Toro1

My Feedback: (2)

Do you hard core norvelites know if norvel sells just the con rod for ame 061 ? or the latter is to purchase new head/piston/sleave set up. Also, Im not a huge 1/2a guy but decided to try one for diversity. A quickie 200 w/ unthrottled AME 061 makes for some interesting speed conversation. I had about 2 weeks of flights on it, broken in, or fairly well at least I thought, and I switched over to the higher norvel nitro fuel. I think it was 30/35% synthetic. I probably got about 4 tanks through that and on the 5 th flight BLAM !!! con rod failure, but the airplane was smokin'. My question to you is too much nitro ? 5.5x4 prop ok ? or just plain ignorance on my part.

Larry Driskill

Well, I'm not a hard core norvelite, but I have used them. And I am very hard core 1/2A (and 2nd Amendment and free enterprise) so I will answer as Hard Core albeit not Norvel.

Yes, an .061 rod retails for $3.89. I have changed several of them. You have to get the wrist pin past the crimp and then re-crimp over the pin when you have the new rod in place. Not too difficult. If you get to that point and want some tips on doing it several of the folks here can help. I will throw in my technique then too.

I think 35% nitro is probably OK, but I always use at least some castor. I have found 30% nitro and 20% castor makes good power, has lots of needle latitude and generally makes for a longer lived engine.

Look at the top of your piston and make sure it was not hitting the head. Make sure you have good oil and enough of it in the fuel. I suspect Norvel fuel meets that criteria. Be aware that the engine is going to wrap up tighter in the air than on the ground and can pick up considerably more RPM in a dive. I have turned the AME .049 well over 30,000 without breaking bits, well without breaking bits too often. I would expect a 5.5X4 to keep you in that range or below. . . except maybe in that dive. . . And, if the engine is over reving, then you have the power available for a little more pitch that will pull your jet even faster.

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combatpigg

My Feedback: (3)

HI 1-26 DRIVER! The 4 pitch prop makes the load on the rod pretty high, and if you go into high speed dives that's the straw that breaks the camels' back. I know that you need a 4 pitch to go fast, but maybe less diameter would put you under what ever the load limit of these rods is. A 4.5 diameter decreases the load factor by 50%.

Toro1

My Feedback: (2)

Thanks for the info, I may just replace cylinder/piston and call it good, will also replace rod and save that one 4 a spare.

Thats the stuff Im looking for thank you guys.

J

Jeff Leavitt

26driver,

Where did the rod break? If the break is right where the rod enlarges to form the crank journal, I 'm inclined to think lubrication was the problem. I've had the same thing happen to me, but never when I was using fuel with 20% castor for lube. If the rod grabs the journal under power, the rod will quickly fatigue and break as I indicated. Look at the crank journal and rod with a 10X magnafying glass you'll see some interesting stuff. Patch that baby up and have some fun! Rgds, Jeff

Japanman

Norvel may fix that under warranty...

J.M

Toro1

My Feedback: (2)

Jeff it broke on the lower crank journal probably about 2/3 up around at the connection right where you said it would be. It also looks like the piston is lightly scored, so I think a TEOH is up. Thanks for the info, and Ill put that castor to use.

J