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Posted

Good question. I think it's only been 3-5 years. But I hear from a few anonymous voices at Lycoming that if they would have had DLC coated flat lifters 20 years ago, they wouldn't have bothered to develop roller lifters. 

I have a IO-360 A3B6D in my J, and from everything I've heard so far I wouldn't be afraid to overhaul it and use the DLC lifters. My problem is: the only cost effective way to get away from the D mag, is to trade it in on a IO-360 A3B6 factory re-man. Then you get the roller lifters which is fine, but you also get an engine with Slicks that are timed 20 degrees BTC instead of 25. 

I know, I know, I can change out the Slick's for individual Bendix's and get the 25 degrees. But it does all seem to get rather complicated.

Does anyone know how hard it is to start if you time the Slicks to 25? Theoretically the impulse coupling is now firing at 5 degrees BTC.

Posted

The cam isn’t ususly the problem.  Cams don’t cause lifters to spall, and nearly every one of them that’s opened up has several spalled lifters.  And another thing you can’t run two diamond coated surfaces together.  One must be softer. 

  • Like 1
Posted
On 8/11/2018 at 10:53 AM, John Mininger said:

Good question. 

Does anyone know how hard it is to start if you time the Slicks to 25? Theoretically the impulse coupling is now firing at 5 degrees BTC.

I’ve run my a3b6 at 20 and 25 over the years. I’ve never noticed any difference in starting or anything else really. 

-Robert 

Posted

Great tribology factoid, Byron!

Preferential wear on one surface or the other.  If they both are the same hardness... the wear is very high for both...

Something about material easily transferring from one surface to the other.   Making a rough surface, that sets up a grinding mechanism...

PP thoughts and old fuzzy memories only...

Best regards,

-a-

 

  • 2 months later...
Posted
17 minutes ago, Supercop0184 said:

Hey Paul - what do you know about Jewel??

Just what I've read on these forums and have talked with some on here who have used them. I know that I fully plan to send them my engine when it's time for the overhaul.

Posted (edited)
On 6/13/2018 at 9:37 AM, smlynarczyk said:

I am looking at a J with an engine approaching TBO and would consider buying the plane but need some cost estimates because I would opt to have an engine swap upon purchase.  I checked out the 2015 posting here on MS by (DHC)  and it seems like a pretty big ordeal (oil lines, hoses, prop governor, ...). Any insights into the  cost for going with the factory IO-360-A3B6? Also, a shop recommendation for that price? Any other considerations? Thx.

It’s around $65,000 and after installation probably about 70

Edited by jetdriven
Posted
4 minutes ago, jetdriven said:

It’s around $65,000 and after installation probably about 70

Minus the $20k core. That’s about what I paid for mine. My core was destroyed (disassembled in flight) but AirPower talked Lycoming into taking it since it was only 1000sfnew  

-Robert

Posted (edited)
On 8/11/2018 at 1:53 PM, John Mininger said:

Good question. I think it's only been 3-5 years. But I hear from a few anonymous voices at Lycoming that if they would have had DLC coated flat lifters 20 years ago, they wouldn't have bothered to develop roller lifters. 

I have a IO-360 A3B6D in my J, and from everything I've heard so far I wouldn't be afraid to overhaul it and use the DLC lifters. My problem is: the only cost effective way to get away from the D mag, is to trade it in on a IO-360 A3B6 factory re-man. Then you get the roller lifters which is fine, but you also get an engine with Slicks that are timed 20 degrees BTC instead of 25. 

I know, I know, I can change out the Slick's for individual Bendix's and get the 25 degrees. But it does all seem to get rather complicated.

Does anyone know how hard it is to start if you time the Slicks to 25? Theoretically the impulse coupling is now firing at 5 degrees BTC.

If memory serves, the slick 4345 is what you need for 20btdc.  (Internal start timing is changed is advanced for starting).   The 4347 is needed for 25btdc, the only difference is internal starting time is retarded 5 degrees compared to the 4345 and a different serial plate.  

If correct mag is used for the respective timing, then the start should be no different.   If you use 4345 with 25btdc timing, then you run a greater risk of kick back when starting.   If 4347 with 20btdc, then perhaps it will not fire quite as strongly on start up, but I think real world difference would be nil.  

Mag model numbers are going on memory, you need to verify and do your own research. 

On the Io-360-a1a, the 20btdc is an OPTIONAL SI..    that may be the case with other variants.   Undoing the SI is a PITA...  there are many engines in the field that actual timing does not match the data plate on the case.  

Edited by Browncbr1
Posted
On 10/28/2018 at 9:28 PM, RobertGary1 said:

Minus the $20k core. That’s about what I paid for mine. My core was destroyed (disassembled in flight) but AirPower talked Lycoming into taking it since it was only 1000sfnew  

-Robert

"Sfnew"

Since friggin new?

:)  

  • Haha 1
Posted
10 hours ago, Mcstealth said:

"Sfnew"

Since friggin new?

