trying to find where Rotax says to replace crankshaft and when

[GyroRon]

I thought it was mandatory to replace crankshaft on Rotax engines at 300 hours when overhaul is done? Anyone got any info on this?

 

[gyromike]

Ron,

You can download a service manual here:
https://www.rotax-aircraft-engines.com/pdf/dokus/d00288.pdf

It recommends a general overhaul at 300 hours.
I guess a new crankshaft is part of the general overhaul.

 

[GyroRon]

Well that is the question..... I was always under the assumption that the crank was to be replaced at 300 hours, but have been in a arguement with a rotax repair station that says it doesn't have to be replaced if it specs out. I want to know if I am right or blowing smoke as he says.....

 

[jdalexa]

Ron,

The recommended TBO on the crank - per Rotax - is 300 hours. The key word is recommended. These are non-certified engines. You can do what you wish. There is rumor they are about to bump that to 450.

The 150 hour inspection (the one everyone calls the decarbon) should actually be a complete teardown with diagnosis of the condition of crank, pistons, cylinders, rings, clearances and so forth. It takes about 8 hours work. Armed with that knowledge, when it hits 300 hours, if the crank is still within wear limits, you can make the decision as to whether or not to replace it. If you do not replace then, make sure that you do a full teardown at 450. By then it will quite likely be ready for replacement.

I'm doing a 150 hour on a 503 now. It was built in late 1997. All is quite well with the engine, but the seals are crap now.

The pix show some of the reason for cracking it open regularly. The first is a 582 crankshaft. Note the center helical cut gear. The second picture is the rotary valve shaft. That is a brass gear that meshes with the steel one on the crank. If this goes, your water pump stops as well as the rotary valve allowing fuel/air mix to the engine. Not to mention all the bits. There is also a rubber oil seal on the left side between the gear and big bearing.

That brass gear is about $85. The RV shaft comes all apart and is fully and easily servicable. Catch bad things early and save in the long run. The shaft by itself runs about $160.

By the way, this steel and brass gear mesh is why you should change your RV lube oil (small oil container on the carb side) every year. Whatever 2-stroke oil you use is what you put here.

These are also press fit cranks rather than forged ones like in a Continental or Lycoming. Checking runout on a relatively frequent basis becomes <good>.

You rely on the 582 on your gyro no less than the O-320 on your RV. Give it the same treatment.

The cost of parts for a 582 blue head for the 150 hour inspection are $260. Not a bad deal. Where you get hit is labor or the cost of tools. (I charge $520 labor for a teardown) The Rotax tools are very costy. They are around $700 for the 582-99 specific tools needed to do the job right.

 

[GyroRon]

John, the repair station is a place in Oregon that advertises on Barnstormers for new and used engines. His most recent ad is for a 582 with zero hours since major overhaul and he wants 4 grand for it. Just cause I was bored I sent him a email.... here is it

When you say major overhaul, do you mean you followed Rotax specs and
replaced the crankshaft with a new crank? What about Pistons and so on???

Hi


So are you ready to buy an engine or are you just blowing smoke?


Let's not start by insulting each other shall we...


Yes it meets Rotax new and or serviceable specs throughout, just as the ad states.


We do not change cranks at 150 hrs.


We always go completely thru each engine we re-sell.


Thanks


Bill Larson
Chief Designer
Federally Authorized Airframe and Power plant Technician
Web site: Oregon Aircraft Design LLC
Phone: 503-267-1486
Fax 503-647-0416

I am not blowing smoke, and your responce to my email tells me alot about your operation, thank you.


According to Rotax specs the crankshaft must be replaced at overhaul. Surely a Rotax repairstation would know this. When you are advertising engines as your advertising them then someone who follows the manufactors guidelines would tend to expect a new crank assembly in the engine, not one that was checked for runout and so on. I have 2 friends building gyroplanes in need of 582 engines and was checking into your engine for them.






Ron Awad

You know nothing about our operations, nor, obviously what Rotax mandates.


Good luck with your smoke blowing.



Bill Larson
Chief Designer
Federally Authorized Airframe and Power plant Technician
Web site: Oregon Aircraft Design LLC
Phone: 503-267-1486
Fax 503-647-0416

So as you can see he certainly doesn't think they need new cranks to be considered a overhauled engine.

