M20J IO-360-A3B6 Conversion Experience

[JCD]

What should I be looking for on new cam and lifters to help prevent this?  Are ther newer materials or surface finishes I should be aware of?

[carusoam]

Use it often is the primary method of avoiding the situation that you have photographed.

1) This keeps the surfaces oiled.  

2) Oiled lifter surfaces avoid oxidation.  

3) non-oxidized surfaces don't pit.

4) there are cams that have improved oil characteristics.  This gets oil to the surfaces quicker after start-up.

5) there are dehydration systems to keep the air inside the engine dry.

There are a few IO360 engines that have seen this challenge.  Often by new owners that bought from somebody that was not using the plane.  The similar in design IO540 and O360 don't seem to suffer as much.

Use the search function to find out more about these details...

PP advice, I'm not a mechanic.

Best regards,

-a-

[Andy95W]

3 hours ago, JCD said:

What should I be looking for on new cam and lifters to help prevent this?  Are ther newer materials or surface finishes I should be aware of?

Roller tappets.  But you're not gonna like the price.

[gsxrpilot]

The best preventative you can buy is 100LL.

[KSMooniac]

Fly regularly and use Camguard.  You can also hook up your engine to a dehydrator rig while it isn't flying to minimize the chance of rust formation.  I haven't done that yet, but am being more diligent since my overhaul to fly every 7-10 days at least.

I opted to overhaul my -A3B6D instead of switching to a factory reman with roller tappets and separate mags.  During the overhaul, I opted to get the Centrilube modification that adds oil passages thru the cam directly to the cam lobes for near-immediate oiling of that interface.  Without, the cam relies on splash oiling from the crank slinging oil off and hoping enough lands on the cam.  I also took the opportunity to get my cylinders flow-matches, and have all of the rotating components balanced to tighter tolerances than the factory provides.  I am not scared of the dual mag so long as it is inspected/serviced every 500 hours, which I do without fail.  Some prefer separate mags and that is fine with me too... I just didn't think it was worth the extra expense and weight to change my plane.  My overhaul was much less expensive than swapping for a factory reman or overhaul, but took much longer so that is the tradeoff.

[aaronk25]

You will never get your money back out of the upgrade. Fix it up and overall it.


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[Hillard]

Dan,

Firstly, thank you for the detailed summary of your experience that you posted in 2015.  I am facing the same decisions due to my A3B6D engine making metal due, we think, to lifters.  I'm thinking of moving to the A3B6 variant and the cost of an exchange factory overhaul is about the same as for the A3B6D.  In trawling the previous posts regarding this changeover, I've heard various reports of the aircraft flying circa 5 knots slower due to the timing of the Slick mags on the A3B6 engine.  In your experience, is this true?  Others have talked about swapping to Bendix mags to get the speed back.  My aircraft does book numbers i.e. 155kts (65% power at 7000') and I'd like to keep it that way.

Whatever way I go, I'm hoping that the roller lifters will perform better than the ones in my existing engine.  It was a factory reman fitted in 2005 and I've done 1400 hours behind it in 11 years with 25 hour oil changes (Shell W100 and camguard) so it cannot be attributed to the engine being idle.  It also had a top overhaul at 800hrs due to a broken ring.  Needless to say, I am not impressed with the quality of Lycoming's product.  

I'm also hoping that it will run on whatever is blessed as the unleaded avgas replacement in 2018!   I'd hoped to continue with my existing engine in the hope of a 200hp diesel engine STC appearing for the 20J, but sadly not.  I'm astounded at how little attention the unleaded avgas issues are getting in the flying press given that he change is likely to be only a couple of years away.  Given the very high octane components required to make avgas spec without lead, it is likely that some refineries won't be able to make it.

If we do decide to run with the A3B6 then thank you again for your post as it will certainly have saved us time and money by alerting us to the issues before we start.  The costs of doing this in Australia are much higher than in the USA (circa $55,000) so I'd like to get this right.

[jetdriven]

If it's a 2005 overhaul it may be a roller engine. 

[Hillard]

Sadly not - it was built just before the change to roller lifters

[OR75]

Another option often forgotten if you are going for a factory reman , is that there is an STC to install an IO-390-A3A6 ( Lycoming accepts the IO-360 as a core )

it gets you to 210HP

cost is high if you don't already have the right prop ( hartzel) 

a few years back , the cost was in my opinion prohibitive but it it may be something worth revisiting . 

[Hillard]

The price that I had for the IO-390 were actually less than for the other variants - except that the dealers weren't able to tell me the additional cost of the STC.  What rules out the Io-390 for me is that I have the McCauley 3 blade prop (that I have just overhauled) and the STC requires that a Hartzell prop be installed.

[KSMooniac]

$4000 390 cylinders is hard to stomach too.

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[OR75]

19 minutes ago, KSMooniac said:

$4000 390 cylinders is hard to stomach too.

