M20J IO-360-A3B6 Conversion Experience

[jclemens]

6 hours ago, mike_elliott said:

hummm....sounds like fixing the effect, not the cause to me. Now that they have hard pointed the lifters, what wears with the current lubrication design?

The rocker arm end of the pushrod, and the rocker arm.  The roller tappet engines do not have round tappets, hence they don't rotate.  They don't rotate, the pushrods don't rotate.  These were removed from a first run factory IO-360 roller tappet engine.  7/8 are junk.  Dry tappet clearance was way out of spec due to the wear.  Engine made TBO though.

[jetdriven]

That's interesting. All the OHV pushrod motors such as the Chevy L98, LS and the 5.0 HO Ford motor also used roller tappets and pushrods and I never saw wear like that. I wonder how they did it. Or is it just not enough oil to the head?

[Guest]

9 hours ago, jetdriven said:

My bendix 1200s had Kelly points and they had 500hr on them. They looked like about 1/2 worn, compared to the new CMI points we replaced them with. So I'd guess 700hr but still, always inspect the mags at 500hr. But i feel they can reliably go 500hr between inspections.  My observation only, but me and the 5 pilots I know that swapped Slicks for Bendix, do not have magneto problems. 

Is the 1200 series magneto approved for the 360 or did you have to get a field approval?

Clarence

[jetdriven]

It's listed in the PC406-1 lycoming parts catalog and the application guide for the mags from CMI. So I just bolted them on. 

[Bob - S50]

I started thinking (dangerous I know) about going from 25 to 20 BTDC timing.  Many have claimed lower power, slower speeds, or higher fuel flow.

However, for those cruising below about 6000', I think you can get some of that power and efficiency back.  Operating the engine at a lower RPM has an effect similar to advancing the timing.  And if someone routinely operates 50 - 100F LOP, running a bit less LOP will have an effect similar to advancing the ignition.  Both will cause the peak pressure to happen closer to TDC.

So, instead of operating at 2500 RPM, 22" of MP, and 50F LOP you could operate at 2300 RPM, 24" of MP, and 20F LOP.  I know, that is the dreaded over-square, but my POH permits it and since I live at sea level, I'm over-square for every takeoff (2700 RPM and 30" MP)  The prop may be less efficient at the lower speed, but then again there will be less friction loss at the lower RPM.  Once you get to the point that you are running WOT, there is noting you can do about the timing other than operating closer to peak EGT.

Just my $.02 worth.

[mccdeuce]

Mine is set for 20deg. I did some experimenting this weekend. 

LOP below 4000 is smooth. I prefer flying between 7-9k.  Not quite smooth LOP up there. GAMI spread is inside .5.

[Bob_Belville]

52 minutes ago, mccdeuce said:

Mine is set for 20deg. I did some experimenting this weekend. 

LOP below 4000 is smooth. I prefer flying between 7-9k.  Not quite smooth LOP up there. GAMI spread is inside .5.

Mark, doesn't your EI change the timing with altitude?

[carusoam]

BobS, I followed your logic, but i think it is Missing something...? (Drawing in somebody to do some math, and where is my East Coast flame front expert guy) 

25°BTDC allows more time for the flame to occur.  Thus improves the conversion of fuel to exhaust. The cost is additional CHT to be managed... (how much more time?)  (parts of seconds)

Slowing the engine rotation also allows more time for the flame to occur. At the cost of 100s fewer flames per minute in each cylinder.  Good efficiency, but not so much for power... (how much more time is available?) (is this on the same scale as 25°)

The advantage of advanced timing is more power when you want it.  Like for T/O and climb...

If your objective is efficiency... 25° and Slowing the rpm and fly along at V (what's that slow efficient air speed called?)

25° timing may not work if you fly around in hot OATs a lot, and CHTs become unmanageable.  Really High CHTs would cost too many cylinders over time making 20° timing the best compromise you can make...

That would be a good paragraph for somebody writing a paper on GA NA engine power...

Thanks, you made me think about this for a while!

Best regards,

-a-

[Bob - S50]

1 hour ago, carusoam said:

Slowing the engine rotation also allows more time for the flame to occur. At the cost of 100s fewer flames per minute in each cylinder.  Good efficiency, but not so much for power... (how much more time is available?) (is this on the same scale as 25°)

The advantage of advanced timing is more power when you want it.  Like for T/O and climb...

True and True.  However, at lower altitudes, by increasing the MP to offset the reduced RPM, more air and fuel for each bang makes each bang bigger and closer to the ideal connecting rod angle.  That should offset the reduced number of bangs.

