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Engine basics => Engine set up tips => Topic started by: JamieHolford on September 19, 2010, 06:16:14 AM
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Hi yall!
I recently bought a Cox Golden Bee from a friend in quite good condition. It came with a brand new spare Cylinder with piston. This extra cylinder is dual ported ( 2 slots ) while the cylinder already on the engine is single ported ( big slot type )
Which would be better for performance in yall opinion? Im sure it would run fine. Im not looking for a major powerhouse but I dont want a dud either.
I have the dual ported cylinder with new piston on hte engine now. I plan on running it monday at some point.
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The dual port is going o have more pwoer for sure. I also bored the carb on my golden bee out to black widow specs.
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The dual port is going o have more pwoer for sure. I also bored the carb on my golden bee out to black widow specs.
How big is the black widow venturi?
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I forgot I'll have to check I had one to measure. And just matched it.
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When you say ports, do you mean the exhaust slots, or the bypass ports cut into the inside of the cylinder liner?
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Exhuast on the outside lol. Ima have to check the cyclinder just to see if the bypass ports...... Im still learning as I go hehe
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One thing to keep in mind, the Golden Bee came with a variety of cylinders. I myself like the dual ported cylinders as you get more power out of them , but the single ported runs very well too. You get a lot more fuel economy out of the single bypass models and they will fly the model well if built light. As for boring out the venturi, be careful here as you can go overboard and the Black Widow engines were all over the place in sizes throughout the years. Larry Renger stated that .093 is pretty much the max and is about what the Venom came stock with. I'd personally try to keep it under that size as fuel draw won't be sacrificed as much and easier needling is a result. A Cox high performance head will give you much more power or a Galbreath Nelson set up but that will require some tinkering with a lot more head gaskets. The Galbreath may require 4 or more gaskets. Ken
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I pulled the cylinder off a little while ago and it is indeed dual ported. I reckon this is a good sign!
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Yeah the widow I copied was a little smaller than .093 I thing it was .089 but I won't swear to it. As far as heads go I have a setup from Merlin for 15 bucks you get three plugs and the head. I'm using three head gaskets to make it easier to start and tune but two might be fine depending on the engine.
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What and who is this Merlin you speak of ? :)
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http://merlinglowplugs.com/Aircraft.html use Part # 2019a. Remember you have to use probably three head gaskets. This head might not work all that well with a single transfer port cylinder. The other guys may have tryed this and can tell you more. I've only used it on dual port engines.
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http://merlinglowplugs.com/Aircraft.html use Part # 2019a. Remember you have to use probably three head gaskets. This head might not work all that well with a single transfer port cylinder. The other guys may have tryed this and can tell you more. I've only used it on dual port engines.
Fewer gaskets (spacers, really) if you're running lower nitro. Cox engines seem to come alive with higher compression heads, although they will blow plugs more often that way.
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Good point tim. I always start out high then work my way down. Cox's will bend rods if I get too excited lol.
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Nathan, the Merlin set up does work and well I may add. The one I own has the red insulator around the button. I'm assuming this is color coded for temperature reasons. This would tell me its in the hotter range but I'm using high nitro with mine. I'm running 40% nitro in a Tee Dee with that set up. I had to use 5 head shims. The engine had too much compression and would almost pre detonate. I wouldn't be surprised that you would have to add additional shims compared to the stock Cox head when using the Merlin plugs. I've had some real screaming lean runs with the Merlin head and so far they've held up. Ken
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Fair enough. I haven't tried one on a TD. I run the hot ones as well. Three shims is just about right with 25% fuel. Cox engines are too much fun it's a shame I never got into tether cars.