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It used to be but I don't think that's the case anymore . The 390 cylinders price is about the same as the 360's now 

[dhc]

To Hillard:

I have not noticed any speed degradation due to the engine replacement. I haven't noticed any speed increase either, however. Without wanting to open up a can of controversy, I'll say that I don't put much stock in contentions of the 25 deg vs 20 deg timing advance making a substantial difference in actual engine output.

I *was* disappointed that my only 2-year old Slick mags both showed excessive points wear. Anecdotal evidence suggests this is common, and conventional wisdom is that replacing with Tempest points will make things better. I replaced them for both mags and now my starts (both cold and hot) are better.

Sorry for the late reply. I seem to only have time to read Mooneyspace while stuck on long commercial flights these days...

Dan

[jetdriven]

I've got plenty of 3-track gps data that shows at all three knobs forward it's around 5 knots but the real crappy situation is trying to fly LOP. It just wouldn't do it without losing 10 knots. 

Replace the slick mags with Bendix 1200s.  I just did the 500-hr inspection on mine. Normal wear. I did the whole inspection but really it only needed a set of points in another 300hr. Those mags are cheaper too. Definitely cheaper to run 1000 hours on. You won't have to buy a new Bendix mag or two in that time frame. 

[aaronk25]

Ah ya second that jetdriven is right on the money. I tried 20 degrees btdc it's exactly as he describes. 5 kts max speed close to 10kts Lop.


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[ArtVandelay]

I've got plenty of 3-track gps data that shows at all three knobs forward it's around 5 knots but the real crappy situation is trying to fly LOP. It just wouldn't do it without losing 10 knots. 
Replace the slick mags with Bendix 1200s.  I just did the 500-hr inspection on mine. Normal wear. I did the whole inspection but really it only needed a set of points in another 300hr. Those mags are cheaper too. Definitely cheaper to run 1000 hours on. You won't have to buy a new Bendix mag or two in that time frame. 

I agree it's harder to run LOP, but 10 knots? Given that drag rises exponentially, that is a huge horsepower decline. I would study your engine monitor data to look for anomalies.
Here is a link debunking the spark advance = more power:
http://www.innovatemotorsports.com/resources/myths.php
It also says timing doesn't change with RPM.
I found the slicks points last about 400 hrs, I will try tempest next time, how long does the Bendix points last?

[jetdriven]

By peak egt the power had fallen off pretty noticeably and by 25 LOP     It was much worse. Leaning past best power is the same effect as retarding timing.  But the lower base timing is also a factor. 

I have a high HP turbo car and I would agree that timing isn't nearly as critical an adjustment for power as on a NA Lycoming running at 65%. I would set the max timing advance to ~15 degrees and run as much boost as I could get away with, often 30 PSI, and make 400 crank HP on 2.0L. The tighter you squeeze it, the faster and harder it burns. At lower boost and certainly at midrange power, 25 degrees of timing was normal. But the non-turbo cars, a couple degrees timing as worth a tenth or two, more as you moved further away from optimal. 5 degrees is a lot. 

Edited August 24, 2017 by jetdriven

[jetdriven]

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. 

Edited August 24, 2017 by jetdriven

[jetdriven]

On 10/8/2016 at 8:26 PM, JCD said:

What should I be looking for on new cam and lifters to help prevent this?  Are ther newer materials or surface finishes I should be aware of?

From Ken at LyCon, the new DLC coated Lycoming factory lifters are the closest thing to indestructible that exists. He basically hasn't seen one spall yet and some are on traffic watch planes with 5000 hours on a set.  This may actually cure it. 

[mike_elliott]

5 minutes ago, jetdriven said:

From Ken at LyCon, the new DLC coated Lycoming factory lifters are the closest thing to indestructible that exists. He basically hasn't seen one spall yet and some are on traffic watch planes with 5000 hours on a set.  This may actually cure it. 

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?

[Bob - S50]

If 20 BTDC is costing power and speed, sounds like a perfect excuse to get electronic ignition.  It advances the timing as the RPM increases and the MP drops.

[ArtVandelay]

If 20 BTDC is costing power and speed, sounds like a perfect excuse to get electronic ignition.  It advances the timing as the RPM increases and the MP drops.

When the time comes to O/H, I'm definitely going with EI.

[aaronk25]

Ya but the EI only fires one plug, sooner. All being equivalent one firing at say 25btdc and one at 20 makes for a delta somewhere in between? Plus isn't it more efficient to have the flame fronts meet each other than have to spread all the way across our coffee can size cylinders which is why both plugs aren't mounted near each other.

Now if EI could ramp up the spark advance on both of the plugs and keep them even that would be sweet!


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[mccdeuce]

I have EI and currently have 20btdc.  I will tell you for the most part it makes zero difference that I only have 1 EI and not both.  The park is so much more powerful that it does 90% of the work.  I get a 20rpm drop securing the mag, and a 200rpm drop when securing the EI.  And my mag produces a very hot spark, its just that the Ei does so much.

That all said - I will be looking at converting my system to 25.  I want the EI to advance to 30 deg at altitude to truly take in the benefits.  Not just advance to 25...