Mike Busch Not a Fan of Top Overhauls?

[Mooney Fan]

Just read his Jan 2014 article. Glad I didn't read it prior to buying my plane in April 2018. He is no fan of them. I currently have 228 STOH on cylinders 1,3,4 and 181 hours on cylinder 2. About 140/hrs are mine. So that gives me some solace.

What is the real world take from the wrenches here at PoA? Have you had any cases where the cylinder separated from the case of through rods trough them. Those are some of Mike's concerns

 

[NordicDave]

Mike Bush isn't opposed to TOH's, and in fact he's discussed performing top overhauls on his plane. His point was just replace the cylinders that need overhaul and not the whole top at one time if not needed. File his comments under "unnecessary maintenance" and possible introduction of maintenance related issues that would not have otherwise occurred.

IIRC, he expressed concern about losing the case clamping pressure on the main crank bearings.

This was my understanding.

Here's the whole presentation on the topic. You can judge for yourself:

-David

 

[Mooney Fan]

Mike Bush isn't opposed to TOH's, and in fact he's discussed performing top overhauls on his plane. His point was just replace the cylinders that need overhaul and not the whole top at one time if not needed. File his comments under "unnecessary maintenance" and possible introduce maintenance related issues that would not have otherwise occurred.

This was my understanding.

-David

This is the article

Cylinder Work: Be Afraid

https://www.savvyaviation.com/wp-co...s_eaa/EAA_2014-06_cylinder-work-be-afraid.pdf

 

[GRG55]

I haven't read the article you referenced, so not sure what is being used as a definition for "top overhaul". He is a believer in replacing cylinders as required, but not with the engine on the airplane. He did that selectively on his turbo 310, and had some 3000 hours since overhaul on the engines last I heard.

 

[Mooney Fan]

I have read as well he replaced them on his 310 which made his 2014 article even more interesting. I was incorrect in that it was in 2019.

 

[GRG55]

I have read as well he replaced them on his 310 which made his 2014 article even more interesting. I was incorrect in that it was in 2019.

On most horizontally opposed airplane engines the bottom end, properly maintained, will outlast the cylinders. The bottom ends on low stress engines, like the 250 sea level hp Lycoming IO-540 variants in my Aztec, are near bulletproof if maintained diligently. I'll be selectively changing cylinders in the years ahead if I keep the plane. I do not expect to ever have to open the case halves.

Busch replaced cylinders one at a time, as necessary, on his 310. I recall reading an article by him years ago (maybe the same one) about managing the engine this way. As I recall he always had the engine removed from his plane and on an engine stand, so there was no interference or access issues to get at all the fasteners and torque them properly.

 

[Let'sgoflying!]

Does the 310 have limited access to the cylinders?

Taking an engine off to replace one cylinder makes an easy job a pretty big one and surely introduces the opportunity to have more maintenance-related failures.

 

[Tom-D]

I don't follow Mike's advice too closely, simply because no two used engines are the same.

In this day and age we have no way to know how many hours are on any cylinder unless we know when new were plug in service.
I just inspected a 0-300-D that had very low compression, after being stored nearly a year. I suggested the owner remove the cylinders and have the local cylinder shop bore and re-ring them,, oops... they are already .015" over.

Too bad, so sad, 6 new cylinders are needed.
Now you really must make a decision as to whether the lower end is worth it.
a quick look in the log shows the crank was cut .010 under last overhaul 1400+ hours ago in 1986.
The bigger the hole is, the bigger it needs to be.

 

[Tom-D]

I like my engine to run smooth, as will an engine with balanced BMEP of new cylinders.

 

[3393RP]

Does the 310 have limited access to the cylinders?

Taking an engine off to replace one cylinder makes an easy job a pretty big one and surely introduces the opportunity to have more maintenance-related failures.

Yep, I have to believe doing twelve engine removals reaches the point of diminishing returns on about the fifth jug.

 

[jesse]

Does the 310 have limited access to the cylinders?

Taking an engine off to replace one cylinder makes an easy job a pretty big one and surely introduces the opportunity to have more maintenance-related failures.

Agree. If you have good access to the cylinder (you often do) it’d be super counter productive to pull the engine. You add risk all over. The fuel system, electrical system, other components...

I learned at a young age that’s it’s unwise to disassemble perfectly functional gadgets. The five year old version of me decided to overhaul a perfectly functional windup alarm clock with sentimental value.

In my defense, I had success with a plug in digital alarm clock. This gave me the confidence to tackle the wind up. I did not expect the springs.

 

[Let'sgoflying!]

he five year old version of me decided to overhaul a perfectly functional windup alarm clock with sentimental value.

omg. Were we...brothers? Or neighbors? I did that exact thing. To many other devices as well. Still doing it but in a more controlled fashion!

 

[Kenny Phillips]

Yep, I have to believe doing twelve engine removals reaches the point of diminishing returns on about the fifth jug.

