Convert Lycoming IO-360-A3B6D to IO-360-A3B6?

[Oldguy]

When @Rmag wrote about the 205 he restored, this was one of the items he described in the first post. Not being an A/P or anything close, this was the first I had heard of this being done, and my search of MS only turned up one thread where this was discussed in the realm of 20 vs 25 timing. Is this something available to those of us with the D3000 mag or is this an undertaking more easily solved by replacing the engine?

I ask because there have been other threads (like the one by @dhc) where the conversion from the "D" to the non-D has been described with all of its associated changes and complexities. As I look at the O/H of my engine in the upcoming years, the cylinders, crankcase and the rest of the engine have done well. It was a factory reman when it was installed and, with the exception of the single mag, I would put the exact same engine in it if I could.

TIA for any information offered.

[201er]

I did a trade in during factory reman for a a3b6 instead. Not only was it convenient but it was even cheaper as well. Another reason to get a core exchange factory engine now is to get the roller tappets on the cam as well. The mags are just half the story.

[Rmag]

201er's advice is best if you are at overhaul.  The only reason I did not do that was because my engine was off getting some work done and it was not close to overhaul time.

[carusoam]

OH Objectives:

1) get 25°BTDC timing.  Better power and efficiency (cost is higher CHTs)

2) get roller lifters. Better for what ails the IO360's cam/lifter combo... (corroded moon surfaced lifters grind through cam lobes)

3) get separate mags. Because two drive systems seems to be better than one.  (Independence)

4) get the mags that don't have plastic gears made out of nylon that are sensitive to ozone.

5) get the cam that has oil holes drilled in it.

6) If the Ney nozzles are available, make sure they can't fall out of their installation locations.

7) make sure the valves are ground, finished, ported, or whatever it is called to make them close properly.

8) cylinder surfaces... chrome is out. Nitrided sounds familiar(?)

9) Electronic ignition systems are coming.  Being able to swap out a whole mag might be more flexible this way...

10) Get instructions for engine break-in.  No guesses on best practices...

This is all stuff I read about here on MS. I don't have an IO360 in my plane.  But, if I did, these would be important to my decision making...

Best regards,

-a-

Edited May 17, 2017 by carusoam

[201er]

3 hours ago, bluehighwayflyer said:

To me the only time this conversion makes sense is when you are due for an engine overhaul and elect as @201er and @jetdriven did for a factory reman exchange, because then you also get the roller tappet cam and a lower exchange price.  The downside of the conversion, though, is that with the factory reman A3B6 comes crap Slick mags and a Kelly starter and alternator, not to mention 20 degree timing.  All of these negatives can be undone if you are willing to invest the time and money, but it is a hassle that could be avoided entirely with a field overhaul of the original A3B6D.

Right on except for a few clarifications. First off, the factory reman doesn't come with an alternator. You keep your old one. The starter is alright, at least for a while till you gotta change it. The slick mags suck. The 20deg timing robs you of about 5-7kts! It does run cold and smooth but it ain't worth it. Also bad for LOP operations. I ran the slicks for about 100 hours to finish the break in and get my money's worth and then I sold them and went to the bendix. That was a really good deal! I got some money back for the slicks and the speed gained on the timing change was more cost effective than any speed mod. Of course this wasn't more speed than on the previous engine but to get back what was lost. The amount I saved on the core change basically paid for the change to bendix mags. So figure for the cost of a factory reman of A3B6D you can get A3B6 with slick mags changed for bendix but as separate mags and roller tappet.

A few reasons to get away from the dual mag at the next possible convenience: there's s lot of speculation about them not supporting those mags in the future, two is more redundancy than one, simpler timing adjustment matching independent mags, cheaper maintenance of separate mags in the future.

Another downside is an overhaul comes with Champion Massive Plugs. Basically you can't get anything selling them so you might as well use them up and then get Tempest Fine Wires. I got about 700 hours out of the Massives. Starter is still good. Alternator came off last engine so had over a 1000 I put on it plus whatever prior.

[aaronk25]

And then there is the crap factory parts where they can seem to get their quality control and metallurgy handled, evident by really high iron counts and then be told by the factory "it's normal" or my factory cam that made it 400 hours in 2 years, now that was not a roller cam but why do the reground cams make it to overhaul and some of the factory ones come apart?


