I remember going back a number of years now, we had an mg roadster come in to the shop with the customer complaining about poor performance... high mileage on the engine... tore the engine down for service, and all 4 exhaust valves were so badly coked up, the carbon deposits around the exhaust valve stems almost filled the exhaust port... looked like a morel mushroom wrapped around valve stems.... the carbon build up was hard as a rock... surprised the engine ran as well as it did..

I can feel them, but barely. Enough to lose a bit of piston ring seal.
What is less favourable, the liner moved out a bit when I turned the engine over, and I twisted it a bit when pushing it back in place. So the ring needs to re-seat.

Do you think a ring with that much run time will reseat?

Re-seating is probably the wrong word, but rings that have been seated in a liner, then somehow got displaced, are known to "search" for their old position relative to the liner.
I have seen it happen multiple times.
It is not the same as the seating of a new ring, it is more like finding back its old position.

Yes, sometimes they will find their old home quickly but sometimes they won't.

I tore apart a used Saito 82 for clean up, marked the position of the ring while carefully removing the cylinder, kept track of the ring's right side up position, reassembled and after 2 gallons of methanol the ring was still "searching" for its old home. I was modding the compression ratio on that engine a little at a time and every time I pulled the cylinder up to take a peak the ring was in a different position. The compression feel would change from one run to another, sometimes feeling decently firm and sometimes feeling fluffy. The ring was previously broken in but very low time, still had pronounced marks on its edge from Saito's grinding process, and the ring groove was spotless clean so the ring could spin around freely, which it did for those 2 gallons and 3 more. It wouldn't keep a consistent idle tune. Then one day while flying the engine went unusally rich in flight. When I checked it the compression was rock hard and hasn't changed since, but 5 gallons to re-break in? The only thing I can ascertain is that the ring was a wanderer, went for a walk about and found a dozen "new homes" before finally settling on one.:D

What sort of remedies are there for this?

Had a look Dave and some stuff quickly went over my head - Is it as simple as flashing an Arduino and Using the configurator? All I need is two temp readings and Maybe RPM ... Can it be configured for that only?

I know exactly what you mean, and all I can do is wait. It never is going to be perfect again, but then again, this situation seems to not affect performance too much (almost "not at all"), so I am not too worried.

None except new liner and ring, or if the liner is without marks, just a new ring.

Unfortunately, those are getting scarce.

I've had success "finger honing" glazed cylinders with 600 grit emery cloth. Creating a cross hatch pattern isn't really that difficult by hand. If the scuffs on your cylinder wall aren't worn in too far they will show scratches after just a few passes with the emery cloth. If the scuffs stay shiny then it's time for a new cylinder liner. I install new rings after honing, no problems so far.

The Saito 56 I honed and ringed 6 years ago must have over 100 flights on it and still runs strong.

It's pretty close. You need to set the steinhart constants for the temp sensors as well as a couple more items in the config file. I make these with 2 temp and rpm all the time. Wiring will require a couple 4.7k resistors and the thermistors for the temp sensors.

I can mail you one if you wasn't

Thanks to all for the info on the temp sensing - I do have parts required for the OpenX setup here Dave and will give it a try. Will let you know if I run into issues - Do you have a spec for the thermistors you use - Have some here but I don't know if they will spec out right.

I do have a Graupner General Air Module here which does two temp inputs but its a bit of a big unit just to do what's needed.

Very possible that I will do that in the future, but not now... Rings probably are not so much a problem, but liners are hard to find. I can have one made, but still...

The datasheet for the specific thermistors you have will have a table providing several resistance and temperature pairs. Those pairs can be put into one of the steinhart calculators available online and the resulting steinhart coefficients (A, B, and C) get entered into the config file. Post the thermistor part number and I can send a config file for you to build the firmware. I build these using a nano.

... i use this calculator: https://www.thinksrs.com/downloads/p...alculator.html

Well, MikeGoesFlying has 1 piston sleeve in stock for the Magnum FT160 (same as the ASP)... or possibly the OS sleeves will fit when the time comes... I know some OS parts are interchangeable... do the matching set for each side with the OS piston, ring & sleeve... Or have sleeves made, would not be that difficult, its just a flanged straight cut sleeve.

A paddle stone master cylinder hone with the spring tension set low ( not one of those ball flex hones ) will break the glaze without increasing the bore dia, just use a slower speed. and check the process often.

I just tried to order, but MGF apparently does not ship to Europe.

Bummer.

ship it to me and i'll drop it in the mail to you.

Would that work? Because MGF standard requires PayPal, and I know Paypal basically automatically generates a shipping adress. No idea if that overrules or not.
I am willing to pay you beforehand, but feel more confident if you would handle the purchase part, to make sure it ends up at your place to begin with.

I recently sent a package to the US to BravoGolf (RCG user) and after about 2 months whizzing around in the US (Barrie was able to partially track the packages movements) it sudedenly ended up in my mailbox again, and I have no idea why...

they usually let you specify a billing address (which will match your paypal address for that specific card) and a different shipping address.

anyone else who wants to send me stuff is also welome to do so.

Robert (old buddy from RCGroups) allready contacted me and offered to ship it to me. I can't ask two people at the same time :D :D :D

you can but you would need to buy 2 parts too. for everybody else, you can still feel free to send me stuff.

Rings from Bowman/RJM here in the states are my choice. OS, Magnum and Saito rings are not always round enough to break in quickly. When I install a Bowman ring the compression is rock solid after running one tank of fuel, every time. Often the compression is rock solid after reassembly alone, something that has NEVER happened using other brands.

Robert has ordered the Liner for me, and it was the last one.
A ring I can get from JustEngines who still has a few.

Unfortunately that meet has been postponed to Sunday 25th, but hey, maybe I will have the parts (liner and ring) in the meantime, and if so, I will also check the other side and clean if necessary.

That will be very interesting to see.