Any time you are WOT, reducing RPM only hurts.  That would be, as you say, T/O, climb, and higher altitudes.

It was just a thought for those bemoaning their engines being timed at 20 rather than 25 BTDC.  Mine is stuck at 25 because it is a 'D' engine and changing to 20 is not an option.

[ArtVandelay]

Mine is set for 20deg. I did some experimenting this weekend. 
LOP below 4000 is smooth. I prefer flying between 7-9k.  Not quite smooth LOP up there. GAMI spread is inside .5.

Did you try varying the RPM?

[carusoam]

9 hours ago, mccdeuce said:

Mine is set for 20deg. I did some experimenting this weekend. 

LOP below 4000 is smooth. I prefer flying between 7-9k.  Not quite smooth LOP up there. GAMI spread is inside .5.

LOP definitely is a sensitive indicator of how well balanced the fuel injectors are.  And how the spread effects operations at various altitudes...

At low altitudes, a well balanced system can go 90°F LOP before shutting down.

At higher altitudes, the same system may only see 50°F LOP before shutting down.

Not that anyone usually wants to run this far LOP, but it is an indication of how smoothly a low Gami spread can operate.

Taken From experiments I ran when I first got the O...

Best regards,

-a-

 

[mccdeuce]

12 hours ago, Bob_Belville said:

Mark, doesn't your EI change the timing with altitude?

That it does. I would say prob 3-5 degrees. 

But it was this way before I switched to the EI. 

[mccdeuce]

7 hours ago, teejayevans said:

Did you try varying the RPM?

Tried between 2450 and 2550. Still experimenting. 

[Hillard]

Dan,

The install is almost done so I'll let you know how she performs.  I can only repeat our thanks to you for the detailed notes that you provided.  It meant that we could anticipate problems and get the parts in ahead of time.  The install of the throttle bellcrank was not obvious and it took a bit of fiddling before we worked it out.  My aircraft is a 95 model so I suspect that the SB you refer to had been done at the factory - we had to implement the fix that you describe.

We will monitor the points wear on the Slick mags and change them out if need be.

John

[Hillard]

Dan,

I (finally) picked up the plane on Monday and have done 6 hours so far.  Temperatures have stabilised and all seems to be going well.  You'll be amused (but probably not surprised) to know that Lycoming have invented yet another impediment to the fitting of this engine to a Mooney.  We started it ten days ago and everything was fine - except that the fuel pressure gauge was pegged to the right.  We then found that Lycoming now fit a different (and supposedly equivalent) fuel pump to that engine.  A search on Google showed that other people are finding that it actually runs at nearer 35psi - a fact that Lycoming freely admits.  This is a problem if Mooney have a limit of 30psi  as manufacturer limits trump component manufacturer limits.  It appears that there are a number of people in the US right now running their engines under the fiction that their gauge shows 29psi.  The engine importer here recognise the issue and replaced the fuel pump with the old model (at their cost) and, guess what, the fuel pressure is back where it should be.

The one remaining issue is that the prop control is sitting about an inch out from the firewall.  It does not affect practical operations but it does look odd.  Did you find the same and, if so, how did you modify it?

 regards

John

[Mikhail]

Guys, anybody can advise a good mechanic to help with engine conversion in DFW area? 

I'm based in Hicks, T67.

Thanks a lot

[carusoam]

See if @jetdriven has a recommendation ^^^

 

john @Hillard, I recall a thread regarding the high fuel pressure you described seeing here.  Looks like you have an answer.  Not sure if the other thread came to a conclusion...

might have been completely different...  M20C related.

 

Best regards,

-a-

[Mikhail]

On 7/12/2015 at 8:20 PM, dhc said:

06: That new prop governor arm--correct orientation, and how to rig

 

The –A3B6 installation requires a new prop cable rigging arm, which must be purchased from Mooney. These are the P/N’s:

 

• 660017-003 Prop cable clamp half

• 660017-005 Prop cable clamp half

• 660235-001 prop cable bracket

• 660235-003 governor bell-crank

 

And the governing chapter in the Mooney Parts Manual is 76-00-01.

 

The proper installation of these parts is completely opaque: neither the Parts nor Service manual contain any drawings to provide proper guidance. Worse, on Mooneyspace, there is an often-cited post with an ABSOLUTELY WRONG installation of the both the bracket and the governor bell-crank.