My whole reason for writing him was based on how many times I see engines advertised as just overhauled or rebuilt when in fact it was more of a disassemble and take a look at everything, put on new rings and new seals and gaskets and reassemble.... to me that is not a overhaul. A lot of unsuspecting people get duked out of their money buying crap that isn't what it was passed off as, and I had a feeling this guy was doing just that. We also have two local people here gettign ready to build Dominators and both need engines so I thought, if this guy did do the engines right, this one might not be a bad deal....

 

[CLS447]

So, that 582 only had 150 hours on it when it was overhauled ?

Do you think it needed a new crank? How much is a brand new 582?

 

[scottessex]

If you look in the rotax book, there is a maintenance schedule, and the crank is recomended to be changed at 300 hours.
At $1200+ for a crank exchange, most people won't do that to an engine they are re selling. But I agree if it does not have a new crank it should not be called an overhaul.
I have been rebuilding, repairing, and overhauling aircraft hydraulic components for about 14 years. All of it is certified for 767 757 MD80-88-90
737 etc. The manuals all have wear limits for that reason, I use micrometers every day. if something is still within service limits, it is ok to use again.
So, If a customer, say Fed Ex sends us a pump, and they want it repaired, we repair as nessesary, measure all parts etc. Now if a customer wants, an overhaul, there are certain items that MUST be changed at overhaul regardless of weather it checks good or not.

If someone sells you a overhauled (new crank) rotax, they should be willing to give you a warranty of some sort, if not, it is a rebuilt engine that has had the run out checked, pistons and cylinders miked etc.

Nothing wrong with an engine that has been put together with servicable parts, but it is not "overhauled" it has been "rebuilt"

I just did a 150 hour on the Hirth, I cleaned and measured everything, everything was within manufacturers spec's except the fan bearings, I got new ones. so I changed gaskets and seals and will push on for another 150 hours.

Hope this helps.

 

[Jazzenjohn]

I could be wrong, but my understanding is that an Overhauled engine is taken apart, inspected, anything out of spec is replaced, reassembled with new gaskets and seals. Things that are recommended to be replaced are not automatically replaced. An engine that is Zero Timed should have a new crank though.

I don't know if there is a standard definition of these things somewhere.

 

[jdalexa]

Rotax doesn't specify a crank replacement at 150 hours, but at least in my thinking - zero time since major overhaul would mean a new crank. Not just a crank/pistons/cylinders that meet wear limits.

Pistons and cylinders are replaced on condition. It is not specified that they be replaced at the 300 hour major.

I'm baffled by this guys attitude. Part of what I see as my mission as a repair station is to educate my clients about these engines. If that means they watch my work - fine. I've got no "trade secrets" and I understand there are a lot of misconceptions about these engines.

All work I do on engines is fully documented. Just because these engines aren't certified doesn't mean we shouldn't treat them as if they were. Doesn't matter that they cost a lot less. You're still flying with them.

 

[jdalexa]

Right with you there Scott. A zero since major indicates a new crank. An inspected used engine would indicate that runout, axial play on the crank, ring end gap, cylinder conicity, piston to wall clearance, and so on had been checked and found to be within wear limits.

If I was buying a used engine that had been inspected, I would want documentation - which is why I provide it.

If you look in the rotax book, there is a maintenance schedule, and the crank is recomended to be changed at 300 hours.
At $1200+ for a crank exchange, most people won't do that to an engine they are re selling. But I agree if it does not have a new crank it should not be called an overhaul.
I have been rebuilding, repairing, and overhauling aircraft hydraulic components for about 14 years. All of it is certified for 767 757 MD80-88-90
737 etc. The manuals all have wear limits for that reason, I use micrometers every day. if something is still within service limits, it is ok to use again.
So, If a customer, say Fed Ex sends us a pump, and they want it repaired, we repair as nessesary, measure all parts etc. Now if a customer wants, an overhaul, there are certain items that MUST be changed at overhaul regardless of weather it checks good or not.

If someone sells you a overhauled (new crank) rotax, they should be willing to give you a warranty of some sort, if not, it is a rebuilt engine that has had the run out checked, pistons and cylinders miked etc.

Nothing wrong with an engine that has been put together with servicable parts, but it is not "overhauled" it has been "rebuilt"

I just did a 150 hour on the Hirth, I cleaned and measured everything, everything was within manufacturers spec's except the fan bearings, I got new ones. so I changed gaskets and seals and will push on for another 150 hours.

Hope this helps.