Newb Here...

[Paul]

So I've had this 1/8th nitro sitting assembled for some time and finally got around to starting the break-in process for my Dynamite Mach 2 .21 engine using the heat cycle method. Had the engine running pretty good. Even ran some figure 8's in the street for aminute. Not fast mind you...but not super slow. Anyways, now when I attempt to start the engine it will only start if the carb slide is opened a bit and will not hold an idle, have to use throttle to keep it running. At this point I've reset to factory setting and still have the same issues. Carb gap is very close to 1mm and always has been. So in my mind, understanding how a carb works (fuel air mixer) I'm thinking I'm running rich and may need to increase the carb gap a touch. I did also notice upon blipping the throttle some fuel was spitting out of the exhaust. So I need to lean it out and really my only question is whether to start with the LSN or HSN? In so far as achieving a solid idle. I've done A LOT of reading, found the flow chart, thinking maybe some of you have experience with these engines and maybe can point me right to some good setting for break-in. The factory setting aren't working. Could be the carb slide gap but everything I've read states 1mm for just about every engine. Thoughts? Appreciate any help.

Also. I'm gonna take the engine apart tonight and clean it good with some carb cleaner, oil it up and seal everything with some
RTV. No leaks but something that
needs to be done.

 

[hotrodrob]

hold off on ripping it apart just yet,sounds like it runs just right for a new engine,lean the lsn a 1/16 and continue the heat cycle,your temps need to be upwards of 220f,..do you have a temp gun?

 

[Paul]

hold off on ripping it apart just yet,sounds like it runs just right for a new engine,lean the lsn a 1/16 and continue the heat cycle,your temps need to be upwards of 220f,..do you have a temp gun?

No temp gun. Getting one tomorrow. Already have the engine apart. No worries there. I'll have it cleaned and put back together in a jiffy. Slight speckling on top of piston. Normal wear on clutch plates (things) and the housing. Only thing I'm not sure about is the ported section of the crankshaft. It's a bronze/brown color. Is that normal?

 

[Rolex]

The coloring is usually a signature of the fuel you use.
Nothing wrong with sealing it now that it's apart. If it's cold where you are, you'll need to cover the head with a baby sock or tin foil to help keep the temps up. Factory settings are only for the first part of the break in, and need to be adjusted as you go. Hotrodbob is right regarding the leaning of the needles and the temp.
Take your time, do it right.

 

[hotrodrob]

i concur,..best thing is lets take it one step at a time....use the ultra copper rtv,afterward get back to us,....when sealing the backplate use a thin even layer,assemble finger tight,then tighten the next day,this imo produces the best possible seal

 

[Paul]

The coloring is usually a signature of the fuel you use.
Nothing wrong with sealing it now that it's apart. If it's cold where you are, you'll need to cover the head with a baby sock or tin foil to help keep the temps up. Factory settings are only for the first part of the break in, and need to be adjusted as you go. Hotrodbob is right regarding the leaning of the needles and the temp.
Take your time, do it right.

Here's a pic of the port end of the crankshaft.

Here's a pic of the port end of the crankshaft.

Feeling like I'm having to use to much force to remove the front crankshaft bearing from the crank case. That normal? Don't want to break it trying to push it out. Will carb cleaner hurt the bearing if left in?

 

[hotrodrob]

if it aint broke dont fix it!.....looks fine,what is it your looking for?......stop picking dude.....

 

[Paul]

i concur,..best thing is lets take it one step at a time....use the ultra copper rtv,afterward get back to us,....when sealing the backplate use a thin even layer,assemble finger tight,then tighten the next day,this imo produces the best possible seal

I have high temp red versa-chem RTV. Rated to 650F. That should work right?

if it aint broke dont fix it!.....looks fine,what is it your looking for?......stop picking dude.....

I didn't think it was broke just wanted to seal the engine and check out the internals more out of curiosity than anything. Suggesting not to clean before sealing it up? Might agree if I can't get the bearings out.

 

[hotrodrob]

if its rated @650f then more than good on that.
leave the bearings be,never screw with them unless they need to be screwed with..
best make sure all is clean now since its all apart,one piece of sand or a chip off a pic is all it takes to screw up a bearing,
make sure the p/s is in the right way and give a drop of oil on the bearing after being cleaned

 

[Greywolf74]

the crankshaft bearings are pressure fit so you have to heat the engine up to about 225F and then either tap the case so the bearing drops out or use a wooden dowel rod of some kind to push the bearing out. You'll have to do the reserve to install them. Theres no reason to take them out though unless you need/want to replace them.

 

[Paul]

the crankshaft bearings are pressure fit so you have to heat the engine up to about 225F and then either tap the case so the bearing drops out or use a wooden dowel rod of some kind to push the bearing out. You'll have to do the reserve to install them. Theres no reason to take them out though unless you need/want to replace them.

Yep left the bearings alone. Lubed up sealed up and put back together. Noticed that the head of my glowplug is well blackened. Still working though. Now to get this thing to run lean and mean. Have to wait till tomorrow though, SUPER cold today.

 

[Rolex]

These things don't like to run in the cold.

 

[Paul]

Ok so I've got her idling again. Whats the consensus on idle speed? High idle without engaging the clutch or lower idle speed? Right now my idle speed is pretty high. Not enough to engage the wheels but just barely under that speed. I went for a full throttle run to start heat cycling and full throttle killed the engine. At this point of course the battery in my glow igniter was to low to start it up again. Pretty sure I need to richen the HSN a turn to fix full throttle cut out. Oh and something I've noticed, even before taking the engine apart, vapor bubbles back out of the HSN into the fuel line sometimes after the engine gets hot. This cause by the carb getting to hot? Thanks for the help peeps.

These things don't like to run in the cold.

I warm the engine up before trying to start it. But your right for sure. Once I get these final adjustments made I'm gonna take it to the local indoor track and see how she does.

 

[Paul]

Running like a dream now! Idle issues boiled down to the linkage arm clamp on the servo horn being too tight causing my idle to be erratic among other things. Got some more break in time in today. Even got a little video.

 

[TRAT]

Break in is the most crucial part of any new/engine. So normally in real cars high rpms and break in oil. Kinda the same with any RC motor. Good fuel for RC let the rpms run high as the piston and rings are getting set with the block. Once broke in. It will be just fine. Just keep a eye on temperature.