Jump to content

M20J IO-360 cam wiped, besides a reman, what else to change in the meantime?


jkarch

Recommended Posts

I had a thread going on for a few months back in December/January where my EGTs in the front two cylinders were about 80-90F lower than the rear ones, and I suspected the cam (via John Paul of GAMI) but hoped it was a flow divider and fuel line issue.  Turns out, while the engine ran reasonably well, the 1&2 intake lobes were wiped.  I only found this because the #2 cylinder started leaking oil out of the bolts (and so did the #3 in the rear, which is odd).  Fast forward 10 minutes after the cylinder pull:  Ok Cam's wiped, but I suspected that already.  I want a Lycoming Rebuilt IO-360 with two mags and roller tappets to replace the A3B6D.  So, with budget limitations, what do I replace / overhaul?

(1) Get a new dry air vacuum pump? It probably has 1000 hours on it and I want to keep doing IFR.  I do have a standby vac system.

(2) Remove air oil separator system? Do I still need this thing with a factory refurbished engine?

(3) Governor's working fine, should I overhaul it?  I've found small amounts of metal in the oil filter, but not too much yet.

(4) Prop has about 800 hours since overhaul, no grease coming out of prop: reseal it?

(5) Lastly, with a cam wiped engine, I was getting 150ish kts out of it, what should I expect from a J at 7500 feet and 2500 RPMs with full MP at standard temperature/pressure, say a standard fall day.

(6) New engine mounts?

 

Also looks like some mods were needed with the starter adapter or something to convert the A3B6D to the A3B6.

Link to comment
Share on other sites

1 hour ago, ArtVandelay said:

Definitely expect more power.
I overhauled prop and governor. Just flushed oil cooler and separator. I also bought new control cables, new alternator, new engine mounts, new heater hoses.
Repainted engine frame, cleaned up firewall, put in new camlocs.



Tom

Thanks Tom, that's very helpful!  Yeah I want to make sure everything is cleaned up to minimize metal FOD in the engine! How much did your cruise speed or climb performance increase on average?

Link to comment
Share on other sites

Sorry about your cam! Tough sell to keep investing in a vac system when there are relatively cheap paths to removing it entirely now and have minimal maintenance costs.  Definitely yes on relatively low cost items that wear out and are much easier to swap when the engine is out:  e.g. engine mounts,  throttle/prop/mixture cables.

  • Thanks 1
Link to comment
Share on other sites

7 hours ago, DXB said:

Sorry about your cam! Tough sell to keep investing in a vac system when there are relatively cheap paths to removing it entirely now and have minimal maintenance costs.  Definitely yes on relatively low cost items that wear out and are much easier to swap when the engine is out:  e.g. engine mounts,  throttle/prop/mixture cables.

Wow, I remember paying almost $800 for a mixture cable like 6 years ago!  I think that one's still good :)  Throttle and prop cables maybe though...

Link to comment
Share on other sites

Thanks Tom, that's very helpful!  Yeah I want to make sure everything is cleaned up to minimize metal FOD in the engine! How much did your cruise speed or climb performance increase on average?

Alot, at the end I was 15+ below book. I noticed it on first takeoff, before I left the ground.


Tom
Link to comment
Share on other sites

Wow, I remember paying almost $800 for a mixture cable like 6 years ago!  I think that one's still good   Throttle and prop cables maybe though...

I thought the mixture was the cheaper cable, and the throttle was expensive? I think all 3 came in around 1 amu, After paying all the bills (Engine, prop, parts, and AP) I went into shock and can’t remember details. Mine were 40 years old so it was a no brainer.


Tom
  • Like 1
Link to comment
Share on other sites

Jkarch

I think you may also need a revised prop governor bracket. Better to be advised than surprised.

i did not see mention of the cowl baffling. Strongly recommended throwing a ball in the air on the forum ... regarding researching your option on best baffle options.

  • Thanks 1
Link to comment
Share on other sites

1. Ref. Vacuum pump, assuming it is a dry pump, you are at about 2x borrowed time.  If you fly IFR, I would suggest changing it while convenient.  The trauma of the engine change alone may make it decide to go.

2. Air oil separator is nearly like the discussion on LOP/ROP.  Will keep the belly cleaner, but some may argue it caused your cam problem to begin with.  I don’t know the answer.  I have one on my mid time engine, but will kick myself if I have cam problems.

3.  Were you doing oil analysis?  Was there any indication metal was caused by governor?  Perhaps do what Doc said and flush, but filter the first round of discharge to see if anything comes out in the form of metal.

