Looking to “Borrow” an IO-360-A3B6D Case

[RoundTwo]

I’ve got a pretty significant oil leak coming out between the nut and through bolt on my number three cylinder, and the most likely culprit is either a cracked web on the case or simply fretting on the pads. Because of the significant downtime related to splitting the case, and sending it out for work, I’m hoping to shorten that timeframe by finding a donor case to either buy or borrow and replace that with my case after tear down.

I realize this is a rather unorthodox method of doing this, but if I can’t get the case work done before the engine comes out of the plane, I’m looking at a six months of being grounded.

Can anyone suggest any other creative options to get this done without being down for such a long period of time?

Thanks,

Chuck

[N201MKTurbo]

You can replace the through bolt with an oversized through bolt without splitting the cases. Doing so will probably fix your leak. There is a Lycoming service bulletin about the process.

It can be done without removing the engine from the plane. You will need to remove two cylinders.

[RoundTwo]

24 minutes ago, N201MKTurbo said:

You can replace the through bolt with an oversized through bolt without splitting the cases. Doing so will probably fix your leak. There is a Lycoming service bulletin about the process.

It can be done without removing the engine from the plane. You will need to remove two cylinders.

Is that a P1 bolt you’re referring to? my concern with just targeting the leak, is there is an underlying reason why it’s leaking, and I would be concerned that Band-Aid the oil leak is ignoring the root cause which might actually be a safety related issue if it were a crack or fretting on the case pads. At this point I’m trying to educate myself on all aspects. All input is appreciated.

[Ragsf15e]

Has the case been split previously?  Have the cylinders been replaced recently?

[mike_elliott]

You can clean it completely then check with magnaflux powder applied to the suspecting area. Run it hard for a bit, then check. A crack will be apparent if cracked. The leak source will be apparent. A poor man's ver of magnaflux is spray foot powder.

 

[A64Pilot]

4 minutes ago, mike_elliott said:

You can clean it completely then check with magnaflux powder applied to the suspecting area. Run it hard for a bit, then check. A crack will be apparent if cracked. The leak source will be apparent. A poor man's ver of magnaflux is spray foot powder.

 

You can even use flour or tire talc, just “dust” it on, a paint brush works.

Usually if it’s a crack after cleaning the case well the dry powder will pull the oil out of the crack just like it does dye penetrant, often you don’t even have to run the motor again.

I’m chasing oil leaks on a C-85 right now. Current leak seems to be right at the base of the oil tank

[N201MKTurbo]

18 minutes ago, RoundTwo said:

Is that a P1 bolt you’re referring to? my concern with just targeting the leak, is there is an underlying reason why it’s leaking, and I would be concerned that Band-Aid the oil leak is ignoring the root cause which might actually be a safety related issue if it were a crack or fretting on the case pads. At this point I’m trying to educate myself on all aspects. All input is appreciated.

It isn’t a band aid fix. If you had the cases overhauled, and it was leaking at the through bolt, the case overhauler would put an oversized through bolt in. I believe they require you to stamp the oversized value near the bolt on the cylinder flange.

[RoundTwo]

1 hour ago, Ragsf15e said:

Has the case been split previously?  Have the cylinders been replaced recently?

The case has never been split, but cylinders replaced 12 years ago.

[RoundTwo]

2 hours ago, mike_elliott said:

You can clean it completely then check with magnaflux powder applied to the suspecting area. Run it hard for a bit, then check. A crack will be apparent if cracked. The leak source will be apparent. A poor man's ver of magnaflux is spray foot powder.

 

Here are a couple pictures to illustrate the severity of the leak. One shows a drip formed after about 5 minutes of idling. The other is a paper towel I rolled up and wedged in under the fuel line running up to the spider. It soaked up this much oil in 11 flight hours. 

[Ragsf15e]

Personally, I think I’d talk to a few engine shops about the leak and the procedure @N201MKTurbo recommended and then pick a shop to fly it to do that.  Probably not even remove it from the airplane.  

I had a little seepage at tge same spot after cylinder replacement but my mechanic told me to relax and it does seem to have stopped which is why I asked, but your cylinder work was a long time ago.

[N201MKTurbo]

You want Lycoming Service Instruction 1290F. It is titled "Crankcase Thru-Stud Locations, Repair of Oil Leakage, Assembled and Unassembled Engines"

 

[Shadrach]

@RoundTwo

Unless all of the shops that are local to you are really backed up, borrowing a case is not going to save you much time. It took me ~6 hours to remove my engine from the airframe and then remove all accessories. I dropped the engine at my engine shop late morning, and they had the case halves crated and shipped by 4:30 that afternoon. Shipping, Overhaul and Assembly will take more time.

All of the above being said, Lycoming SI 1290F (requires a subscription to view) was released for a reason. Without evidence that the leak is from a case crack, it would be prudent to pursue the least invasive repair.

 

[RoundTwo]

9 minutes ago, N201MKTurbo said:

You want Lycoming Service Instruction 1290F. It is titled "Crankcase Thru-Stud Locations, Repair of Oil Leakage, Assembled and Unassembled Engines"

 

Fantastic information. Thanks so much.

[N201MKTurbo]

I found a PDF on Vans Air Force. I'm awaiting activation of my registration. I will post it here when I get it.

Lycoming SI 1290F.pdf

[PT20J]

1 hour ago, Shadrach said:

@RoundTwo

Unless all the shops that are local to you are really backed up, borrowing a case is not going to save you much time. It took me ~6 hours to remove my engine from the airframe and remove al accessories. I dropped the engine at my engine shop late morning, and they had the case halves created and shipped by 4:30 that afternoon. Shippin, Overhaul and Assembly will take more time.

