CRRC Pro GF26I

[robertp17]

There is no such thing as "preset" from the factory. How do you know you were not lean on the high end and the thing detonated itself to death? Im not defending these engines, personally I dont own any chinese engines but im just saying that what happened with you could have happened with any engine if it was set too lean.

[Doublesixes]

The engine quit in mid air and it was not your typical deadstick. There was an ominous dry click noise that could be heard.
I removed the cylinder head and the ring was basically out of its groove. A ring should have both ends lined up with the small hole in the piston as to prevent rotation. In this case the ring had rotated beyond that point.
I never adjusted any carb settings as they are preset at the factory and it seemed to work fine until the episode I just described. There was another flaw in the engine and it had to do with the Hal sensor connector with the CDI box. I had to re-solder the whole thing to get a consistent spark.

[rcign]

The small hole in the piston is there for a pin that keeps the rings from turning in the piston and ending up in a port...Sounds like the pin in your piston either came out or was never in....the ring turned and got caught in a port, stopped the engine, probably destroyed the piston and cylinder....

[Doublesixes]

Rcign, I believe your diagnostic is correct. The engine turns but there's not enough compression. I used a high torque electric starter and I couldn't even get a single pop. The engine is dead and it only took just under a gallon. Kinda frustrating.

[zoomer260]

On my latest gas engine a DL 50, I had to OPEN the high end needle to get more rpm. About 200 more ! This told me it was very lean from the factory.

Even though this is the first time I ever richened a factory setting to get more RPM makes me a believer to always check.

Either way the factory settings have never been "right on" for my location and fuel mix.

I should note I've only owned about 10 or so gas engines (model) so I am far from any kind of expert.

[rcign]

If the cylinder isn't destroyed the piston and rings from a Zenoah or Chung Yang 26 will fit..I have one of the 50cc twins here, same exact cylinders...The piston from a G26 looks to be a perfect fit...
I can probably fix it for about $40 plus shipping if nothing else is bad.....

[Doublesixes]

rcign, I'm having someone around here have a go at it. If that person fails, I accept your generous offer.
66

[robertp17]

It is possible that the pin came out. I had it happen once to me on a 2 cycle motorcycle and it is not pretty. In my case the pin popped out and somehow snagged on the exhaust port. How can it even come out unless there is to much piston to cylinder wall clearance? This is a manufacturing defect correct?

[rcign]

There are two types of pins and 3 ways to install...
One pin is centered in the ring groove, G26 thin ring type..the ends of the ring fit over the pin..
The other two are halfway in the groove and halfway in the piston..The ring has a quarter round shape on the end and almost touches together at the ends and fits under or over the rest of the pin..
Most of these have the pin in the top half of the groove, but a few are in the bottom...Works the same either way....
Some pins are long enough to go all the way through the piston wall and can be seen on the inside..Most are just a tight press fit in the piston...
The clearance between the piston and cylinder wall should be 2 to 3 thousandths..The pin would have to be really loose and short to fall out...

[Doublesixes]

I'll see if I can get some pictures to show the piston, pin and ring. One thing I'm certain of, the pin doesn't go all the way to the outside of the piston and the ring is way too loose and rotates freely, even over the pin area. Something is really wrong.

[robertp17]

It should rotate freely in the groove when its not compressed. Put it back in the cylinder and look thru the exhaust port and see how much up and down movement you have between the ring and piston. If its a sloppy fit then maybe that would explain why the pin came out.

[rcign]

The pin should not be flush to the outside of the piston...If the ring rotates over the pin it's not sticking out far enough to engage the ends of the ring...With the ring on the piston and in the cylinder there is only about .005 between the ends of the ring, and it can't move back and forth over the pin..

[2robinhood]

Ran some more props today.
I didn''t tach the Xoar 17 X 6, but performed good.
APC 17 X 6 - 9,200 rpm performed the BEST.
APC 18 X 6W - 8,050 rpm a little less performance the the 17 X 6.
The APC 17 X 6 was the best in my Seagull Laser 200 which weights 11 lbs 2 oz.

[flymoor]

Start again, accidently bumper the wrong key, anyway I crashed an extra that had been crashed and given to me, and missed a defect in the right stab on my rebuild. My GF26i works great well did, until the tail feathers blew apart in the sky. Had only one servo for tail and she went straight into the ground did not have time enough to kill engine. Result great prop strike and other damage to engine, plane destroyed, radio ok so far on tests. Anyway am trying to figure out how to pull the prop driver from crank, so I can inspect replace crank Made a puller out of aluminum bar and drilled a couple of holes in prop driver face, 10-32 threaded pulled , heated pulled did not move , the aluminum bar did, not heavy enough and finally pulled threads out of prop driver. If you have a great way or not so great way of pulling the same would be glad to hear from you
Rich

[flymoor]

Well my son in law took one look at the schematic of the engine parts and said did you try screwing off the pro p bolt from the crank, I said I don''t think you can do that without pulling the pro p driver first. He said do you have two nuts, I said yes. We went out to the shed put two nuts on it and screwed off the pro p bolt which locked the pro p driver on the shaft. Then simply used a dowel and hammer and one tap on the crank and it was out of the case. duh!!

Well maybe this post will help someone else. The crank was badly bent. Will have to be replaced, and I will hear about this for quite awhile from my son-in-law.

Rich