You haven't taken "catastrophic engine failure due to bearing displacement caused by under-torqued fasteners" into consideration. And that must be taken into consideration. I've built many racing engines, car and motorcycle; if there's a chance to use a micrometer and measure stretch instead of torque, we use that method. (It can also be done with a stud, if it's accessible and long enough, with a dial indicator.) Torquing fasteners is rather a clumsy way to get things tight, but it's the best we have that is easy and generally available.

 

[Tom-D]

You haven't taken "catastrophic engine failure due to bearing displacement caused by under-torqued fasteners" into consideration. And that must be taken into consideration. I've built many racing engines, car and motorcycle; if there's a chance to use a micrometer and measure stretch instead of torque, we use that method. (It can also be done with a stud, if it's accessible and long enough, with a dial indicator.) Torquing fasteners is rather a clumsy way to get things tight, but it's the best we have that is easy and generally available.

I've yet to see a Mike that will reach across a case thru bolt, or measure the stretch of a blind stud.

 

[mondtster]

You haven't taken "catastrophic engine failure due to bearing displacement caused by under-torqued fasteners" into consideration. And that must be taken into consideration. I've built many racing engines, car and motorcycle; if there's a chance to use a micrometer and measure stretch instead of torque, we use that method. (It can also be done with a stud, if it's accessible and long enough, with a dial indicator.) Torquing fasteners is rather a clumsy way to get things tight, but it's the best we have that is easy and generally available.

Yet measuring stretch isn’t common practice at the OEM level, and they successfully assemble how many engines that go for thousands of miles/hours? I think I can say with confidence that the OEMs have more success with engines living using simple torques or a torque turn sequence than racers do, despite obsessing about measuring stretch.

But I agree that there should be great concern about making sure all fasteners are tightened/torqued after a cylinder change. That means taking things apart far enough to allow torquing both sides of any affected through bolt, which is a procedure that some mechanics seem to overlook. I’ve seen the results of not doing it first hand, when an affected cylinder decided to leave the party on a 421 less than two hours after a cylinder change.

 

[Stewartb]

The engineers have determined what torque provides the correct stretch. Rod bolts come to mind. Don’t overthink it.

 

[Checkout_my_Six]

here's my top OH....engine removed to gain access for proper cylinder torquing.

 

[Checkout_my_Six]

I've yet to see a Mike that will reach across a case thru bolt, or measure the stretch of a blind stud.

or a mic for that matter.....

 

[Checkout_my_Six]

Does the 310 have limited access to the cylinders?

Taking an engine off to replace one cylinder makes an easy job a pretty big one and surely introduces the opportunity to have more maintenance-related failures.

the Bonanza is horrible for cylinder access....It cost a few extra days work for peace of mind...knowing everything was done right.

 

[bnt83]

Clearly most of you should never fly in a helicopter, after all it has many more critical fasteners, bearings, and are often disassembled on a schedule rather than on-condition.

I've learned a few things from my rotory mechanic brother, twice Bell factory training, that just seems stupid NOT to apply to piston engines. Such as, why wouldn't you walk away for several hours then retorque cylinder hold down nuts one last final round?

There are torque inspections on those things that requires re-inspecting in like 5 hours if the fastener moved at the scheduled torque inspection. All those hours the ship can be operated on revenue flights.

 

[Tom-D]

Such as, why wouldn't you walk away for several hours then retorque cylinder hold down nuts one last final round?

because you must disassemble a lot of the engine to put a wrench on the cylinder hold down studs.

 

[Clip4]

When are pilots going to figure out Mike is full of crap.

 

[Cap'n Jack]

When are pilots going to figure out Mike is full of crap.

How so? I read that a lot, exclusively on this board, without any reasons given.

 

[Checkout_my_Six]

When are pilots going to figure out Mike is full of crap.

But he empties regularly...

There’s a lot of good... I will say he didn’t invent his schtick... just gathered and packaged the slide show. But it’s all good. IMHO

 

[Kenny Phillips]

The engineers have determined what torque provides the correct stretch. Rod bolts come to mind. Don’t overthink it.

The engineers have determined what torque provides the correct stretch under ideal conditions.

 

[Checkout_my_Six]

The engineers have determined what torque provides the correct stretch under ideal conditions.

and if the procedures are not followed....exactly....the anticipated bolt stretch doesn't happen.

 

[timwinters]

How so? I read that a lot, exclusively on this board, without any reasons given.

Do a search foe "Mike Busch" here and you'll see the reasons. Here's but a couple...

1. Over at CPA. He asserted that you don't need to worry about moisture in your oil in the winter...because the air is too dry. Others had to point out to him that moisture in the oil is a byproduct of combustion, not the air.