:)  

Yea if you think an early overhaul is the worst case wait until you throw a rod and the thing runs for 2 minutes dry trying to get you to an airport. One giant seized mess of solid metal. 

-Robert 

  • Sad 1
Posted
On 6/13/2018 at 11:56 AM, Antares said:

 I had Aero Engines of Winchester overhaul my IO360A1A and it cost me $23,500 for an overhaul with new flow-matched cylinders

 

Did that include accessories as well or just the core work?

Posted
On 6/16/2018 at 4:52 PM, toto said:

This has been widely discussed before, but I've always found Mike Busch's description of reman engines interesting:

Now, when TCM or Lycoming builds up a factory rebuilt engine (colloquially but incorrectly referred to as a "factory reman"), it pulls some "anonymous" case halves from one pile, an "anonymous" crankshaft from another pile, and so forth. When the engine is completely assembled, it gets a new data plate, a new serial number, and a new logbook.

The logbook starts out at zero time-in-service. Why zero? Because there's no other reasonable figure to put in the logbook. The case halves are certainly not zero-time, but there's no record of how much time they've accrued. The crankshaft may not be new, but there's no record of how much time is on the crank, either. And so on.

In short, the "zero-time" logbook that comes with a factory rebuilt engine in no way implies that the engine is "newer" or "better" than a field overhaul. All it implies is that the reused components in the engine are of unknown heritage...nobody knows how long they were in service prior to the time then were cleaned up, inspected, and reused in your engine!

https://www.avweb.com/news/maint/182849-1.html

Yup. Here's a simpler version for those who like pretty pictures-
 

 

Posted
On 10/28/2018 at 9:13 PM, gsxrpilot said:

Just what I've read on these forums and have talked with some on here who have used them. I know that I fully plan to send them my engine when it's time for the overhaul.

Great to hear brother!! Thanks!! Hope you’re doing well!!

  • Like 1
Posted
16 hours ago, RobertGary1 said:

Yea if you think an early overhaul is the worst case wait until you throw a rod and the thing runs for 2 minutes dry trying to get you to an airport. One giant seized mess of solid metal. 

-Robert 

I have to imagine anything causing a "thrown rod" would be caused by a top end problem?

Posted
13 hours ago, Raptor05121 said:

Yup. Here's a simpler version for those who like pretty pictures-
 

 

Actually, that video reaches the opposite conclusion of Mike Busch's comments from @toto--that rebuilds have a stochastically better outcome than overhauls, since you are more likely to have parts that have passed the infant mortality risk.

Posted
2 hours ago, jaylw314 said:

I have to imagine anything causing a "thrown rod" would be caused by a top end problem?

The famous Lycoming stretch bolt that secures the rod to the crank un-stretched itself. Why Lycoming doesn’t use a cotter key I don’t understand. 

-Robert 

Posted (edited)
2 hours ago, jaylw314 said:

Actually, that video reaches the opposite conclusion of Mike Busch's comments from @toto--that rebuilds have a stochastically better outcome than overhauls, since you are more likely to have parts that have passed the infant mortality risk.

True. The description above about reman not having previous hours because it’s made of random parts is so unrealistically pessimist as to be incorrect. If nothing else a reman has an extra years warranty than over a rebuilt for about the same money. A rebuild tolerance is tighter than an overhaul and realistically Lycomjng says its mostly new parts anyway. And the term reman isn’t something Lycomjng made up its a real term reserved for the certificate holder. 

For those of us with a total failure it’s about the only option An overhauler isn’t allowed to build an engine around your old dataplate  

-Robert 

Edited by RobertGary1
Posted
16 minutes ago, RobertGary1 said:

An overhauler isn’t allowed to build an engine around your old dataplate  

-Robert 

Source for that? Also, put another way, what cannot be replaced?

Posted
24 minutes ago, RobertGary1 said:

The famous Lycoming stretch bolt that secures the rod to the crank un-stretched itself. Why Lycoming doesn’t use a cotter key I don’t understand. 

-Robert 

Because it deosnt work. John Schwaner explains it in his book but a cotter key only keeps the nut from backing off. But a loose rod bolt fails in cyclic fatigue long before the nut loosens enough to fall off. And a properly torqued nut wont come off. An overtorqued bolt fails in tension. And a faulty bolt will fail regardless. 

  • Like 3
Posted
5 minutes ago, jetdriven said:

Because it deosnt work. John Schwaner explains it in his book but a cotter key only keeps the nut from backing off. But a loose rod bolt fails in cyclic fatigue long before the nut loosens enough to fall off. And a properly torqued nut wont come off. An overtorqued bolt fails in tension. And a faulty bolt will fail regardless. 

So that type of failure sounds like manufacturing defect rather than just wear over time?

Is this the sort of thing that would require opening the crankcase to detect, or would it be detectable with the cylinder off?

Posted
1 hour ago, jetdriven said:

Source for that? Also, put another way, what cannot be replaced?

Source that you can’t take a dataplate off a chunk of metal and build a new engine and attach that dataplate?

 

-Robert 

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