 

I am including both the wrong photos (properly annotated) and correct ones in this post. Note:

1. The proper orientation of the cable bracket relative to the engine
2. The proper layout of the two clamp halves (“thin one on top”)
3. The proper position of the prop cable metal collar in the clamp halves

Proper rigging also requires that full prop speed be attained with cable all the way in (with sufficient “cushion”), and the degree of freedom used here for this model of prop governor (McCauley DC290D1-F/T22) is that the center part of the assembly rotates freely when the 6 allen head screws are loosened. Since the position of the center part is at an arbitrary clock angle when the unit is newly acquired, it is good to scribe the final rigged clock angle for future use, as the photo shows.

 

 

Guys please advise ,

we have installed governor and now couldn’t figure out how to install a small bracket that doesn’t feet to the arm.... seems like a governor arm is flip over...?

enclising picture here...

Any advise?

Thanks !

Mikhail

[Oldguy]

@Mikhail from just a casual observers point of view, you look to have it mounted correctly. From the last picture from @dhc's post you included, the cable attaches to the the end of the arm that is not on the end of the arm mounted on the governor.

The new, thin arm attaches to the governor arm with a bolt, and the cable attaches to the other end. When you then pull the cable in the cockpit, it moves the governor arm counter-clockwise away from the stop where it currently rests.

You have it mounted correctly, but just need to finish it up.

Having said all that, please see my first few words - not a airplane mechanic - but I have turned a wrench a few times on other vehicles.

[Mikhail]

9 hours ago, Oldguy said:

@Mikhail from just a casual observers point of view, you look to have it mounted correctly. From the last picture from @dhc's post you included, the cable attaches to the the end of the arm that is not on the end of the arm mounted on the governor.

The new, thin arm attaches to the governor arm with a bolt, and the cable attaches to the other end. When you then pull the cable in the cockpit, it moves the governor arm counter-clockwise away from the stop where it currently rests.

You have it mounted correctly, but just need to finish it up.

Having said all that, please see my first few words - not a airplane mechanic - but I have turned a wrench a few times on other vehicles.

Thanks Oldguy but the only way how now the small bracket is fit  it’s like that (picture).

Im confused how I will attached the cable in this case?

thanks

[Oldguy]

Okay, let's look at my poorly marked up drawing.

IMPORTANT NOTE: I just noticed you have the bracket upside down in your picture. Turn it over so the "ledge" is on the bottom. Not sure it makes a difference, but it matches up with @dhc's picture above. But my lettering does not change, i.e."A" is still on the left and "B" is still on the right.

A - bolt holding governor arm to new small bracket.

B - (from front of new small bracket to behind it) castellated nut with cotter key, bracket, spacer, prop governor cable end, bolt going through everything and held on with nut and cotter key.

C & D - location of bolts holding these two parts to the large arm - be sure to note the thicker one is located against the arm.

• 660017-003 Prop cable clamp half

• 660017-005 Prop cable clamp half

Yellow line is a routing of governor cable. Note it will end behind the small bracket. See picture following my "B" above. The clamps bolted into C & D hold the upper part of the cable in place.

Let me know if you have any more questions. Be glad to help if I can.

Edited September 11, 2018 by Oldguy
Added NOTE.

[Hillard]

Mikhail,

You are not alone.  When we fitted it in Nov 2017, my A&P spent quite a few hours figuring this out. 

What has been your experience with the two traps (referred to elsewhere in this thread) that Lycoming set for us in doing this installation?:

a) the prop oil line supplied with the engine from the factory cannot be installed due to interference with the engine mount;

b) the different fuel pump now supplied with the engine (and supposedly equivalent) puts out a pressure higher than the 30psi limit imposed by Mooney.

I'm interested to see whether Lycoming have made any effort to address these issues that have been raised with them in recent years.

 

[Mikhail]

On 9/11/2018 at 5:41 PM, Hillard said:

Mikhail,

You are not alone.  When we fitted it in Nov 2017, my A&P spent quite a few hours figuring this out. 

What has been your experience with the two traps (referred to elsewhere in this thread) that Lycoming set for us in doing this installation?:

a) the prop oil line supplied with the engine from the factory cannot be installed due to interference with the engine mount;

b) the different fuel pump now supplied with the engine (and supposedly equivalent) puts out a pressure higher than the 30psi limit imposed by Mooney.

I'm interested to see whether Lycoming have made any effort to address these issues that have been raised with them in recent years.

 

I have to buy a new oil line from AVAIL..

And for fuel pump I’m far to check it the pressure but right now I’m looking how to connect the hose to fuel servo because the output from the pump looking right to the firewall......

 

[Mikhail]

On 9/11/2018 at 8:20 AM, Oldguy said:

Okay, let's look at my poorly marked up drawing.

