FFS. I need a new hobby.

cowman said:
On the dual-mag issue I've looked at it too. I think just about everyone looks at the design and says WTF were they thinking. OTOH do the actual stats support the idea that there's a notably higher failure rate with these mags? I haven't seen any good evidence to support that- obviously at one time Lycoming thought it would be just fine. Is this a case of it just not looking good but not actually being a problem in practice?
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Bell206 said:
Many years ago, I was told it was simply based on failure modes. Mechanical drive gear failures were basically nonexistent and if there was a drive failure it usually took out other drive gears that didn't require any redundancy. The electrical side was another matter.
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Odd... The only mags I've had fail were from the gears, and I was told it's quite common here in the colder regions. In the winter especially, the nylon gears get heated way up every flight and then get really cold again, and it makes them brittle, and teeth and whole gears fail.

Does the dual mag use metal gears or something, or would it be susceptible to this sort of failure as well?
 
nrpetersen said:
Jim - do you have a picture of the end of the camshaft?
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Not yet. I'm this far:

IMG_20241025_153243961_HDR.jpg

Spent a couple hours building a wooden workbench to hold it. Something I could walk around and is a little more of a comfortable working height. Got my bags and my note cards and my micrometers and my dial indicators and bore gauges. Armed with an updated Lycoming direct drive overhaul manual. Just need to work up the nerve to turn that first screw...
 
SoonerAviator said:
Send the current oil off to Blackstone for oil analysis and see what comes up. I'm wondering if because your engine has had unit averages for Iron near 46-48 at points in the past, it doesn't raise alarms despite being above universal averages. Also not sure if their universal averages are specific to your engine model or all piston-GA models. It would be interesting to know what data set it uses to show the universal averages.
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Lead is also over - so I question looking only at iron in hindsight wondering if the number is related to things thing that occured, while ignoring all the other variances in the sample. This is kind of classic confirmation bias.
 
bentmettle said:
Lead is also over - so I question looking only at iron in hindsight wondering if the number is related to things thing that occured, while ignoring all the other variances in the sample. This is kind of classic confirmation bias.
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Iirc on once of my early reports, the analyst mentioned my lead being higher due to the averages being based on a 40hr run. The 25 hour people are bringing the average down. Iron might be the same issue.
 
flyingcheesehead said:
Does the dual mag use metal gears or something, or would it be susceptible to this sort of failure as well?
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The gears I'm referring to are the drive gears in the accessory case, not the internal distributor/spur gears. The issue some brought up was the single drive gear side. However, usually if there is an accessory gear failure it tends to take out the other systems drive gears. So the idea was given the low drive gear fail rate, only the electrical side needed to have redundancy which was where the majority of mag failures are to include those nylon distributor gear failures. Regardless, I believe Lycoming discontinued the use of single drive, dual-mags only because their supplier quite producing them and not due to overall failure rates. If you took care of them they were a solid mag.
 
I actually looked up how far away you were. I am *REALLY* good at tearing things apart.

Fortunately you've got a book to tell you how to put it back together :p
 
bentmettle said:
I actually looked up how far away you were. I am *REALLY* good at tearing things apart.

Fortunately you've got a book to tell you how to put it back together :p
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I think we need a work party at Jim’s place. But, no beer until the engine is back together! If each of us takes a cylinder, we’ll have her apart and back together in no time!
 
Racerx said:
It's still beautiful... Are you going full overhaul?
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TBD. I'm leaning towards doing it. I need to get a handle on how much time and cost that's going to add, as well as what shape the engine is in now.
 
The tractor is the correct color.
Jim K said:
Not yet. I'm this far:

View attachment 134576

Spent a couple hours building a wooden workbench to hold it. Something I could walk around and is a little more of a comfortable working height. Got my bags and my note cards and my micrometers and my dial indicators and bore gauges. Armed with an updated Lycoming direct drive overhaul manual. Just need to work up the nerve to turn that first screw...
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Tape over or plug those holes with rags to keep insects and other undesirables out. Even wind blown dirt.
 
farmrjohn said:
The tractor is the correct color
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It's been pretty good. I have a little green and a little red. If you look close at the filthy mirror, you can see that i also have the correct color combine ;)

Made some progress this evening. Bad news is that I don't have a 5-6" micrometer, and my 1-2" only reads thousandths whereas the piston pin specs are in the ten thousandths. Going to have to buy or borrow a couple micrometers. It's been a while since I've done anything to this level of precision.

Using crude, half ass measures like dial calipers (don't judge me... I'll do it right later...) and guestimating between hash marks on the mic, everything Ive measured so far has been within factory limits.