4.  Cody is a good resource on props.  If not leaking and low time, maybe save money here.

5.  Hope you get more speed.  160 would be nice for a well rigged J.

6. Yes...best time to replace is when engine is off....

  • Thanks 1
Link to comment
Share on other sites

Jkarch I think you may also need a revised prop governor bracket. Better to be advised than surprised.

i did not see mention of the cowl baffling. Strongly recommended throwing a ball in the air on the forum ... regarding researching your option on best baffle options.

 

I believe there is a service bulletin describing what needs to be done when switching to A3B6 engine. Prop bracket is one, maybe other minor mods required.

 My prop governor was too old (non serviceable parts I think the guy said), so they replaced with another freshly overhauled one.

 

Tom

 

  • Thanks 1
Link to comment
Share on other sites

@jkarch, here is a very detailed thread on a change from an A3B6D to an A3B6 with tons of information, part numbers, and "gotchas" from someone who did it a couple of years ago. I have it tagged to use when I do the swap on mine, if and when I need a new engine.

 

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

I went with Aero Engines of Winchester for my overhaul because of Lycoming’s lead times. Added bonus was they used parts from superior so I wasn’t subject to the required teardown that all Lycoming factory overhauls from that time needed due to the potential that rod bushings were out of spec. 

I had all of my wiring for the alternator and power replaced when they did my engine. Those wires fail from vibration more often than alternators fail and can cause you to have an AOG situation (happened 3x to me before replacing them and to many other MS members). No need to overhaul your prop and governor, just have them IRAN it. Make sure your governor bracket is included and let the prop shop install it so your IA doesnt damage the seal. 

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

11 hours ago, Oldguy said:

@jkarch, here is a very detailed thread on a change from an A3B6D to an A3B6 with tons of information, part numbers, and "gotchas" from someone who did it a couple of years ago. I have it tagged to use when I do the swap on mine, if and when I need a new engine.

 

Oldguy this is extremely useful!  Much appreciated!  I called Dan at Lake Aero in CA and he's looking into engine options including getting the correct oil line, governor mounts and a bunch of other things like properly sized oil and fuel lines. He's looking into a kit for me now.It's very much a pain in the butt. I think lead time could prove to be a problem since Lycoming is shutting down for a week in June too.

Link to comment
Share on other sites

11 hours ago, FloridaMan said:

I went with Aero Engines of Winchester for my overhaul because of Lycoming’s lead times. Added bonus was they used parts from superior so I wasn’t subject to the required teardown that all Lycoming factory overhauls from that time needed due to the potential that rod bushings were out of spec. 

I had all of my wiring for the alternator and power replaced when they did my engine. Those wires fail from vibration more often than alternators fail and can cause you to have an AOG situation (happened 3x to me before replacing them and to many other MS members). No need to overhaul your prop and governor, just have them IRAN it. Make sure your governor bracket is included and let the prop shop install it so your IA doesnt damage the seal. 

Yeah the Lycoming Lead time seems a bit nuts.It may be almost three months.  Wow.  But I'd assume then my Factory Reman might be closer to a new engine because they have to make all the parts...Good to know about the wiring concerns. I'll have to check.  Looks like the governor can be IRANed but has to be reset for the A3B6 model with a different gear ratio...  Thank you!

Link to comment
Share on other sites

14 hours ago, takair said:

1. Ref. Vacuum pump, assuming it is a dry pump, you are at about 2x borrowed time.  If you fly IFR, I would suggest changing it while convenient.  The trauma of the engine change alone may make it decide to go.

2. Air oil separator is nearly like the discussion on LOP/ROP.  Will keep the belly cleaner, but some may argue it caused your cam problem to begin with.  I don’t know the answer.  I have one on my mid time engine, but will kick myself if I have cam problems.

3.  Were you doing oil analysis?  Was there any indication metal was caused by governor?  Perhaps do what Doc said and flush, but filter the first round of discharge to see if anything comes out in the form of metal.

