I finally got around to doing what i had in the back of my mind for a few months.
I had this worn out ASP 40 engine which was otherwise okay except for lack of compression - wasn't generating serious power.
So I changed the bearings- easy to do- costed Rs. 120/- for the pair.
Didn't help much.
Last Saturday I hunted around and found a chrome/ nickel plating guy who chrome plated the cylinder for me.
The mistake we made was that the outside as well as the inside was plated - so we had to grind off the outside layer- says the next time he will do only the inside.
He had polished the inside lining. and i had left the piston with him, so he worked it to a tight fit.
Picked up the assembly today.
Got back home, fitted out the engine and ran it on prime- fired up.
So i mounted it on a high-winger and ran it at 1/3 throttle -rich for 4-5 min.
Power and RPM seemed fine- should be enough to fly the model which is a heavy japanica Kolkata high-winger.
I will need to wait till Sunday to run a tank and a half of 25% castor oil fuel through it- sort of re- break in.
Then need to fly the bird.
The plating seemed okay, because it really had to be ground off on the outside.
Will post the RPM data and flight feed back coming Sunday.
Costed me 3 hours of time and Rs. 150 +20(tip to the technician who was thrilled to see the little engine).
Much cheaper than a new cylinder piston set- costs close to Rs. 2400/- for an AX 46.
The real proof will come after the first 25 flights.
regards,
Avijit

Doc,
The ABC need not run with 25% castor that was meant for the lapped iron pistons of yore. You use your normal everyday fuel and just need to run the ABC (in your case true chrome) slightly rich, peak back off and repeat again as it is the heat cycle which does the breaking in for the ABC/ABN/ABL (as different manufacturers call them).
If your efforts bear fruit, you will be a much sought after Man!
Lets see the engine in action coming Sunday, would wait impatiently

Really nice effort to success,
              Even a friend of mine did the same with an asp 28 he had, but the plating peeled off as soon as piston was inserted.

20% castor,not more than 10% Nitro, Never Syth alone is the key for ABC...am i right ?

Nai Augustine sir, they prescribe no nitro for ASP..
only 20% castor oil and 80% methanol

here is the extract of my manual, for break in cycle of 30 min each with throttle fully open at rich (Sloppy rich) setting and working our towards lean, i use 5-7% nitro. all my ASPs is one flick start. i got the manual in pdf format, if you need it let me know,

I am a hard core believer of Castor oil for model engines.
Without doubt it is the best lubricant available- a lubricant is meant to lubricate- there are excellent cleaning solutions available to polish up your model after the days flight.
Cox engines which have very tight tolerance limits recommend only castor. so do diesels.
Castor oil is easily available and fairly cheap (even though the price has gone up from 95/kg to 140/kg over the last 2 months due to some market shortage) in India. It needs to be specially ordered in from SIG etc in the west and is costlier than synthetic, hence the synthetics are popular there.
Might as well use the good things which are easily available here- better for the engine as well.
regards,
Avijit

You are absolutely right Capt. regular fuel should do.
I always use 22-25% castor for break ins because the new engine needs more lube not more methanol or nitro when it is broken in. I don't run it very rich, 3 clicks rich of peak RPM at 1/4 to 1/3 throttle for the initial 2-3  five minute cycles.
I like to see the engine spewing out a lot of clear unburnt castor oil from the exhaust when i am ground running the engine.

what about the sweet smell of it, ? i think i m addicted to it

I have a student (aero) using pure synthetic with ABC engines with ONLY 15% oil content on 2C engines without ANY problems whatsoever. You just need to make sure you are not excessively leaning out the engine.

Castor is undoubtedly a very good lubricant. The advantage is its low cost and its "forgiving" nature w.r.t lean runs. However, particularly with 4C engines, it can cause rough running as well as carbon build up on the valve seats over a period of time. With Klotz, I use only 12% (4C) and the engines run MUCH better with a noticeable increase in revs.

Downside: expensive. Upside: smoother running and virtually no mess.

And yes. I have used castor before synth was available. 9% only - again for 4C engines.

I totally agree that synthtic lube is definitely better for 4 strokes.
avijit

finally got to 'break in" the reconditioned engine.
\Had a short flight 5 min or so with the engine mounted on a high winger. went off okay.
Was planning to do RPM readings, but the carb wasn't properly tuned at the low end.
the fact remains that the plane flew
regards,
Avijit

I saw the locally chrome plated engine run and fly. The sound and the way it looked pulling the craft in the air looked convincing. The major issue which we need to see is how long would that chrome layer remain attached and how long it takes to wear off.
My guess is that even if it runs for around 30 -40 flights at the given cost it is much more recommended that a new set of cylinder piston.
Eventually the con rod big, small ends and finally the shaft itself would start to show wear, where you would need to replace them and at this point the cost of reconditioning would no longer be attractive

dear avijit sir,

i think you need to break in the engine again. Atleast for half an hour. I have always seen the vehicular engines require to be broken in when a piston is changed, or when a chrome plating is done to the block. May be it it improve your engine performance.

Abhay

Avjit

Just verify from your guy that it was "hard chrome" plated. It should be, more than likely.

Agree totally with you. we did about 20-25 mins on the ground before the first flight.
regards
avijit