknown history and two are not repairable, I’d consider topping it with four new lyc cylinders with the hopes of running them for at least the next 2000hrs.

Edited February 19, 2019 by Shadrach

[mschmuff]

Thanks for all of the input my fellow keyboard warriors!! lol 

Here is the additional information you are looking for.  The engine is at just over 1000 SMOH which was done in the 90's as a field overhaul.  This plane sat for 5 years prior to my purchase.  At 500 hours I did a top overhaul with first run cylinders. At 600 hours my lifter were spalling and wrecked my cam.   So I am replacing the #2 & #4 cylinders with overhauled cylinders.  I could have saved some $$ by having them bore out my cylinders but didn't have the time nor did I want different sizes on my engine.  And yes, as someone mentioned, I am concerned about my #1 & #3 cylinders.  Although the shop said they wouldn't replace them until they show a reason.  Low compression/wet plugs/etc.  They could not identify any reason why the ring broke.  No cracking in the cylinder itself.  He said that I was flying the way I should be whether it is LOP or ROP.  Compression's have always been good at above 74 for every annual.  First couple annuals were 78x4. 

As for new lycoming cylinders will make 2000hrs easy.....The shop has 1500 cylinders currently in their pipeline, they say the Lycoming cylinders have huge problems.  This is NOT my opinion, this is me simply regurgitating what was said to me from someone I would consider an expert in the field.  And also this may be a recent (last 5-8 years) with Lycoming.  They should be installed by tomorrow and I'll go start the break in process.

Another bit of advice he gave was since the introduction of multi-weight / synthetic blend oils the amount of cylinder failure has gone through the roof!!  I am switching to 100W 50SAE from here out.

[neilpilot]

11 minutes ago, mschmuff said:

I am switching to 100W 50SAE from here out.

Agree that straight weight mineral oil is preferable, but you might consider 80w going into the winter, and 100w spring thru fall.

Edited February 19, 2019 by neilpilot

[Shadrach]

15 minutes ago, mschmuff said:

As for new lycoming cylinders will make 2000hrs easy.....The shop has 1500 cylinders currently in their pipeline, they say the Lycoming cylinders have huge problems.  This is NOT my opinion, this is me simply regurgitating what was said to me from someone I would consider an expert in the field.  And also this may be a recent (last 5-8 years) with Lycoming.  They should be installed by tomorrow and I'll go start the break in process.

Another bit of advice he gave was since the introduction of multi-weight / synthetic blend oils the amount of cylinder failure has gone through the roof!!  I am switching to 100W 50SAE from here out.

Very few issues on my end.  I think that age and inactivity are the biggest culprits.  I am trying to conceive of how multi-viscosity oil mineral oil would cause cylinder problems.

3 minutes ago, neilpilot said:

Agree that straight weight mineral oil is preferable, but you might consider 80w going into the winter, and 100w spring thru fall.

What data are you using to form this opinion? is it anecdotal? is there a study or test that shows this to be true?  Please expound on this.

[Guest]

Our local flight school with around 30 Lycoming powered aircraft run W-80 & W-100 and LW16702 Lycoming additive only in the engines requiring it.  They routinely see 3500-4000 of flight time between overhauls.  No multi grades oils ever.

Clarence

[neilpilot]

8 minutes ago, Shadrach said:

15 minutes ago, neilpilot said:

Agree that straight weight mineral oil is preferable, but you might consider 80w going into the winter, and 100w spring thru fall.

What data are you using to form this opinion? is it anecdotal? is there a study or test that shows this to be true?  Please expound on this.

Do you disagree?  I've been using Lycoming Service Instruction No. 1014M, Lubricating Oil Recommendations.  100w is recommended above 60F ambient air temperature.  80w is recommended in the 30F-90F ambient range, and should also reduce wear during colder starts.  https://www.lycoming.com/sites/default/files/Lubricating Oil Recommendations.pdf

[skydvrboy]

49 minutes ago, M20Doc said:

Our local flight school with around 30 Lycoming powered aircraft run W-80 & W-100 and LW16702 Lycoming additive only in the engines requiring it.  They routinely see 3500-4000 of flight time between overhauls.  No multi grades oils ever.

Clarence

I'd also bet they see a fair bit more action than <40 hrs per year the average GA pilot flies.  That may have a LOT more to do with the TBO than any choice of oil.

[jaylw314]

1 hour ago, Shadrach said:

Very few issues on my end.  I think that age and inactivity are the biggest culprits.  I am trying to conceive of how multi-viscosity oil mineral oil would cause cylinder problems.

What data are you using to form this opinion? is it anecdotal? is there a study or test that shows this to be true?  Please expound on this.

IIRC, there were problems developing full synthetic multi-weight oils because the multi-weight compounds don't play well with lead, right?  I never got a clear idea of what that actually meant and what the consequences were, though.

I'm not sure how they solved this with the current aviation multi-weight oils, but I think there is still some distrust about it (aside from the fact that most operating manuals only specify single-weight oils).  And then Mike Busch recommended against multi-weight oils based on only the intuitive idea that single-weight oils stay thicker when cold and would adhere to metal for longer during periods of disuse. He's never produced any actual data to support that idea, though, and I'm guessing there isn't any data out there.