4.  Cody is a good resource on props.  If not leaking and low time, maybe save money here.

5.  Hope you get more speed.  160 would be nice for a well rigged J.

6. Yes...best time to replace is when engine is off....

Thanks Takair.  Oil analysis interestingly showed no signs, the sign that I was tuned into was the fact that the UBG 16 bar graph showed #1 and #2  peaking much later (1+GPH) than 3 and 4.  John Paul of GAMI suggested it because the GAMIjectors never got the flows any closer, but the cam wipe took a really long time. I must have added GAMIs 3 years ago because the engine ran a bit rough in flight.  That smoothed it out but never fixed the fuel flow peak issue. At pulling it ran smoothly, just not as strong as I remember it.  Only reason it's been pulled is it developed an oil leak out of one of the pins joining the two cases together, so we pulled the cylinder to inspect.  I saw it coming, but three mechanics said fly it until the metal gets bad.  Well once it was opened for this issue it was too late. I figure the prop can get cleaned, but the governor needs an IRAN and a retune for the new engine gear ratio.

Link to comment
Share on other sites

17 hours ago, M20JFlyer said:

Jkarch

I think you may also need a revised prop governor bracket. Better to be advised than surprised.

i did not see mention of the cowl baffling. Strongly recommended throwing a ball in the air on the forum ... regarding researching your option on best baffle options.

Interesting-- seems like my baffling was actually pretty good.  I always had decent cooling, except on hot days where I had to fly with cowl flaps in trail.  Any reason to replace good baffling?

Link to comment
Share on other sites

17 hours ago, ArtVandelay said:


I thought the mixture was the cheaper cable, and the throttle was expensive? I think all 3 came in around 1 amu, After paying all the bills (Engine, prop, parts, and AP) I went into shock and can’t remember details. Mine were 40 years old so it was a no brainer.


Tom

I remember paying like $800 for the mixture cable, and it took almost a month to get it from Mooney!

Link to comment
Share on other sites

2 minutes ago, jkarch said:

I remember paying like $800 for the mixture cable, and it took almost a month to get it from Mooney!

Check out McFarlane.  There are a couple of threads with info. They were under $400 if I recall.

  • Thanks 1
Link to comment
Share on other sites

You need to flush, at a minimum, (dissasemble and reseal) the prop and governor, and flush the oil cooler and replace the hoses if not very old, definately flush if not replacing. Your Lycoming engine warranty depends on that, they specifically call that out.

Edited by jetdriven
  • Like 1
Link to comment
Share on other sites

1 hour ago, jetdriven said:

You need to flush, at a minimum, (dissasemble and reseal) the prop and governor, and flush the oil cooler and replace the hoses if not very old, definately flush if not replacing. Your Lycoming engine warranty depends on that, they specifically call that out.

Byron, I appreciate that.  I will make sure everything gets done, IRAN /clean at the minimum.  I'm trying also to see if I can get the ElectroAir added to one mag while I'm at it too.  But then another idea comes to mine.  What is a timed out M20J with 2500 hours on the airframe worth with a GTN 750, GDL-88, and Flightstream 210? 85K?  I wonder if it might make sense to go to a 231 from here, because I spend most of my time climbing above 10K ft. I like flying around Mt. Rainier at 17K with O2, and while I could usually get up there within 25 minutes or so in winter, the summer performance usually keeps me around 15 when I'm crossing the Cascades and Rockies.  Seems like for 130K, which is what the plane might be worth with a fresh engine, I could get an equally nice 231 with a fresh engine, maybe with a 430W instead. Makes me wonder if it's better to let someone else do this, and jump on a turbo instead...  But the roller lifters and good fuel economy does sound nice. Plus I've already done WeepNoMore on one tank and the other is still in good shape, and added fresh donuts recently, so it would be a shame to give it up with everything I've done to it.

Link to comment
Share on other sites

If you get a rebuilt from Lycoming, you get the roller tappets which I think is a big plus. All the radials had them and they don’t seem to suffer tappet or cam gear failures. The dual mag is getting expensive to maintain due to parts availability, lack of factory support and the fact that only a few mag shops will work on them. I decided to get an A3B6 and dump the dual mag. 

The threads on MS have the details you’ll want to know about if you change engines. The Mooney IPC lists the parts you need but there are no drawings. There are a few tricky things like figuring out how to properly rig the prop governor and you need to flip the oil cooler around 180 degrees. The A3B6 uses a different governor than the A3B6D, so it will need to be modified and overhauled or exchanged. It’s also a good idea to get the oil cooler overhauled - it’s not expensive. 

The Lycoming parts catalog lists a Mooney prop governor line but they refused to ship the engine with that line installed, and it’s several hundred dollars and several weeks to get them to make one. Most shops just bend the standard line slightly to clear the engine mount. That’s what we did. 

Lycoming ships the rebuilts with an alternator, but no starter. 

Don Maxwell has done several A3B6D to A3B6 conversions and is a good resource.

Skip

  • Thanks 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.