IMPORTANT NOTE: I just noticed you have the bracket upside down in your picture. Turn it over so the "ledge" is on the bottom. Not sure it makes a difference, but it matches up with @dhc's picture above. But my lettering does not change, i.e."A" is still on the left and "B" is still on the right.

A - bolt holding governor arm to new small bracket.

B - (from front of new small bracket to behind it) castellated nut with cotter key, bracket, spacer, prop governor cable end, bolt going through everything and held on with nut and cotter key.

C & D - location of bolts holding these two parts to the large arm - be sure to note the thicker one is located against the arm.

• 660017-003 Prop cable clamp half

• 660017-005 Prop cable clamp half

Yellow line is a routing of governor cable. Note it will end behind the small bracket. See picture following my "B" above. The clamps bolted into C & D hold the upper part of the cable in place.

Let me know if you have any more questions. Be glad to help if I can.

Thanks Oldguy, finally governor installed with bracket, and new cable is connected to the arm....

[PT20J]

I just completed installing an IO-360-A3B6 replacing the A3B6D on my '94 M20J. I have nothing against the dual mag engine and flew happily and uneventfully behind one in a '78 M20J for many years. But I bought the '94 with a run out engine and after talking to Lycoming and top-rated magneto shops, I decided to get a factory rebuilt A3B6. The factory rebuilt part of the decision was mainly to get the roller tappets. The move away from the dual mag was because it turns out there are a lot of differences between an A3B6 and an A3B6D -- even the crankshaft is different. The dual mag IO-360 never really took off and over time, parts are likely going to get more expensive than for the more common single mag version. Lycoming backs this up with money - I got a discount for turning in a A3B6D core for an A3B6. 

The conversion is relatively simple and really well addressed at the beginning of this thread, so I will only address a few areas of confusion.

The biggest area of confusion is the prop governor. You need a McCauley DC290D1/T22. I did an exchange with Dan at West Coast Governor Service. Dan is very knowledgeable and helpful and I highly recommend him. Procure the Mooney brackets listed elsewhere in this thread and also listed in the Mooney Illustrated Parts Catalog (IPC). Mount the governor and brackets before installing the engine -- there is minimal space between the governor and the firewall. To mount the cable bracket, you have to remove three screws from the back of the governor, add the bracket and replace the screws. Do not remove all the screws or the governor will come apart. The  governor control arm can have the clamp screw in one of two orientations and this seems to cause confusion. The Mooney bellcrank is symmetrical and can fit either governor arm. Just flip it around to clear the screw. The bellcrank tab goes against the governor control arm side that has the protruding screw head. This sounds confusing, but it is pretty obvious when you have the parts in your hand. You'll need a longer AN3 bolt and spacer to attach the prop cable rod end to the bellcrank. You can make these up with shop parts or get the parts listed in the IPC. Once mounted and connected you will probably have to reclock the control arm to get the proper prop control movement. The prop control needs to be able to reach the high speed stop on the governor with some cushion before hitting the instrument panel per the Mooney Service Manual. To properly adjust the control arm DO NOT loosen the clamp screw and rotate the arm. This will mess up the internal governor settings. Instead, loosen the 6 screws on the back of the governor and rotate the whole control arm assembly as required and then tighten the screws.

The next area of confusion concerns the prop governor oil line. The line supplied with the A3B6 will interfere with the lower right engine mount. There are three solutions. Lycoming has a different line for Mooneys. It is listed in the Lycoming parts catalog for the engine. No MSC I talked to has ever used it. The Lycoming field rep I discussed it with doesn't recall anyone ever ordering it. It costs several hundred dollars and Lycoming doesn't stock it, so it takes a few weeks to get. This is not your best option. The second option is that Lycoming SI 1435 permits the use of a flexible hose in place of the rigid line. The third and best solution -- used by every MSC mechanic I discussed it with -- is to just bend the line slightly to avoid the interference. My mechanic did this with some difficulty -- it's a stainless steel line and not easy to bend without damaging it -- but with some gentle coaxing he got it to fit acceptably.

The hoses were pretty straightforward -- all the proper lengths are listed in the Mooney IPC. What isn't obvious is that the oil cooler needs to be rotated 180 degrees to that the fittings are on the outside away from the engine. (Thanks to Don Maxwell for pointing that out).

The restrictor fitting for the oil pressure transducer on the A3B6D is a right angle and this needs to be changed to a straight one (610013-511) for clearance purposes on the A3B6. 

If you are reusing your baffles, get new seals from Guy Ginby @ GeeBee (800-556-3160). They're the best.