The new unofficial CRRC engine thread!
04-12-2010 | 05:52 PM
#1
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From: pleasanton,
CA
The new unofficial CRRC engine thread!
Hey all you CRRC owners, this is (I hope) going to be the new CRRC owners thread for every one who has questions or suggestions. Please post here. I just got my first CRRC up and running, and all I can say is that I am IMPRESSED!
04-13-2010 | 07:55 AM
#2
RE: The new unofficial CRRC engine thread!
Great idea to start this thread.
I too have a fairly new CRRC 50i Pro. It's a powerful motor that starts easlily and runs great. I have one small issue with it, though. Lately I had the first dead stick coming in for a landing. The motor cut off as soon as I throttled back to idle. When I picked up my plane I found the prop stuck. My first reaction was I have a seized motor. I disassembled the motor right at the field and, to my amazment, found absolutely nothing wrong with the internals. Everything was nice and shiny. As a matter of fact I was very pleased with the workmanship of all the machined parts. Then I found the problem. The crank has a little too much lateral play and can be pushed rearwards about 1/32". Now, this motor does not have a candilever type crank. It is supported by three bearings. That's why she runs exceptionally smooth. When the motor is hot from running, obviously the crank is being pushed back by the braking effect of the slow rotating prop, when the throttle is cut back to idle. Consequently the prop hub hits the crank case and rubs aginst it, which makes it feel like the engine suffered a piston seizure. A slight wack forward on both sides of the backside of the prop frees up everything and the motor turns smoothly again. I tried to pull the hub off the crank, but is is glued on with red Loctide and I sure don't want to heat it up to soften the Loctide. It would, most likely, destroy the magnet that's inbedded in the hub. So I tried to stick a piece of 120 grid Wet -n Dry between the hub and the case and run the motor with a starter motor, with the plug removed. The first flight after this fix was positive. No rubbing. But I still want to prevent the crank from moving axially. Other than this little problem I like this engine a lot.
I too have a fairly new CRRC 50i Pro. It's a powerful motor that starts easlily and runs great. I have one small issue with it, though. Lately I had the first dead stick coming in for a landing. The motor cut off as soon as I throttled back to idle. When I picked up my plane I found the prop stuck. My first reaction was I have a seized motor. I disassembled the motor right at the field and, to my amazment, found absolutely nothing wrong with the internals. Everything was nice and shiny. As a matter of fact I was very pleased with the workmanship of all the machined parts. Then I found the problem. The crank has a little too much lateral play and can be pushed rearwards about 1/32". Now, this motor does not have a candilever type crank. It is supported by three bearings. That's why she runs exceptionally smooth. When the motor is hot from running, obviously the crank is being pushed back by the braking effect of the slow rotating prop, when the throttle is cut back to idle. Consequently the prop hub hits the crank case and rubs aginst it, which makes it feel like the engine suffered a piston seizure. A slight wack forward on both sides of the backside of the prop frees up everything and the motor turns smoothly again. I tried to pull the hub off the crank, but is is glued on with red Loctide and I sure don't want to heat it up to soften the Loctide. It would, most likely, destroy the magnet that's inbedded in the hub. So I tried to stick a piece of 120 grid Wet -n Dry between the hub and the case and run the motor with a starter motor, with the plug removed. The first flight after this fix was positive. No rubbing. But I still want to prevent the crank from moving axially. Other than this little problem I like this engine a lot.
04-13-2010 | 11:30 AM
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From: pleasanton,
CA
RE: The new unofficial CRRC engine thread!
Another thing I know about these engines is that they do not like to stay at idle for too long when using a wood prop, because the wood does not have enough mass to act as as a flywheel for this engine for too long.
04-13-2010 | 06:15 PM
#4
Senior Member
RE: The new unofficial CRRC engine thread!
ORIGINAL: thevirginian
Great idea to start this thread.
I too have a fairly new CRRC 50i Pro. It's a powerful motor that starts easlily and runs great. I have one small issue with it, though. Lately I had the first dead stick coming in for a landing. The motor cut off as soon as I throttled back to idle. When I picked up my plane I found the prop stuck. My first reaction was I have a seized motor. I disassembled the motor right at the field and, to my amazment, found absolutely nothing wrong with the internals. Everything was nice and shiny. As a matter of fact I was very pleased with the workmanship of all the machined parts. Then I found the problem. The crank has a little too much lateral play and can be pushed rearwards about 1/32". Now, this motor does not have a candilever type crank. It is supported by three bearings. That's why she runs exceptionally smooth. When the motor is hot from running, obviously the crank is being pushed back by the braking effect of the slow rotating prop, when the throttle is cut back to idle. Consequently the prop hub hits the crank case and rubs aginst it, which makes it feel like the engine suffered a piston seizure. A slight wack forward on both sides of the backside of the prop frees up everything and the motor turns smoothly again. I tried to pull the hub off the crank, but is is glued on with red Loctide and I sure don't want to heat it up to soften the Loctide. It would, most likely, destroy the magnet that's inbedded in the hub. So I tried to stick a piece of 120 grid Wet -n Dry between the hub and the case and run the motor with a starter motor, with the plug removed. The first flight after this fix was positive. No rubbing. But I still want to prevent the crank from moving axially. Other than this little problem I like this engine a lot.
