Judging buggy engine temp?

CantThinkOfANam

Hi all,

I kinda new to these nitro engines and I am currently trying to get my engine tuned properly. One thing that I am afraid of is running the engine too lean.

The settings I have now seem to be running the engine nicely in terms of speed and acceleration. However, somebody told me recently that I should be able to place my hand on top of the engine without getting burnt. I can place my hand on it but not for long.

How do you judge the temperature of the engine and make sure its not too lean?

There is a puff of smoke from the exhaust when I rev it.

Thanks for any hints.

seamus-2k7

I heard some people mention that spitting on the engine and see how long it takes to boil. 1 second too long, 3 seconds ok.

As for smoke it should be blue-ish. If it is white the engine is too lean.

hope this helps

T-Maxx

Start with a slightly rich high-speed-needle setting (normally this would be the factory default setting) and slowly lean it out (depending on the make of engine, clockwise 1/8th turn). You will notice an increase in top speed performance as you do so. Continue doing this untill there's a decrease in performance, then richen the setting slightly back 1/8th turn. Remember to chech the LSN as well. (Often beginners have the low-speed-needle too rich and the high-speed-needle too lean.)

If you're inexperienced, smoke will not tell you anything since you've no reference point. Don't look at the smoke - the engine will always smoke because the fuel has oil in it.

CantThinkOfANam

Thanks for the replies. But just how hot should the engine feel? I cant put my hand the on top of the cooling block, does this mean the engine is too hot?

Thanks again.

FuzzyWuzzyWazza

just drop a little water on the top of the head, if it bubbles then it is too hot/lean. But you would be better off with one of these TBH.

CantThinkOfANam

Okay so I tried this water test. If I put water directly onto the top the cooling block it just sits there. But if I let some water down onto the glow plug it sizzles and quickly evaporates.

What ye think?

FuzzyWuzzyWazza

Sounds like it is fine to me, the cooling head is doing its job properly if you get that result. If the engine is too hot then the head will overheat too.

CantThinkOfANam

Cheers thanks for the help.

lotus791

all engines are different no 2 run the same .personally i dont tune by temp . tune by smoke . at the fastest part of where ever you are running you should have a tiny mist of blue smoke just before you lift the throttle ... and to prove the point when i used os and check the temps they where over 320f when tuned right RB engines when tuned where at 260f and the GRP ones im using now seem to run at 180f.... i only check the temp out of interest ...when you think you got it right richen the needles by 2 hrs (imagine a 12 hr clock ) if it smokes and feels responsive and idles like it should without holding a high rev your there . also look at the plug for tell tail signs if the wire is white or out of shape slighlty richen the engine .

coolwings

Lotus is correct .. .the temperature on the outside of the engine casing will vary greatly.

Tuning is a different thing. The inputs are carb settings, fuel intake, air intake, and engine performance on current settings. After an informed decision based on these and only these factors - the output is new settings and different engine performance.