Overhauled angle valve cylinder blues

[jetdriven]

The runout airplanes we found were only 5-10K cheaper than the midtime ones. Some were the same price too.

[jetdriven]

Quote: M016576

My guess: lack of use + corrosion prior to me purchasing the aircraft.  Kind of hard to believe it takes a couple hundred hours of flight to manifest itself though... Hard to say.  I've gone the "more affordable" route than Byron and had the motor overhauled by a local shop and the jugs overhauled rather than new: total cost of OH: 17.5 AMU's... About half of what a FRM on a A3B6 costs from Lyc.  We'll see if it goes past 1000 smoh to make it worth it!!

[N601RX]

dp

[N601RX]

I ended up with a little under $14K in a field overhaul done in my shop at home with my IA's help.  That included remove and reinstall with me providing most of the labor.  I did choose to keep some of my accessories (starter, alternator, vac pump, one mag) as they were low time and easily changed later if needed.  My cylinders were still standard sized and fell within new limit sizes and were overhauled using all new parts. The case, crank and rods were reused, being overhauled to new limits. Everything else was new including gear train, pushrods, even nuts and throughbolts. All external hardware was replated. The bottom end was dynamically balanced and the Centri-lub STC was added to the cam. The Lycoming overhaul cost twice this, will it last twice as long? Time will tell.

The best I could tell from the shops I talked to is that this would have cost around $23K if I had sent it out to them, but then I wouldn't have had the satisfaction of putting it back together.  The downside is that you really don't get any warrenty doing it this way, but the savings more than made up for it.

[KSMooniac]

Good luck, Job and Mike.  I'm still chugging along on a 1991 factory overhaul (even installed by Lycoming in PA).  I have a suspicion but no proof that there was a lot of rampant outsourcing and cost-cutting in PA later that decade that has resulted in a lot of premature failures of cams and lifters.  Hard to say, impossible to prove without insider info.  They've had their rash of SBs and ADs on many different components after that time period.  I'm still too gun-shy to try any of their new tech until a lot of it goes thru a full TBO run without shelling out.

[M016576]

Quote: jetdriven

The factory A3B6 was $27,500 list.  We balanced that with a 19K rebuilt cylinder and new cam overhaul that would go 1300 hours.   New cylinder shop overhaul was in the 23 range. Still no roller cam.

[jetdriven]

Jim, I think both you and Scott are right. Ever notice all the guys with the rash of cam and lifter failures had their engine overhauled around the late 1990's or newer?   I think something changed with the suppliers around then. FWIW our previous engine was OH in 2001 with a new cam and reground tappets.

[M016576]

Quote: KSMooniac

Good luck, Job and Mike.  I'm still chugging along on a 1991 factory overhaul (even installed by Lycoming in PA).  I have a suspicion but no proof that there was a lot of rampant outsourcing and cost-cutting in PA later that decade that has resulted in a lot of premature failures of cams and lifters.  Hard to say, impossible to prove without insider info.  They've had their rash of SBs and ADs on many different components after that time period.  I'm still too gun-shy to try any of their new tech until a lot of it goes thru a full TBO run without shelling out.

[jetdriven]

The extra cost of an unplanned midtime overhaul was far more significant that the additional 5K the roller tappets cost to get.  That dual mag may  end up being a 5K item before too long due to non-availability of parts.

The loss of perfomrance (5-7 KTAS) is a real bummer.  I got confirmation that going to 25 degrees timing does not void the warranty, i am just corresponding with them a little more before pulling the trigger.

[M016576]

From a future cost mitigation standpoint, you made the right choice going with the A3B6 over the A3B6D IMHO.  I would have done the same of I had the extra money.  But I need that 10+k to keep flying (fuel, oil, other parts) in the near term.  I can now start rebuilding my "emergency fund" and if I have to cross this road again when my warranty on the OH runs out (4 years from now), then I will be ready.  If not, then I made the right choice in not spending the extra money up front.

It was more risky to go with the OEM motor and have it overhauled, but to "get my money out of it" vs buying from the factory all I need to do is hit 1200 or so hours on the OH, the rest is "on the house.". I still haven't finished installing the motor yet, so I have no idea how it's running vs my pre OH A3B6D.  I am happy, though, that it's the "devil I know" as far as fuel injectors, mag, setup, etc.  I'm also happy about the continued use of 25D mag timing.  Sounds like you're making good progress on that front with the A3B6 though, so more of a non-issue going forward.

[jetdriven]

FWIW my first choice was to split the case, swap the cam and tappets, and then reassemble with new bearings, rings, and mandatory items.  ~7K. Then run it to 2500 hours.    The shop I work with didnt want to do it. 

[M016576]

Quote: jetdriven

FWIW my first choice was to split the case, swap the cam and tappets, and then reassemble with new bearings, rings, and mandatory items.  ~7K. Then run it to 2500 hours.    The shop I work with didnt want to do it. 

[jetdriven]

I had a 1987 Mustang GT and a 1986 Camaro Z-28.  Both had roller lifters.   I hear Lycoming sourced Delphi (a GM supplier) for the roller lifters.  So, you got that right, 1980s technology. 1 trillion vehicle miles travelled, and someone decided to put them in aircraft.

FWIW my friend's R-1325 in his 1946 T-6 Texan has roller tappets too.

[carusoam]

Byron,

tuned port on the ’87 camaro looks a lot like balanced intake on my '94 IO-550!

If I could get some electronic ignition, not the 90’s opti spark though.  That is known to die every 60k miles.  I have one apart in my driveway currently....

The optical encoder gets dirty and fails to plan B....Then croaks during high humidity weather.

My dream engine is my current ride + electronic ignition.

Imagine selecting your timing, 20 or 25 degrees, by clicking on your mouse, or blue tooth iPad thing...?

I have simple dreams.

-a-