engine overheating

[danthemancarolina]

I have an old os xs46 heli motor. dissasembled, cleaned carbs and block bearings etc. I can get it to run and even hovered. But after about 2min of run time she is cooking! This engine I used in my plank for a long time and it never ran hot. I thought was too lean, richened it up and wont even stay running. richened up the low idle and that helped a bit. I have used the techniques from the raptor site. Now I am just plain frustrated, wondering if something other than the motor is making it heat up....

[ghtracey]

Is this a heli engine? I can't find the model on the net, but if its a plank engine it has much less cooling area than a heli engine and will most likely always run way too hot.

Other things to consider maybe:
- air leaks in the fuel system?
- what % of oil is in your fuel, oil content makes a big difference to heli cooling

[derrill84]

Here is a photo of an OS46H The H is for Heli. Is this what your engine looks like?
49554

[danthemancarolina]

My engine is a Heli and looks like the picture posted. I just used it in a plank because at the time it had more power than a 40. As far as fuel, I opted the cheap rout and bought 15% I read other folks use it just fine. I believe the fuel is cool power.

[derrill84]

What pipe are you running? What temperature is the motor getting to?

[danthemancarolina]

I am not sure of the pipe. Dont think its anything fancy. It is chrome though. It was on a hyper50 that came with the heli. (I screwed up the piston on it and waiting on replecement). Thats why I revived my 46

[Raven_darkcloud]

You might try looking for an issue with the fan. Also 20% might fix some things too.

[Coop]

Air, fuel, and oil cool the engine. You can't control the air easily. Increase the mixtures both low and high. Use heli fuel which is at least 22% to 24% oil. I use 15% all synthetic Cool power with 18% oil(plank fuel), then I add 3.4 oz per qt of Sig Klotz syn oil to it. I do this because I use the same fuel in my planks. My OS 50 runs cool at 160 degrees to 190 degrees. I do run it quite rich, however since I only hover and pretty much fly scale. Don't under estimate the amount of cooling conributed by oil in an air cooled engine. It gathers heat and spews it out the exhaust.

It's helpful to note that the low speed screw affects mixture well above idle, on some engines well into hover power.

[danthemancarolina]

Ok, well the fan might be some problem. I noticed after i vapor locked the engine. the fan moved up, found the fix on raptortechnique. sure enough, the fan screw let loose. but i noticed alot of black plastic pieces on the table where i was trying to start it. maybe i do need another fan even though it looked fine. maybe its slipping around the shaft and not cooling. I will also get some of the sig oil and add it to the fuel. I didnt realize that 30% fuel had more oil. I thought it just had more nitro to burn. Its all a learning curve...thanks for the insight fellas!

[Coop]

30% nitro DOES NOT necessarily have more oil. Fuel designated HELI fuel has more oil! Some brands tell you the percentage of oil some don't. Plank fuel seems to be in the 18% range for oil, not enough for heli use. The reason is for better cooling. You can find 15%, 20%, 30% nitro heli fuel, it will have a higher percentage of oil...in the neighborhood of 22% to 24%.

[bradh1963]

same thing happened to me and when the fan moved up the bearings in the frame were all crushed so bad you could hear them over the motor. Had to replace the two bearings

[vandelescrow]

try making a baffle for the inside of your fan shroud, to bring it closer to the head of the engine. The R90 comes with one: see attached photo taken from the R90 manual (part 4 in the pic), it is also shown here http://www.heliproz.com/prodinfo.asp?number=133045, just a flat piece of plastic bolted to the inside of the shroud.

[danthemancarolina]

Thanks alot fellas. I will take the fan off and see if its bad. Also check the bearings. Would that be the bearings inside the fan unit itself? If I order a new fan, does it come with bearings or do I have to order. Thanks p.s. who has the fastest raptor shipping?

[awr]

I had the same engine in my Raptor 50 - now using the Hyper.

I was running 30% nitro in my engine. More power and it runs cooler. It's also easier to tune the engine.

Pick up a quart/litre of 30% and give it a try. If your carb is set correctly, you should see a noticeable decrease in temperature because the engine isn't working as hard.

Wayne

[iher]

I have the same engine on my old shuttle zx.
I had a lot of overheating problems with it....ended up scratching the piston a bit.
But now it works like a charm after changing to 30% nitro, new plug, and a fan shroud that I modified as AWR says , channeling the air and forcing it through the grooves of the head, by extending the shroud wall all the way through the top and sides of the engine head.
starts imediatly, never overheats and has power to spare even for hard 3D ( ok not "pro " 3D , but pretty demanding powerwise)