[Shadrach]

5 hours ago, neilpilot said:

Do you disagree?  I've been using Lycoming Service Instruction No. 1014M, Lubricating Oil Recommendations.  100w is recommended above 60F ambient air temperature.  80w is recommended in the 30F-90F ambient range, and should also reduce wear during colder starts.  https://www.lycoming.com/sites/default/files/Lubricating Oil Recommendations.pdf

I don’t think that staight weight oil is a bad idea if you’re able to attain the appropriate engine/oil temperature before start up.

You’ll have to excuse me for being a bit dubious on like Lycoming’s recommendation.

 They also state the following:

For most Lycoming models, preheat should be applied anytime temperatures are at 10˚ F or lower.

https://www.lycoming.com/content/operating-cold-weather

So To be clear, according to Lycoming it’s perfectly fine to crank your cold soaked airplane that’s been sitting for two days at 12°F with straight 80W oil in the case.

Does that seem like well considered advice to you?

Edited February 19, 2019 by Shadrach

[neilpilot]

27 minutes ago, Shadrach said:

 They also state the following:

For most Lycoming models, preheat should be applied anytime temperatures are at 10˚ F or lower.

https://www.lycoming.com/content/operating-cold-weather

So To be clear, according to Lycoming it’s perfectly fine to crank your cold soaked airplane that’s been sitting for two days at 12°F with straight 80W oil in the case.

Does that seem like well considered advice to you?

I offered a reference as to why I'd recommend a seasonal switch between 80W and 100W, and I stand by that comment.  Anything else is beyond my initial comment.

[carusoam]

Some things come to mind...

Sort of a review list, as this thread is getting long...

1) Two cylinders misbehaving at the same time... sort of odd...

2) How LOP have you been flying? Only during cruise?  °F LOP?

3) How ROP have you been flying? °F ROP?

4) Did you replace the cam and spalled lifters?

5) 25 years since SMOH, and a long inactivity in the middle...

Did I get all that correct?

Best regards,

-a-

[Guest]

4 hours ago, skydvrboy said:

I'd also bet they see a fair bit more action than <40 hrs per year the average GA pilot flies.  That may have a LOT more to do with the TBO than any choice of oil.

They do fly a lot of hours, but they had more engine issues and shorter lives while on multi grade oils (Phillips 20W50XC) I don’t think they’ve ever sent an oil sample, but do cut the filters for examination.

Their O-235 usually see a top overhaul at the 2400 hour TBO and then fly on till around 3500-4000 hours. 

Operating hours in Canada are calculated by time up to time down not hour meter, so in reality they have 20-25% more running hours than flight hours, making it even more amazing.

Clarence

[jetdriven]

6 hours ago, mschmuff said:

Thanks for all of the input my fellow keyboard warriors!! lol 

Here is the additional information you are looking for.  The engine is at just over 1000 SMOH which was done in the 90's as a field overhaul.  This plane sat for 5 years prior to my purchase.  At 500 hours I did a top overhaul with first run cylinders. At 600 hours my lifter were spalling and wrecked my cam.   So I am replacing the #2 & #4 cylinders with overhauled cylinders.  I could have saved some $$ by having them bore out my cylinders but didn't have the time nor did I want different sizes on my engine.  And yes, as someone mentioned, I am concerned about my #1 & #3 cylinders.  Although the shop said they wouldn't replace them until they show a reason.  Low compression/wet plugs/etc.  They could not identify any reason why the ring broke.  No cracking in the cylinder itself.  He said that I was flying the way I should be whether it is LOP or ROP.  Compression's have always been good at above 74 for every annual.  First couple annuals were 78x4. 

As for new lycoming cylinders will make 2000hrs easy.....The shop has 1500 cylinders currently in their pipeline, they say the Lycoming cylinders have huge problems.  This is NOT my opinion, this is me simply regurgitating what was said to me from someone I would consider an expert in the field.  And also this may be a recent (last 5-8 years) with Lycoming.  They should be installed by tomorrow and I'll go start the break in process.

Another bit of advice he gave was since the introduction of multi-weight / synthetic blend oils the amount of cylinder failure has gone through the roof!!  I am switching to 100W 50SAE from here out.

Philips X/C 20W50 aviation oil was introduced in 1976..... My friend has a supercharged IO-780 with over 500 HP.  he uses X/C tooo..I dont think it matters, theyre both the same viscosity at operating temp. \

[skydvrboy]

11 hours ago, neilpilot said:

Do you disagree?  I've been using Lycoming Service Instruction No. 1014M, Lubricating Oil Recommendations.  100w is recommended above 60F ambient air temperature.  80w is recommended in the 30F-90F ambient range, and should also reduce wear during colder starts.  https://www.lycoming.com/sites/default/files/Lubricating Oil Recommendations.pdf

What am i missing here?  Under Part 1 - Lubricating Oil Recommendations, the first one listed is 15W50 or 20W50 for all operating temps.  Is there somewhere they are recommending straight weight oil over multi-viscosity that I'm not seeing?