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[Jeev]

6 hours ago, 201er said:

I did a trade in during factory reman for a a3b6 instead. Not only was it convenient but it was even cheaper as well. Another reason to get a core exchange factory engine now is to get the roller tappets on the cam as well. The mags are just half the story.

I did the same thing about 4 years ago, it was an easy switch and as 201er said was cheaper.  If I remember correctly all I had to do was change the prop governor and the mounting plate for it.  I will take a look at my logs next time I'm at the airport.

Edited May 17, 2017 by Jeev

[Jeev]

1 hour ago, 201er said:

I ran the slicks for about 100 hours to finish the break in and get my money's worth and then I sold them and went to the bendix. That was a really good deal! I got some money back for the slicks and the speed gained on the timing change was more cost effective than any speed mod. Of course this wasn't more speed than on the previous engine but to get back what was lost. The amount I saved on the core change basically paid for the change to bendix mags. So figure for the cost of a factory reman of A3B6D you can get A3B6 with slick mags changed for bendix but as separate mags and roller tappet.

 

Do you have the part numbers for the bendix?  I am still running the slicks and would like to switch them out.

[Bob - S50]

We have a couple years until we get to that point, but did any of you consider a factory exchange for an IO390 instead of the IO360?  Why or why not?

Having never done an overhaul yet, I assume they ship the remanufactured engine to you and you send the core back.  Any reason why you couldn't take the fine wires out of the core and put them in the reman and put the massives back in the core before shipping it back?  Same with the starter.  Take the Skytec off the core and swap it with what the factory sends?

[Oldguy]

Thanks for all of the input.

While I am happy with my D3000, I share the concern of parts availability and their cost in the future. Plus, the availability of the electronic ignition is attractive to me. I figure about 3 more years at my current rate before it is at or beyond TBO which will put me a year away from retirement. I think I will go ahead and start sourcing the parts needed for the conversion at this point and do the conversion via trade-in.

Thanks again.

[KSMooniac]

Lycoming is known to be flexible a bit when they're motivated to get stuff engines back like our -D models. They might take an old one back just to get it out of circulation.

 

I opted to rebuild my '91 factory overhaul in 2015 instead of exchange. Doubt I'll be ready for another before it turns 35 but who knows. Lots can change by then!

 

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[preinke]

The factory allowed my '77 engine as an exchange but only for Reman - not overhaul. There are a couple more Mooney parts for the prop governor conversion that DHC documented - only a bushing on control arm wasn't descibed . His thorough description has saved us many hours - a big thank you ! I hope to be back in the air next week. My original intention was to work with what I had but the factory overhaul became cost effective but because of the age Reman was only option.

[Oldguy]

1 hour ago, bluehighwayflyer said:

I have adopted the same strategy and am on roughly the same schedule, Oldguy. Attached is a photograph of the only Mooney-specific part you need for the conversion. A new prop governor bracket. Mine was ordered and made during the Mooney slow down; hence the handwriting.  Be advised that it is also my understanding that Lycoming will not accept your core as an exchange on a factory reman if it was installed over 35 years ago. 

 

52 minutes ago, KSMooniac said:

Lycoming is known to be flexible a bit when they're motivated to get stuff engines back like our -D models. They might take an old one back just to get it out of circulation.

I opted to rebuild my '91 factory overhaul in 2015 instead of exchange. Doubt I'll be ready for another before it turns 35 but who knows. Lots can change by then!

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I think will be good on the expiration time. Mine was installed in September 2003, so if the time limit is 35 years I should run it out before I meet the limit.

Thanks for the info on the part. Are there any hoses which will change, or will just getting new ones for what the D uses suffice?

[OR75]

 

[OR75]

The thread has info on brackets , hoses, governor settings etc ...

 

[ArtVandelay]

From an engine builder, roller tappets dont help much.
20° timing is stamped on the A3B6 engine, so your kinda of stuck with it.

I already have a A3B6, new from the factory 20 years ago, currently at 2000 hours, will O/H when the time comes.

[carusoam]

When exchanging an old engine as part of getting one back from the factory...