All of the above being said, Lycoming SI 1290F (requires a subscription to view) was released for a reason. Without evidence that the leak is from a case crack, it would be prudent to pursue the least invasive repair.

 

Shouldn’t require a subscription. What they told us in the factory class is that Lycoming only puts the most frequently requested service literature on the website. But, if you contact them, they will send you any that aren’t available there.

[RoundTwo]

2 hours ago, Shadrach said:

@RoundTwo

Unless all the shops that are local to you are really backed up, borrowing a case is not going to save you much time. It took me ~6 hours to remove my engine from the airframe and remove al accessories. I dropped the engine at my engine shop late morning, and they had the case halves created and shipped by 4:30 that afternoon. Shippin, Overhaul and Assembly will take more time.

All of the above being said, Lycoming SI 1290F (requires a subscription to view) was released for a reason. Without evidence that the leak is from a case crack, it would be prudent to pursue the least invasive repair.

 

I’m definitely leaning towards an oversized through bolt as outlined above. For once things are looking like a simpler fix is the route to go.

[Shadrach]

12 minutes ago, PT20J said:

Shouldn’t require a subscription. What they told us in the factory class is that Lycoming only puts the most frequently requested service literature on the website. But, if you contact them, they will send you any that aren’t available there.

That’s an interesting policy. I would bet that the entirety of their AD, SB and SI library is well under 5GB. The cost of hosting the data online is trivial. 

[EricJ]

4 hours ago, RoundTwo said:

I’m definitely leaning towards an oversized through bolt as outlined above. For once things are looking like a simpler fix is the route to go.

Splitting the case requires replacing all of the main bearings, etc., which is an additional expense (and probably delay) that you can avoid by pursuing the through-bolt option.

[201Steve]

Divco will expedite your case work for only like $2-300 extra. I tried this with my overhaul with Zephyr, but he said don’t bother bc it’ll just sit on the shelf at his shop rather than at theirs. 
 

You could use Jewell to expedite it, they just skip that step! (unless the find a crack with dye penetrant) 

[RoundTwo]

7 hours ago, 201Steve said:

Divco will expedite your case work for only like $2-300 extra. I tried this with my overhaul with Zephyr, but he said don’t bother bc it’ll just sit on the shelf at his shop rather than at theirs. 

Yesterday I quickly learned that I wasn’t going to “engineer” my way out of long lead times if I was going to go down that path.

7 hours ago, 201Steve said:

You could use Jewell to expedite it, they just skip that step! (unless the find a crack with dye penetrant) 

That would be a negative Ghost Rider. 

[RoundTwo]

12 hours ago, Shadrach said:

That’s an interesting policy. I would bet that the entirety of their AD, SB and SI library is well under 5GB. The cost of hosting the data online is trivial. 

I’ll be adding the one @N201MKTurbo found to our Downloads section.

[RoundTwo]

16 hours ago, Shadrach said:

All of the above being said, Lycoming SI 1290F (requires a subscription to view) was released for a reason. Without evidence that the leak is from a case crack, it would be prudent to pursue the least invasive repair.

 

After reading 1290F, this is the route I’m taking. Thank you for your input.

[RoundTwo]

9 hours ago, EricJ said:

Splitting the case requires replacing all of the main bearings, etc., which is an additional expense (and probably delay) that you can avoid by pursuing the through-bolt option.

And with 1620 hours on the motor since 1988, going the IRAN route, at this point in its life, probably wouldn’t be the best long term decision. I figure I’ve got an overhaul coming in the not so distant future, so keeping the case halves together for now is the plan.

[Shadrach]

On 1/30/2024 at 7:16 AM, RoundTwo said:

And with 1620 hours on the motor since 1988, going the IRAN route, at this point in its life, probably wouldn’t be the best long term decision. I figure I’ve got an overhaul coming in the not so distant future, so keeping the case halves together for now is the plan.

That depends on whether you’re planning on keeping the plane or selling. Buyers use SMOH as a proxy for engine health and expected remaining time in service. It’s not a great proxy, but it’s one of many metrics we use.  
When we had our case overhauled in 2011 the engine was ~900SMOH and 10 years old.  I was prepared to do a major depending on what we found inside. What we found was an engine that was well above service limits across everything we inspected, though we did not take measurements. The main bearings were in good shape visually but replaced as the OHd case had been line bored. We are about 650 since IRAN and I have as much confidence in the engine as one can have in a piston recip.

IRAN for operational utility 

Overhaul for valuation.

[RoundTwo]

5 minutes ago, Shadrach said:

That depends on whether you’re planning on keeping the plane or selling. Buyers use SMOH as a proxy for engine health and expected remaining time in service. It’s not a great proxy, but it’s one of many metrics we use.  
When we had our case overhauled in 2011 the engine was ~900SMOH and 10 years old.  I was prepared to do a major depending on what we found inside. What we found was an engine that was well above service limits across everything we inspected, though we did not take measurements. The main bearings were in good shape visually but replaced as the OHd case had been line bored. We ave about 650 since IRAN and I have as much confidence in the engine as one can have in a piston recip.

IRAN for operational utility 

Overhaul for valuation.

I’ve had it for less than a year at this point, so keeping it is the plan. I wouldn’t be against an IRAN, but since it’s original to the plane from 1988 and only 1620 hours, there’s a good chance there could be some age related issues that would lead to a more costly IRAN than a newer engine. Since I’ll be pulling a jug to replace the thru-bolt, I’ll have a great opportunity to scope around the inside for cam and lifter condition.

It is a bit thirsty for oil and the oil does get pretty dirty after 10 hours, so it may be time to think about cylinders, even those were done not terribly long ago.