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hows my piston look?

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ausher

ausher

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I probably broke this motor in the worst possible conditions. 20-30°f, but I took every measurement to do it correctly with best results. It has 1/2 gallon through it. I started it inside with a sock on the head. Warmed it up to 200°f outside. Did the heat cycle break in method. Took it inside quickly after its shut off with piston at bdc.
It runs and idles excellent. I can let it idle for ever and punch the throttle and the power is right there. Hit the brakes and it returns to idle without even thinking of dying.
Anyways.... lrp z.28s3
2013-01-06_00-12-20_770.webp

2013-01-06_00-12-42_307.webp
 
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Perfect! Almost like there hasn't been any fuel through it yet, which makes me wonder how many tanks you've been through yet on your 'break-in'? I would suggest you need to get at least a gallon on that thing before it's truly broken in and you can start laying into it.

I would get back out there and keep running it. Don't worry about shutting it off between tanks etc. Just keep re-fueling while it's running, keep temps up(NOT by leaning it out, but by using the sock etc), and go easy on it tank after tank. The last engine I broke in I went through an entire gallon and only started the engine twice. No need really to turn it off between tanks.
 
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Thats a matter of opinion rather than fact. While I will agree that close to a gallon before truly beating the hell out of the engine is a good idea most here would disagree with only shutting it down a couple times during the breakin period. The heatcycle method is probably the best method for breakin IMO as it allows all the parts to properly wear into each other vs keeping them hot for a full gallon will not allow the cycle to happen. Again its a matter of opinion but most will tell you to cycle it.

Ausher - The piston looks great for a 1/2 gallon of fuel
 
Did you wipe the button and piston clean before the pic? There should be a nice honey lookin sheen all over everything.

My newest picco was started 4 times total the first gallon. That's almost no stress on the internals compared to the heat cycle method. Start, stop, cool down, preheat, start, stop......... And so on. You can clearly see how stress is involved with heat cycle. I agree that heat cycle sucks But break in methods are a matter of opinion and everyone does it differently.
 
Yeah there are many opinions on the subject. If you think about what's taking place throughout the process it's easy to see how heat cycles can be tough on things.
 
DreamMachine said:
..... That's almost no stress on the internals compared to the heat cycle method. Start, stop, cool down, preheat, start, stop......... And so on. You can clearly see how stress is involved with heat cycle. I agree that heat cycle sucks But break in methods are a matter of opinion and everyone does it differently.
Click to expand...

2revo1maxx said:
Yeah there are many opinions on the subject. If you think about what's taking place throughout the process it's easy to see how heat cycles can be tough on things.
Click to expand...

+1. You got it, that was my exact point.



Phins Fan said:
Thats a matter of opinion rather than fact. While I will agree that close to a gallon before truly beating the hell out of the engine is a good idea most here would disagree with only shutting it down a couple times during the breakin period. The heatcycle method is probably the best method for breakin IMO as it allows all the parts to properly wear into each other vs keeping them hot for a full gallon will not allow the cycle to happen. Again its a matter of opinion but most will tell you to cycle it.

Ausher - The piston looks great for a 1/2 gallon of fuel
Click to expand...



But aside from which break-in we all think he should do.... I do believe that we would all have the same opinion that he's hardly got enough fuel through it to be leaning it out and giving it a performance tune. BUT - that's where the 'fact' comes into play, and not the opinion. The 'fact' is, that if it's still got a ton of mechanical pinch left, it needs more fuel through it before it's broken in.
 
I've got an OS 18 that has seen upwards of 2.5 gallons thru it and still needs to have the glowplug loosened from time to time because it has too much compression to turn over a full cycle. Would it be "fact" that my OS isnt broken in yet either? I've had a solid race type tune on this engine for the better part of 1.5 gallons.
 
That's compression. Compression and pinch are two different things. I mean no disrespect by the way. :) I'm only saying that you're better off waiting until the pinch is relieved before running the piss out of an engine.
 
Thanks for the info. I did wipe the oil off the piston and button. I'm waiting to actually tune it when I got a gallon through it and when.its warmer. Until then I'm keeping it rich as I can.

It still has that.mechanical pinch and I sometimes loosen the plug to start it. It runs and idles great. Starts right up 90% of the time. Sometimes it gets loaded up with too much fuel.
 
It looks perfect, since you said you wiped it. At first I thought you might have been running a little lean.

Here's a 2.5 I was running a few years ago. Perfect tune about 2 gallons in.

IM000200a.webp
 
If it is blackish colored. It means running running rich. What.color if too lean?

Also I checked my fuel. Look like I have almost a gallon through it. Gallon jug has about 1/8 left....
 
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Heres my motor Picco 28, with a little more than 3/4 gallon thru it, running Werks 30% and McCoy 59 plug.

The motor should have a nice honey lookin sheen to it unwiped

602_zps9097b918.webp

603_zpsf792c8e9.webp


This here is the chrome ring made from the pinch. Now the idea is the ring should be shinny and constant, but not every motor will do this esp cheaper motors. When it is nice and smooth it means its a perfect seal. This particular motor is not fully broke in, so this is what partial seal looks like.

604_zpsfc66dc8f.webp
 
The color is from the fuel. At the time I was running Blue Thunder and Top Fuel.
The pic with the popped piston is absolutely bone dry.
 
This is my 5th nitro engine I ever owned and I ran more fuel through this one than the other 4. DreamMachine that's how it looked before I wiped it all off.

So..... if there is a big hole in the piston.... its too lean:whhooo:
 
lesclaypool said:
That's compression. Compression and pinch are two different things. I mean no disrespect by the way. :) I'm only saying that you're better off waiting until the pinch is relieved before running the piss out of an engine.
Click to expand...

It's most likely from over-priming the engine. I've had 5 gallon engines that wouldn't turn over if they were slightly flooded.

You don't have to wait for the mechanical pinch to be gone before running an engine hard, because it goes away as the engine warms up. I usually go about half a gallon before race tuning any engine with the exception of a Picco. Once the parts have been broken in there's no need to worry about pinch, just make sure it's warmed up and tuned before running the piss out of it.
 
It looks better than the top of the piston in my trx .15 pro. and that has probably 2-2.5gals through it. But it still runs good so I'm not worried. Probably ran it lean when I didn't know much about nitro engines. It is a learning experience after all.
 

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