Great idea to start this thread.
I too have a fairly new CRRC 50i Pro. It's a powerful motor that starts easlily and runs great. I have one small issue with it, though. Lately I had the first dead stick coming in for a landing. The motor cut off as soon as I throttled back to idle. When I picked up my plane I found the prop stuck. My first reaction was I have a seized motor. I disassembled the motor right at the field and, to my amazment, found absolutely nothing wrong with the internals. Everything was nice and shiny. As a matter of fact I was very pleased with the workmanship of all the machined parts. Then I found the problem. The crank has a little too much lateral play and can be pushed rearwards about 1/32". Now, this motor does not have a candilever type crank. It is supported by three bearings. That's why she runs exceptionally smooth. When the motor is hot from running, obviously the crank is being pushed back by the braking effect of the slow rotating prop, when the throttle is cut back to idle. Consequently the prop hub hits the crank case and rubs aginst it, which makes it feel like the engine suffered a piston seizure. A slight wack forward on both sides of the backside of the prop frees up everything and the motor turns smoothly again. I tried to pull the hub off the crank, but is is glued on with red Loctide and I sure don't want to heat it up to soften the Loctide. It would, most likely, destroy the magnet that's inbedded in the hub. So I tried to stick a piece of 120 grid Wet -n Dry between the hub and the case and run the motor with a starter motor, with the plug removed. The first flight after this fix was positive. No rubbing. But I still want to prevent the crank from moving axially. Other than this little problem I like this engine a lot.
04-14-2010 | 07:11 AM
#5
RE: The new unofficial CRRC engine thread!
pe reivers,
I don't think the engine gets too hot during flight. After a flight I can touch it with my fingers and don't get burned. I also can move the crank back and forth when the motor is cold. I firm tab on the spinner and it slips to the rear. I whack on the back side of the prop and she pops forward. I think the crank slides baock and forth inside the bearings. I need to investigate.
I don't think the engine gets too hot during flight. After a flight I can touch it with my fingers and don't get burned. I also can move the crank back and forth when the motor is cold. I firm tab on the spinner and it slips to the rear. I whack on the back side of the prop and she pops forward. I think the crank slides baock and forth inside the bearings. I need to investigate.
04-16-2010 | 07:01 AM
#7
RE: The new unofficial CRRC engine thread!
Yesterday I had my engine apart, again. Sure enough, there is excessive axial play in the crank. Almost one millimeter. There is no movement of the bearings when I push the crank back and forth. They still seat tightly. I believe there is too much play between the rear counter weight and the rear bearing allowing the crank to shift. I suspect, when the motor gets warmed up it loosens up, allowing the crank to move backward when the throttle is cut back to idle in flight. The prop is acting like a brake when the airplane slows down. I wonder if I could place a thin washer where the back end of the crank slides into the rear bearing, acting as a shim? What is your opinion, pe reiver?
04-16-2010 | 07:09 AM
#8
Senior Member
RE: The new unofficial CRRC engine thread!
If you can make a shim that reduces play to about 0.05mm, that would be fine. Do not take out all play, because there will be no way of knowing just how much pretension you put on the bearing, and the crankcase will expand more than the shaft, for which the front bearing must compensate.
04-16-2010 | 11:35 AM
#9
RE: The new unofficial CRRC engine thread!
Thanks for your input, pe reivers
I know I can make a washer just thick enough to eliminate most of the play. I was thinking of even more than 0.05mm. Probably more like 0.1 - 0.2mm.
I know I can make a washer just thick enough to eliminate most of the play. I was thinking of even more than 0.05mm. Probably more like 0.1 - 0.2mm.
06-17-2012 | 01:20 PM
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From: Panama, PANAMA
RE: The new unofficial CRRC engine thread!
Hello, I am just starting to have troubles with my CRRC GF50i gas engine.Actually, I can't get more than 6000 rpm with a 20x8 wood propeller, ( brand new engine and after 3-4 hours of use, I got about 7300 rpm with the same 20x8 wood propeller);I got clean the whole carburetor, checked all fuel tank system, tygon lines, needles adjustments, spark plug, fuel-oil relationship, but no results.What I found as it has been recorded on my GoPro camera is a last flight in which the engine starts to sound like loosing power as the flight progress, and then the engines quits so I had to make a dead stick succesfully landing without any damage.When I walked to the airplane I found the engine to be very hot and since then my rc club fellowmates and some research about this engine points to a bearing set issue that leads to those common symtoms.What I planning to do is change the bearing set for this engine, so I wanted to share my experience with this CRRC 50cc gas engine, which it is a powerful one, but looks like manufactures does not take care on the bearing set.I have had this engine for about 2 years and flown it about 22-22 hours.
I would appreciate if someone could lead to a place in order to buy a good quality bearing set for this engine, and also any graphic or photos guides or instructions in order to open the engine and replace the bearings, with you experience and/or suggestions.
Thanks, Schaye G.
I would appreciate if someone could lead to a place in order to buy a good quality bearing set for this engine, and also any graphic or photos guides or instructions in order to open the engine and replace the bearings, with you experience and/or suggestions.
Thanks, Schaye G.
