Rings for Rotax 912 (non Rotax)

[RFguy]

What factory alternative options are there for rings for 912 engines?

 

Rotax have ONE set of rings for ONE cylinder at $275 !!!!  all I can say to the factory  is F.O. I am not going to pay that (they want you to buy new engines) 

 

I have a 912 with 1900 hours that might want a set of rings.

-glen.

 

 

 

[facthunter]

It's unlikely that Rotax MAKE the original ones. Who makes the pistons probably supplies the rings with them  Nev

[onetrack]

I'm not sure that you'll find satisfactory quality rings a lot cheaper than the Rotax price. The U.S. site below advertises "high quality" aftermarket rings for Rotax, but they're still AU$180, and you'll need to add freight to that figure.

 

The confusing part is they state "complete set" (of rings) - but don't say whether it's a complete full engine set or a complete set of rings for one piston. I did note one site selling individual rings (genuine) for the Rotax 912, which I find rather strange. We used to have a local bloke supplying individual rings for pistons at one time (he's long gone), but he specialised in doing that for people who broke single rings when installing new sets.

 

https://sideslipaviation.com/products/piston-ring-set-for-rotax-912-complete-set

 

Edited September 3, 2023 by onetrack

[facthunter]

Re-ringing is not very common these days where good air filters are the norm. Often the top ring groove will have some wear if you need rings. For motor vehicles it was Usually the complete set. Japanese motor bikes sell one bearing half for the big ends sometimes.. With the two stroke Rotax's I mostly put new pistons in at the same time. Nev

[onetrack]

If rings are worn, the piston ring grooves will be worn too. Manufacturers generally set a specification for maximum wear level on all components. In general, any level of wear that exceeds 50% of the maximum wear specification measurement means that the component should be scrapped and a new component installed. If you want new engine performance, you fit new pistons, new rings and new cylinders.

[facthunter]

The Nikasil cylinders on the Rotax survive well and don't corrode. Some Cont and Lyc cylinders are NITRIDED.. Nev

[Thruster88]

5 hours ago, RFguy said:

What factory alternative options are there for rings for 912 engines?

 

Rotax have ONE set of rings for ONE cylinder at $275 !!!!  all I can say to the factory  is F.O. I am not going to pay that (they want you to buy new engines) 

 

I have a 912 with 1900 hours that might want a set of rings.

-glen.

 

 

 

Do you know the results of the last leak down? How much beyond tbo are you going? My thoughts, if it isn't broke don't fix it.

[facthunter]

You'll feel it when you pull it through when checking the oil level.  Nev

[RFguy]

Sideslip aviation was a good start. we'll see what else turns up, I will advise if I find further info ,

 

thanks for input     - glen.

[facthunter]

 Glen IF you are going to pull it down I wouldn't order anything until you've assessed it's condition. There's a good argument for replacing high time pistons anyhow it the motor's down in any performance or critical motor.  Nev

[RFguy]

that's right, it's an IF.

 

[turboplanner]

On 03/09/2023 at 9:56 AM, RFguy said:

What factory alternative options are there for rings for 912 engines?

 

Rotax have ONE set of rings for ONE cylinder at $275 !!!!  all I can say to the factory  is F.O. I am not going to pay that (they want you to buy new engines) 

 

I have a 912 with 1900 hours that might want a set of rings.

-glen.

 

 

 

It does come as a shock but when you realise that these engines rely on exotic processes and specifications that produce power beyond the dreams of the old 1960 equipment where a set of rings was petty cash it makes sense. Don’t forget this engine family comes from JetSki and Snowmobile applications where bhp over 300 is not unusual. In this market if you want to operate economically you always sell the product before the unscheduled maintenance is due to start.

[BrendAn]

On 03/09/2023 at 4:43 PM, facthunter said:

 Glen IF you are going to pull it down I wouldn't order anything until you've assessed it's condition. There's a good argument for replacing high time pistons anyhow it the motor's down in any performance or critical motor.  Nev

1900 is not bad for a 912.   i know of a 100 hp 912 that has 3600 hrs and is still passing leakdown tests. doesn't burn oil either

[facthunter]

Pistons fatigue. It's not just about wear. and they are in an aeroplane. Buying the piston(s) compete with the matching ring set is cheaper than with those parts separate.   Often done with 2 strokes for the same reason.  Nev

[facthunter]

BTW I've done more research on the Later 9xx engines . As well as a stronger case the crankshaft has been made stronger. It's all on a rotax website about the company.  Nev

[facthunter]

IF the crank is out of true there's no fix permitted even by the factory. You get a new one. It's not made to be pulled apart and reassembled as you can't keep the tolerances needed.   Nev