IMG_20241025_220517648.jpg
 
Jim K said:
It's been pretty good. I have a little green and a little red. If you look close at the filthy mirror, you can see that i also have the correct color combine ;)

Made some progress this evening. Bad news is that I don't have a 5-6" micrometer, and my 1-2" only reads thousandths whereas the piston pin specs are in the ten thousandths. Going to have to buy or borrow a couple micrometers. It's been a while since I've done anything to this level of precision.

Using crude, half ass measures like dial calipers (don't judge me... I'll do it right later...) and guestimating between hash marks on the mic, everything Ive measured so far has been within factory limits.

View attachment 134580
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Looks like you worked up the nerve. :)
 
If you are going through all this trouble, make sure your micros are calibrated and/or have gage blocks on hand.

I also write the measurements down for future reference though that does not seem to be all that common.
 
Steamflyer said:
If you are going through all this trouble, make sure your micros are calibrated and/or have gage blocks on hand.

I also write the measurements down for future reference though that does not seem to be all that common.
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I intend to write down every measurement i take whether I make it an overhaul or not. If not, it will show what kind of shape the engine is in, and if we do the full overhaul, having the measurements will add legitimacy to a field overhaul signed off by a random mechanic.
 
geezer said:
Tape over or plug those holes with rags to keep insects and other undesirables out. Even wind blown dirt.
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I got fancy on my trials motorcycle and 3d printed block off plates and plugs for the various orifices during a rebuild.
4 pack of some Plano organizers also let me go fully absurd in a way cardboard can’t.
 
I never use rags or towels around engine builds. Especially red shop rags that you see in many garages including mine.
Parts cleaner(mineral spirits) and air gets used to clean and inspect parts.
I used wood to block off openings after the engine was built waiting to be used.
 
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Gary Ward said:
I never use rags or towels around engine builds. Especially red shop rags that you see in many garages including mine….
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Most folks would be surprised where red rags show up after work’s been done. Strangest place I saw was in the centerline fuel transfer valve of an E-3. Discovered about 3 sorties/20 hours after coming out of a phase inspection.
 
TCABM said:
Most folks would be surprised where red rags show up after work’s been done. Strangest place I saw was in the centerline fuel transfer valve of an E-3. Discovered about 3 sorties/20 hours after coming out of a phase inspection.
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When I built my RV-6, I used red shop towels to clean the tanks, my hands, etc. during the assembly/sealing process. After the first few hours on the airplane, I was shocked at how much red lint was in the gascolator screen. Based on that, I'm not using 'em anywhere near an engine or fuel system in the future...
 
Theyre cheap for a reason. I like old t-shirts as rags. Most of the lint has already been shed into my dryer screen.
 
Closing in on it. Moving slow trying not to damage anything. I've actually got the cases separated about 1/4" since I took this. Kind of a nerve wracking process.

I spent a lot of time checking dimensions in the accessory case this afternoon. Pretty much everything measured on the tight side of new spec. Just had dinner; heading back out to finish splitting it.

IMG_20241026_170204352.jpg
 
Did you use Lycoming's case splitting tool (or a homemade version)? If not, how'd you split it?
 
kyleb said:
Did you use Lycoming's case splitting tool (or a homemade version)? If not, how'd you split it?
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Shop lent me theirs, which itself is a homemade version. Also one side is made for a 4 cylinder, and the other side a six, but there's only 8 bolts. Did I mention they don't do engine work? It was a bit fiddly moving bolts and plates around to move it evenly, but i got it done. I'm thinking I might make my own based on their design. I think all their engine tools date from when the U of I closed their A&P program 15(?) years ago. Since then, some of them have walked off or been repurposed.
 
Jim K said:
…I spent a lot of time checking dimensions in the accessory case this afternoon. Pretty much everything measured on the tight side of new spec.
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Don’t you have a different case on the way? Curious what the plan is.
 
I hope you're logging all this in case you want your a&p.

Also... I think you found your new hobby
 
TCABM said:
Don’t you have a different case on the way? Curious what the plan is.
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New crank cases. Will reuse the old accessory case & gears, so I was measuring all that stuff up. Of course, later I realized that all the gear backlash measurements i took will have to be redone, as the gear shafts mount on the back of the crankcase.

Leaning towards doing all the requirements to be able to call it a major overhaul. Need to talk to a couple machine shops Monday to see what their turn time would be. Wear seems to be pretty non existent, so it'll mainly be just NDT and the required parts. My primary goal is to get back in the air in 2024.

Racerx said:
I hope you're logging all this in case you want your a&p
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Been thinking a lot about that. I decided a couple years ago not to bother because 4800 hours seems like such an impossible goal. This project will be a couple hundred on its own though by the time I count research. I think I'm going to start tracking, as well as go back through my logbook and add up oil changes and whatnot.

My mechanic is complaining about needing more guys...i wonder if I could talk him into a winter side gig...
 
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