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-   -   3w 106 TOC problems (http://www.rcuniverse.com/forum/gas-engines-142/6224217-3w-106-toc-problems.html)

edgreenlee 08-11-2007 10:03 AM

3w 106 TOC problems
i own a broken in (but low time) 3w 106 toc motor with standard mufflers....(i also own a da100 and the 3w has always out performed it)...to make a long story short, the motor was crashed. i sent it to cactus aviation for repair...the verdict --- no broken fins, no bent crank....broke the carb block - replaced...(broke one muffler which i had re welded)...motor said to be checked to run fine....i get it back and put it on a new plane with a 3w 27x10 prop and premium gas.......idles good, transitions good...top end is poor...vertical performance not good.....i put a tach on it and adjusted the high end until it started to sag......backed it up a bit...the most i can get out of it is 6000 rpms.....called cactus - they said the timing might be off....sent it back to cactus....the put new gaskets in it and decarboned it....sent it back....same situation ...only turns about 6000 rpms.....(my da turns a 27x10 6400 rpms)...i have adjusted the timing until im blue in the face...cant get any more out of it.....cactus says "they may have put new rings in it - but cant remember" of course, that would require some running to get more out of it........but it wasnt on the invoice..........the motor looks good - the pistons are nice and shiny - new looking......turns over smoothly....great compression.....any ideas? ive thought about selling it "as is" to someone who knows how to adjust motors better than me...but i thought i would get some ideas from you guys for "one more try". thanks for your suggestions and input

Buzzed 08-11-2007 11:44 AM

RE: 3w 106 TOC problems
Did Bobby test run this engine with your ignition module?? The reason I ask is that we have seen RPM changes with different modules. I suspect some may have timing circut issues from one to the next..If you can get ahold of another module try it and see if the issue stays the same..Buzz

edgreenlee 08-11-2007 01:32 PM

RE: 3w 106 TOC problems
thanks buzz/......im assuming he ran it with my ignition - i sent it with the motor....he says the motor runs strong....but they obviously didnt tach it

celby54 06-30-2008 05:24 PM

RE: 3w 106 TOC problems
hi I have a 3w 106 comp also I am doing good to get 6000 with a 27x10 TBM wood prop. I have a similar situation with my engine. I bought it used it didnt run right so I sent it to Aircraft International they raplaced the woodroof key hub bolt carb block plug wire ends and ignition base plate. Said it runs strong and sent it back to me. now i am having a problem with the engine cutting out when the plane is moving or rolling or climbing. On the ground restrained its just fine but when I go to take off just before lift off it will cut out . Scarry huh I dont know what to do. All i can seem to get out of it is 6000 rpm too.

JeffH 07-01-2008 09:18 AM

RE: 3w 106 TOC problems
wow, maybe I shouldn't have gotten rid of the one I had. I had a well used 106 TOC that turned a Biela 28x10 at 6600 peaked.

Ih82crash 07-02-2008 08:46 AM

RE: 3w 106 TOC problems
I have a 3w 106 that used to run great when on the ground transition was great and everything. whenever I would roll to knife edge or inverted, it would sag or die. I ended up fixing the problem by leaning the high side ever so slightly. It took about ten takeoffs and landings to get it right, but finally did and now I turn a vess 27 a at about 6700.

smokin 07-08-2008 04:14 PM

RE: 3w 106 TOC problems
this gurgle at knife or inverted is not to be fixed with the needles!!!!!!!

the reed block needs changing..... the std reed block is plastic and it doesn't allow the fuel to burn evenly with the rest of the engine as it retains heat differently. the newer aluminum block from AI will do the trick.

right now you have excess unburnt fuel being dumped into the cylinders when going to KE or INV. the plastic reed block will get up to temp a few minutes into the flight and this will happen less and less. i would assume that you are tuning the needles between flights and the engine is getting warmer and warmer....thus eliminating the issue. the needle adjustment isn't what is fixing you issue...heat is.

the alum block heats up at the same rate as the rest of the engine therefor there is NO extra unburnt fuel getting dumped into the engine at KE durning any part of the flight!!! it is about a $40 or so fix and VERY easy to do!!!!!

make this adjustment and you will have the best 100 class engine out there!!!!!!!!!!


jon595 07-08-2008 06:11 PM

RE: 3w 106 TOC problems
There is a newer version of the aluminum reed housing. Cost is $65 shipped from AI. It is cast, moves the reeds closer to the crank, and appears to have less internal volume so that fuel puddling (burbling during rolls) will be a thing of the past. If you go this route check your carb mounting block for warps. I'm waiting on mine.[:@]

I tried a NX prop on mine (28x10) and it was not happy with it. Went back to a Menz of the same size and the top end was back as before.

altavillan 07-08-2008 07:46 PM

RE: 3w 106 TOC problems
I lean toward the ignition being the culprit. I have a backup 3W ignition with the exact symptom. My suggestion is to get a CH unit or RCXL, either way CH sells them both. Piece of cake to mount a CH unit where the 3W ignition mounts and change the timing. You'll spend months sending parts back and forth to Cactus and not get anywhere. A phone call and a few days later you'll have it singing again. CH ignitions wear out too, none of mine last much more than a year/maybe two, (3-400 flights) before needing work, but when I send them to CH they fix them, charge me whats needed $ wise for the repair and about a week all told later I'm flying again. Usual repair is replace the coils and the spring that contacts the spark plug. Keep your 3W for a backup but just don't trust it. They love to quit working at the worst time.

IanB 07-21-2008 10:54 AM

RE: 3w 106 TOC problems
If your engine has the 3w trumpet on it take it off the trumpet for the 106 has a large lip internal in the trumpet which catches fuel so that any fuel puddling cannot get out of the trumpet ................roll and the engine will stumble...................I did not know about the new carb block but mine ran perfectly after taking off the trumpet........also snugging down the carb bolts may help but DO NOT overtighten

jon595 07-21-2008 05:42 PM

RE: 3w 106 TOC problems
I had already taken the trumpet off. It does catch a lot of fuel, you will see how much when you choke the engine for the first time without it. Ran mine for the first time this past weekend with the V2 reedblock and it has stopped the rpm changes during rolls.

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