DarZeelon

Gene,


It is obvious your technique is OK, for both types of engines.

I don't know who makes TS/Kangke engines, but I believe they use CNC machined parts.

This usually means you can take batches of 1,000 of each part, take one of each and they should all fit.

Do both engines use the same con-rod? Could it be a complete defective batch of con-rods, or crankshafts?
Is the crankshaft one-piece, or is the crank-pin pressed in (like some GMS engines)?

If it is one-piece, is the crank-pin machined on-center (expensive), or off-center (cheaper)?

The only time I lost a rod was when an HB I had broke its crankshaft, upon trying to electric start a hydraulic-locked engine, some 24 years ago...

Gene Chernosky

My Feedback: (182)

Dar...first of all...THANK YOU...for yet another expert's opinion on this matter.

I'm not sure if they use the exact same rod, but the strokes are the same on each displacement. The crankshaft is a one-piece design.

Speaking of wear pattern...I did notice that it seemed to be on the front top of the lower rod bearing where the wear was concentrated. It left a slight rim, I guess you could call it, on the back side of the rod bearing at the top. The crankpin does have a slight chamfer on the end that could have left this. OR...maybe there is another part at fault here.

It's going to be bench-ran through at least two full 8 oz tankfulls at full throttle two or three clicks off of full lean today with an APC 11x7, 10% nitro fuel and an OS #8 plug. If the engine doesn't prematurely wear-out, I'll keep it...if not, Kangke gets the whole thing back with the expectation of a FULL refund this time. I'm tired of fooling with what has initially appeared to be JUNK! ...hopefully it redeems itself today.

Hobbsy

My Feedback: (102)

Gene, since this about rods, I had an unusual experience yesterday, I got a used Fox .50, apparently an early one as it has a pin holding the wristpin in place, it's the first engine that I've ever been able to feel a wear ridge at the top of the cylinder where the piston ring stops and yet it has excellent compression. The surprise was that the crankpin is worn down instead of the rod, the rod has no oil holes drilled in it like my later .50s and .46. A new crank is on the way, I already have a new sleeve and piston, lucky because Fox is out of sleeves for the .50. This engine obviously has a lot of run time on it. It has the spinner back plate that goes right on the collet.

DarZeelon

Gene,


Thank you for the appreciation.

It seems, the manufacturers want to reduce cost at all cost...

Magnum (Sanye) made the .52XLS a good engine, until they acquired a batch of cheaper bearings...
Ernie Misner ran into the bad batch...


The only way to achieve good quality control, in CNC production (all parts are the same), is to assemble a few such engines, from each batch of parts and to run them for several hours, in varying conditions, props and fuels, disassembling and verifying there is no measurable wear and no wear pattern that could signify a mis-fit.

Only afterward should this batch of parts be used in production.

Failure to do so may result in large batches of returned engines, that would be non-economical to disassemble, replace the defective part(s) and reassemble. A sunk cost.

While the cost of a model, two-stroke engine, FOB China factory, is $5-10, the whole batch of 1,000 is $5,000-10,000, while the costs for two days of testing is $20-50, including pay and the fuel...


I would also seek a full, unconditional refund, in your situation.

Turk1

Pls be sure the replacement conrods r the right parts.I mean the length of conrod.Once my buddy purchased a sleeve and piston set for his heli OS 46 and conrod was longer than original in the coming set.Did u measure or check the stroke before mounting the head?

Gene Chernosky

My Feedback: (182)

It made it past the 'test' runs. It was taken to full lean, ~12K, and backed down to 11.8K and then ran through two 8 oz tankfuls at full throttle, cooling inbetween runs. Afterwards there were no unusual 'clicking' sounds, etc., coming from the engine so I can assume it will 'go' for a while. It does have a two year warranty so I need to get it airborne ASAP to put it to the real test. Should it 'fail' again it will be documented here on RCU.

For now, this 'issue' can be 'put to bed'.