Quick question... My Kyosho KE21R has almost a half gallon through it now, and tune is getting easier each time I run it. Why will the darn thing not start without preheating it first? In the house it stays 72f, and it won't start until I get the heat gun out and preheat to above 160f. The warmer it is the easier it is to start.

Check that you have a hot plug to help it start. For breaking in you will loose some tuning ability but the hot plug will help with starting and break in. After that you can work into a colder plug. For a hot use the OS P3. you can use what ever after that.

Thanks. I kinda figured it may be a plug issue. I run Odonnell 30% fuel and Odonnell #99 cold plugs. How long do you thing it will take to get a (normal temp) start up? In years past I ran hot plugs with 20% nitro with zero issues starting (.12-.15 engines).

My guess, (and it differs from engine to engine) is going to be somewhere between 1.5 and 2 gallons when they really start to scream. Don't get in a rush to not have to preheat. It helps the engine life a ton and there is not as much pinch so less wear.

Thank you so much for the great replies. It's getting near the total end of racing season here, but with our temps in the south there will be more opportunity to test and practice. The more fuel I run through it the better it runs. I have to turn my radio down to 50%-60% for my aspiring driving skills. Both the buggy and I will get better in time with more practice and tunes both engine and chassis wise.

I would warn you to be careful with an engine this new to be running it that hard. You will end up snapping a rod or having an engine that will last for only a couple of gallons. Use the engine break-in bible for how to properly break in an engine.

Thanks for the input. When I did my break in, I did a hybrid method from the "break in bible", and what Squirrelrod does on Youtube.
On a side note for newbies and such. I just came in from trying to diagnose my idle problem. It has had a BAD two stage idle and while keeping the idle high to run, I was never satisfied. A combination of things were my problem. Trying to tune with air filter on. (I know this sounds bad, but this time I ran it on my deck aka wheels off the ground). My radio was quite a bit off, and the one of the collets for the throttle servo was out of adjustment. After a twist here and radio adjustment there, I got the two stage out. She idles fine now after full throttle runs. I put the filter assembly back on and ran on the ground and she purrs great, and does what is expected.

What are the running symptoms of a glow plug that is too hot or too cold? How do you read a glow plug to determine where your tune is?

The first post has info on reading a glow plug. I am curious in picking the right plug temperature though. I am looking to get into nitro and this is something I have not seen info on yet.

Like this?




http://www.novarossi.it/2012/index.p.../off-road.html

This is a subject where those that know don't want to talk, for example colder plugs while harder to tune than hotter plugs have a power advantage, coupled with head shim stack you can get lost on chasing the best setup/tune.

Thanks for the links to the charts. Is the Picco P5 TH a hot plug or is it supposed to be used in hot weather? I am assuming a general rule would be colder plug on a hotter day? The head shimming is another thing I havnt seen much on. I know that having the headed shimmed improperly can damage the motor and hurt the performance. I am trying to find some basic info on when I should add/take away a shim or change the temperature of my plug but it has proven difficult.. I suppose that head shimming and trying different plugs is just something that takes trial and error by the user?

You're welcome, I think the 5TH is comparable to a OS P3 or so I read it around here, will use my search-fu and send a PM with the info I find.

Up to 0.3mm head clearance is doable, lower than that and you will have lots of issues with thermal expansion and the piston might touch the plug button/deck (research I did years ago I found 0.36mm to be the safest minimum deck height, an engine I religiously followed that was surprisingly powerful). If not mistaken engines are shimmed to cater a specific nitro content (around 25%)and relative altitude (which one IDK, sea level probably). What you want is to fit the most air/fuel in the combustion chamber without pre-detonation occurring by playing with nitro content, plug temperature and deck height.

I don't know much more than this sorry.

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Are there any tell tale signs of having too much or too little head clearance?

about to drop the restrictor size in my carb, what changes to the tune should i expect, will the engine run more rich or lean?