Microlighters

Hi All

Has anybody resleeved the cylinders on a 503 Rotax? I had an overhaul of my 503 where the cylinders were resleeved, new pistons and rings fitted. 8 hours later the rear piston "cold siezed". There were scuff marks on the inlet and exhaust side of the piston and the scuff marks were halfway down the piston skirt. The AP says it looks like a cold sieze. At the time it siezed I was climbing out of a large valley at about 5500 rpm. I had been flying for an hour and 15 minutes prior to this. Can anybody shed some light on this I have heard from one person that resleeved cylinders have a high incidence of siezure.
P.S. Landed in very rough terrain. Anybody have two spare rims they want to sell?

[quote="alan"]Hi All

8 hours later the rear piston "cold siezed". There were scuff marks on the inlet and exhaust side of the piston and the scuff marks were halfway down the piston skirt. The AP says it looks like a cold sieze. quote]

What do they meen with cold siezed I am very concerned about all the engine failures lately. Is it not the lead replacement petrol we are using now

Hi,

Willie wrote:

Is it not the lead replacement petrol we are using now

The way I understand it, you should be using unleaded fuel for the Rotax motors.

Regards,
Arnulf

Arnulf wrote:Hi,

The way I understand it, you should be using unleaded fuel for the Rotax motors.

Regards,
Arnulf

Is that not only for the 912

Hi Willie,

In the Operators Manual for the 2 as well as the 4 stroke motors it is not pertinently specified that unleaded fuel must be used. There is only a note pointing out the increase in deposits and wear due to the higher lead content when using AVGAS.
The fuel specification for the 503/582 motors are the same as for the 912 according to the Operators Manual.
The fuel recommended is given according the European standard. In Europe leaded fuel has been phased out many years ago.

To get reliable clarification on this issue, the best would be to contact the manufacturer of the motors.

Regards,
Arnulf

alan wrote:The AP says it looks like a cold sieze

More likely to be a seizure due to lack of lubrication. A cold seize will normally have scuff marks all the way up and down the side of the piston, on both sides of the piston.

I have heard from one person that resleeved cylinders have a high incidence of siezure.

Two reasons.... a)if you don't do a proper break-in as specified in your Operator's Manual and b) if the tolerances are wrong.

I'm not saying that you didn't have proper lubrication, but if the tolerance between piston and cylinder were incorrect, then it amounts to the same thing

Duck Rogers

Willie wrote:What do they meen with cold siezed I am very concerned about all the engine failures lately. Is it not the lead replacement petrol we are using now

Lead replacement fuel has nothing to do with a cold seizure

Duck Rogers

Hi Guys

Sorry about the delay but have been away and busy. I use unleaded petrol with Castrol Super Outboard which is what I have always used. The engine was run in as per Rotax schedule including a stopwatch and instructions followed to the letter/second. I think the problem was tolerances not being correct. The final saga of this development was that the AP has agreed to go 50/50 with replacing it with a new short block. This after legal action was instituted. Costs of repairing undercarriage to trike will have to be borne by me
Although not ideal I think this was better than dragging it all out with huge costs all around and I am just thankful nobody was hurt (except my piggy bank). If somebody can show me how I will attach a photo of where I had to land.

alan wrote:The final saga of this development was that the AP has agreed to go 50/50 with replacing it with a new short block. This after legal action was instituted

Duck Rogers

Hi All

Just a photo of the trike in the terrain as mentioned. It could have been a lot more interesting

Holy Crap

Glad to see you made it OK.

My experiences with a resleeved engine are not good ,
Normally resleeving on a stroker should be done by a reputable engineering shop - not the normal shop that works on watercooled engines, but one that has the tollerances of a high revving aircooled engine - The type of material used should be of the same type as used in the Rotax engines - we have aluminium , steel and another typ of steel contained / preesed to fit and machined - expansion and contraction plays a role , a longer run in period / oil could play a role as well as a hard run , mild workout could have an influence - New type of oils , metals take much longer to wear in , so often the engineers will give it a slightly bigger tollerance , my personal favourite is to rather source a good used 2nd hand sleeve, hone it , fit new circlips , gudgeon pin and bearing and away you go , I have a DVD on rebiulding the Rotax engines , - if ya want one shout , will send .
, Leprachaun

Hi Leprachaun

Thanks for the offer. I was a sent a copy by Alex Rudd which I found very useful. Our terrain here is difficult although there are places to fly that are safer to land in but those are not usually the places I like to fly over as I am involved in wildlife This is the reason I fly.

Leprachaun wrote: I have a DVD on rebiulding the Rotax engines , - if ya want one shout , will send .
, Leprachaun

Please post me a copy to 12 Drommedarisstreet Phalaborwa 1390. With your banking details and cost