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Modified break-in procedure and question on temps at each stage.

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Old 08-14-2014, 10:18 AM
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ijpom
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Default Modified break-in procedure and question on temps at each stage.

Hi all,

I'm more than a decade out of RC, and was a young teen when I touched a nitro engine last. I've never broken in or tuned a nitro. Call me a noob.

Just got a Hurricane XTR with the SH 28 engine and I am attempting to follow a break-in procedure. My readings initially guided me toward the traditional 5 tank method, starting with idling for two tanks and then figure 8's at 1/4 throttle for two tanks. My car started with great difficulty and spat copious quantities of raw gas out of the pipe (it's expected it to be rich, right). The car would not idle/run without the igniter attached. The heat sink was never hot to the touch.

Further reading talked of the heat cycling method of break-in, and about the factory position of the carb screws and needles. As I didn't see the engine breaking-in and getting better running on the stock settings, I decided to start from scratch with my carb settings. The result was that both the stock settings (as delivered to me) were between 4 and 5 turns out on the HSN/LSN. I corrected these to 3 an 3 and made sure the carb opening was at about 1mm for idle.

With tank 5 (after carb adjustments) the car started and idled well, I could take the igniter off and I was able to run with some speed. I did the 2 min run/10 min cool down, 4 times on the tank. The heat sink got hot each time and I could not touch it. There was lots of smoke from the exhaust at mid to high throttle but nothing at idle. The raw fuel had stopped coming out of the exhaust.

The next tank (6th) will be like the 5th, doing the heat cycling. I now have a IR thermometer to point at the plug and read temps, and ensure I don't get above 230F and have no smoke from the exhaust.

As far as I can tell the first 4 tanks were wasted time and fuel instead of doing any break-in. Does anyone have any experience with this "modified" break-in, or the temps that are expected for each of the break-in steps? I'm told that temperatures are critical for a good break-in (don't over heat). If I see 230F while running with lots of exhaust smoke, can I lean down the HSN some more? Is there a don't go over temperature?

Thanks for reading

PS - any recommended offroad tracks in the Western Suburbs of Chicago would be helpful. Joliet and Valpo,In are the closest I can find.
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Old 08-15-2014, 08:37 AM
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Redcat James
 
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As long as you keep it under 250 degrees you should be fine.
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Old 08-19-2014, 07:56 AM
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Hi James,

Thanks for your input.

The car is running well and blowing lots of smoke, so that tells me all is OK.
My new IR thermometer is cheap, and gives readings up to 310F after a quick blast. I don't know if it's designed for this purpose.
It looks like http://www.ebay.com/itm/281406164033...%3AMEBIDX%3AIT

Is there a recommended unit which can measure glow plug temp more accurately? What you you use to get your temps at 250F or less?

Thanks
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Old 08-19-2014, 08:33 AM
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That should work just fine.
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