They give some guidance of what they expect in return.  Just make sure to follow along or have a discussion with them about what you are sending back...

The core may have value near 10amu(?).  If they are unhappy with what you are sending back, that could cause some challenges.

plugs, balanced injectors, starters and alternators may be upgrades and you may want to keep them...

Expect that the engine log is the record that they will be using to determine what is on the engine prior to shipping.

Best to have these discussions done and documented prior to buying the new / reman / OH'd engine....

PP thoughts only, not a mechanic...

Best regards,

-a-

Edited May 17, 2017 by carusoam

[Rmag]

16 hours ago, Jeev said:

Do you have the part numbers for the bendix?  I am still running the slicks and would like to switch them out.

I got Bendix put on immediately at my conversion.  The Part numbers in my logbook entry are 10-349305-1 and 10-349365-9

[smccray]

3 hours ago, teejayevans said:

From an engine builder, roller tappets dont help much.
20° timing is stamped on the A3B6 engine, so your kinda of stuck with it.

I already have a A3B6, new from the factory 20 years ago, currently at 2000 hours, will O/H when the time comes.

I noticed Carusoam's mention of 25 degree timing- I'm set at 20% with my A3B6 and it's stamped on the engine.  I googled it... running into a number of old posts on Mooneyspace and other sites.  Interesting discussions about timing- I see my productivity for the afternoon going downhill...

[jetdriven]

7 hours ago, teejayevans said:

From an engine builder, roller tappets dont help much.
20° timing is stamped on the A3B6 engine, so your kinda of stuck with it.

I already have a A3B6, new from the factory 20 years ago, currently at 2000 hours, will O/H when the time comes.

Roller tappets dont help the engine builder pay for his new RV with a new overhaul every 400 hours due to spalled lifters.  Seriously, the biggest risk in these planes besides wing spar corrosion, is the cam and lifter issue. And this board probably has a hundred owners who had to eat a sudden overhaul due to spalling, but not one confirmed early demise of a roller tappet engine.

I have written extensively on how easy it is to get your 25 degrees of timing back, and get Bendix mags in the process, and the cost isnt much either, Slicks sell for big money used.

your A3B6 isnt a roller engine. those began in 2005. They also, mostly, get new cases, which is a relief since they crack so much.

[Jeev]

On 5/16/2017 at 9:55 PM, Jeev said:

I did the same thing about 4 years ago, it was an easy switch and as 201er said was cheaper.  If I remember correctly all I had to do was change the prop governor and the mounting plate for it.  I will take a look at my logs next time I'm at the airport.

Correction, I just looked at my logs and as said above the only thing I had to change was the mounting bracket.  You use the same Gov.

[ArtVandelay]

17 hours ago, jetdriven said:

And this board probably has a hundred owners who had to eat a sudden overhaul due to spalling, but not one confirmed early demise of a roller tappet engine.

The number of owners on this board with new engines with roller tappets probably can be counted on 2 hands, so that's no surprise, let alone those with new engines that are anywhere close to 2000 hours.

[jetdriven]

Theyve been in service since 2005.  Thats 12 years. They're out there, not a majority of the fleet but thousands still.  But find some evidence of ANY lycoming engine with roller tappet failure, regardless of model or brand.  Its a far better technology than flat tappets. Its als not new tech, radial engines from WWII had them.

[Alan Fox]

The single point of failure argument on the dual mag , is just pure stupidity , There are many engines that use the dual mag , most of the 540 turbos use the dmag ,  If you want to talk single point of failure , there is the bolt on the crank , the gear on the crank , the cam gear ,  , The D mag is less expensive to over haul , than 2 singles , and if properly set up . easier to service at annual....

[Rmag]

On 5/17/2017 at 9:36 PM, jetdriven said:

I have written extensively on how easy it is to get your 25 degrees of timing back, and get Bendix mags in the process, and the cost isnt much either, Slicks sell for big money used.

As mentioned earlier, I had my A636D converted to to the A636 specification.  I just so happened to be looking at my data plate today while my right magneto was apart.  My plate is stamped 25° timing.

Is this because of my engine conversion?  Is 25° timing considered a desirable thing vs 20°?