what causes scoring , on a piston , in the area of the exaust port opening?

Could be a burr on the sleeve or maybe a little dirt or something could have found it's way in.

Where exactly?

Dirt ,use an air filter.

If it's at the rear of the exhaust port only it could be due to overheating from a lean run without castor oil in the fuel.

Normally, this would be heat, too large a prop, too short a tuned pipe or too little oil.

Or it could be a disintegrated glow plug coil. Messed up one of my Irvine .53's! [:@]

yea. it is in the rear exaust port, the engine is a BGX 3500, the compression is good and the ring is not damaged, the top of the cylinder head looks good also, probably dirt got in it.

Has anyone siezed up an ABC motor to the point the piston locks? Can a piston and cylinder like this be revived?

Wow! I didn't think it was possible for a modern ABC to sieze because of the metallurgy. The hotter it gets the more the sleeve expands. I had an OS61fx lose a prop in flight and wailed like a banshee before I could shut it down. When I landed it was impossibe to touch the cylinder head. That engine is still running fine today! Only exception would be if it ingested some debris and jammed. Then a new liner and piston would be in order. Also check the crank shaft for cracks around the intake port.

Good Luck,

Phil

Number one reason for scoring of a piston : OS engines ! They use cheap nickel lining that peels and messes up everything very quickly [:@]

If you dont want scored pistons, dont buy OS, buy an engine with the more expensive chrome plating.

JettPilot

more expensive than O.S. ? IS there such an animal?

Why is it that all fo you ruin O.S. cylinders? I have run them for nine years now
and never scored one in normal usage. I use .46 fxes and one .50 ax.

well i'll tell ya T , I BOUGHT it used and they just tried to get too much RPM out of it on 15%
its only supposed to get 8 grand max , luckily there is only slight damage. its VERY important
that people read the instructions , and dont try to get more rpms than specified, and run them
too lean.

I would like to see your OS engine-s thats has peeled a nickel liner or chrome ,gives us all the particuars ,plug type ,fuel used ,prop size and RPM and of course engine size .Also would like to know what the manufacture did to resolve the issue with said engine or engines .The only reason I have seen that makes a cyl or piston score in the exhaust port is due to over heating or lack of oil .Dirt is a possible but as a rule it wont pick just the exhaust port its all around the piston .

cyberwolf,

I think a few people on this site repeat what they have read and don't have too much first hand experience with OS and or the peeling condition.

I have been fortunate in that I have never had a problem with OS engines and only had fluke problems with Saitos. No problem with Enya engines except where to get them now. I think Enya production is on the way out.

SkyPilot

I do not believe Enya production is not on the way out. The British distributor is now stocking an all new .40 size 2 stroke (ENYA .40 XZ). I hope more sizes follow. Links:

http://www.swdistribution.co.uk/

http://www.swdistribution.co.uk/inde...C&area=Engines

The full range of Enya engines is showcased at the link below ... plenty to choose from:

http://www.swdistribution.co.uk/inde...e=Enya+Engines

I think the problem with availability in the US is the distributor, not the manufacturer.

fiery

fiery,

There was a Enya distributor in Australia, where did they go?

Several of the engines in stock at SWD have not been produced in 15 years or more. At those prices they will have that old stock a very long time.

I am surprised to see that 40 engine. I hope Enya will continue but they will have a difficult time competing with other more popular brands.

I think the owner of Enya has passed away and his sons had taken over, but I could be wrong.

At one time Enya was owned by several brothers. Each handled a different part of the business. Are you saying the last of these brothers passed away?

There has been a problem with the USA importer for a long time. They only wanted to import the best selling engines. I thought that problem had been solved. Perhaps not. Until looking up Enya on the internet many of us did not know that some of the sizes existed.

On the OS, AFAIK, the problem of the thin plating on the cylinder was only for a small time-slot. They then came out with their current plating system. I believe the problem occurred with lean runs and insufficient lubrication in the fuel. Most never knew the problem existed. Perhaps it was part of the plating development. If you think you have this problem you can remove the head and look into the cylinder with the piston down. If you see pure brass in a spot, voila!

George

Hi SkyPilot

The main Aussie distributor for ENYA is:

http://www.modelflight.com.au/powered_enya_engines.htm

The prices are still high, compared to what you may be used to in the 'States.

ModelFlight are a major distributor of R/C items in Australia. They sell direct to buyers in the US.
I have had good dealings with them.

The larger ENYA engines (1.55 Four stroke, 1.80 Two Stroke) are also available in Australia from a
hobby shop specialising in pattern, the name of which presently escapes me.

Cheers

fiery

Every OS engine I have had has also peeled the nickel liner. Its well known that nickel is cheap and peels easily, and its even better known that OS has had these problems for a long time. This "give me the particulars" is just a way for you to rationalize your denail. Its happening, a LOT. All you have to do is read this forum or do a search on the problems, its well documentd with LOTS of people.

But then again, you sound like one of those people in denial that done want to see what is right in front of you.

Thanks for the website.

The only engines that have high prices there are the four strokes, the rest seem in line.

dominiqueFrance,

How many OS engines have you had?

Not one member at my club of 140 members has mentioned a OS liner peeling and many fly OS.

If I had ruined every O.S. engine that I owned, I don't think I would make that information public.

Hee Hee