2. But my favorite was when Mike asserted (repeatedly) that you should never stop at the SS pump upon your return home to fill up. You should instead taxi to the hangar and call the fuel truck. You'll save money by calling the fuel truck, even though the gas is higher, because every start up imposes excessive wear and tear on an engine, even one that occurs within 15 minutes of shut down when everything is still warm. He finally conceded that that he had a case of cranial rectitus on that one...don't recall if he ever did on the first example.

If he's an "aviation expert" then we're in deep sh*t.

He should rebrand himself as "savvy marketer."

 

[Cap'n Jack]

Do a search foe "Mike Busch" here and you'll see the reasons. Here's but a couple...

1. Over at CPA. He asserted that you don't need to worry about moisture in your oil in the winter...because the air is too dry. Others had to point out to him that moisture in the oil is a byproduct of combustion, not the air.

2. But my favorite was when Mike asserted (repeatedly) that you should never stop at the SS pump upon your return home to fill up. You should instead taxi to the hangar and call the fuel truck. You'll save money by calling the fuel truck, even though the gas is higher, because every start up imposes excessive wear and tear on an engine, even one that occurs within 15 minutes of shut down when everything is still warm. He finally conceded that that he had a case of cranial rectitus on that one...don't recall if he ever did on the first example.

If he's an "aviation expert" then we're in deep sh*t.

He should rebrand himself as "savvy marketer."

If he conceded he was incorrect on one of them, he's better than most internet "experts", including those that post in this board.

 

[Timbeck2]

Well, he certainly knows more than I do and I doubt anyone can get it right 100% of the time. I'm going to buy a couple of his books.

 

[kyleb]

When are pilots going to figure out Mike is full of crap.

Maybe in some areas, but I agree with his philosophy on cylinders. A TOH implies pulling all of the cylinders and rebuilding or replacing them at one time. Mike believes in replacing or repairing cylinders on condition, and I agree with that. Each cylinder is a unique assembly and if one has a problem, that isn't an indictment against the others.

 

[timwinters]

If he conceded he was incorrect on one of them, he's better than most internet "experts", including those that post in this board.

Yeah, but really? A man who purports himself as an expert doesn't (or didn't) know that moisture in the oil is a byproduct of combustion? Really?

I'd surmise that even 90% of our right brained pilots understand this. (like Mike surmises so many things.)

 

[1RTK1]

He was probably referring to ambient moisture

 

[Tom-D]

Maybe in some areas, but I agree with his philosophy on cylinders. A TOH implies pulling all of the cylinders and rebuilding or replacing them at one time. Mike believes in replacing or repairing cylinders on condition, and I agree with that. Each cylinder is a unique assembly and if one has a problem, that isn't an indictment against the others.

So, You are down a week this month, then again next month for another cylinder, then again the next month, and so on.
It doesn't require that much more time to change them all.
But maybe you can only afford one cylinder a month (?) been there too.

 

[bluerooster]

Based upon the article that I read, it would be best to replace opposing cylinders at the same time. Bein's how both ends of the through bolts need to be properly tightened anyway.

 

[Mooney Fan]

In regards to engine starts leaving SS. He sounds more like an engineer than mechanic. My old man is and engineer and back in the 70's I was starting my Kawasaki just for fun to hear it run. He says "You know, that engine is only going to start 'X' number of times, and you just reduced it by 1"

 

[Tom-D]

Based upon the article that I read, it would be best to replace opposing cylinders at the same time. Bein's how both ends of the through bolts need to be properly tightened anyway.

Unless there is a really good reason not to, do them all and be done.

 

[Checkout_my_Six]

It's not always needed....that's why. But, in most cases dropping the exhaust and intake is a good reason to keep going and take the side of cylinders off. Sometimes both sides of the exhaust need to come off...so, I'd agree with the complete top job.

But, maintenance induced failures are a real thing....and something to think about.

 

[Cap'n Jack]

Yeah, but really? A man who purports himself as an expert doesn't (or didn't) know that moisture in the oil is a byproduct of combustion? Really?

I'd surmise that even 90% of our right brained pilots understand this.

Agree, but as things are peaceful now, I'll not mention some here who might have a worse batting average. I'll drop it and thank you for explaining some of the hate.

 

[kyleb]

So, You are down a week this month, then again next month for another cylinder, then again the next month, and so on.
It doesn't require that much more time to change them all.
But maybe you can only afford one cylinder a month (?) been there too.

Thanks, Tom. I was hoping you'd jump in with a helpful comment. The internet just wouldn't be the same without people like you.

 

[NordicDave]

Comparing Self-Serve to full service... Depends on the price differential of the fuel service. My last field the priced for both were the same, and current field it's 20 cents per gallon more. My current hangar is 5-6 minutes taxi away to the SS pump and about 10 mins to the dominate runway. Avoiding another start and cost of fuel to taxi, the extra $12 average per fill is worth it.

His engines did make it to 3220-ish hours since overhaul without replacing cylinders.

-David