Opened the back of my OS .12TZ(P) 3-Port for the first time today...
 

I finally got around to removing the cover plate of my engine today (first time), after runinng about 3/4 of a gallon of 20% Nitro through it (break-in + 5 race days). Given all the stories I was hearing about how much "gunk" people were finding in their engines after just break-in alone, I was kind of worried about what I might find. Other than some discoloration on the crankshaft and on the connecting rod around the crank wrist pin (Yeah, I Know what you're thinking! :lol: ), I didn't find that much gunk in it.

Attached are two photos. On the crankcase, the oil discoloration is just a reflection.

Any comments or advice?

Thanks! :)

BTW: I have to go find myself a flywheel removal tool before I can pull out the crankshaft. :rolleyes: :lol:

Are you running it with water???

No. I'm not sure if you are joking around or not...

gunk
 

are you using any type of after run ? the pic. of the crankpin and counter weight are really rusty. thats not good ! it will kill your motor faster! :eek:

What fuel have you been using?

I don't think that's rust. It looks like some discoloration from the fuel. I think it looks fine. Is the counterweight smooth and oily or rough and gritty?

Answers to questions:

isuzuguy: Yes, I am using after run oil, 10 drops at least.
munrath: 20% Nitro as stated above
jag: Smooth and oily, but discolored as shown. It's blotchy.

Try to use different brand of fuel-switch to O'Donnell and will never see it again.
What you see inside your engine-is not normal. If you can easy remove it with just a piece fo fabric-that it is "garbage" in fuel if you have to use very fine sand paper-most likely it is water damage. In any case it will make life of your engine way shorter.
I have REX (practice motor for my son's RRR) with about 8 gallons of O'Donnell through it, never use after run oil and didn't open motor since last year, Month ago finaly open it to see if engine still usefull for car tunning practice and as usualy it is perfectly clean and shiny.
Edward

Thanks Edward. I've been using Mugen Seiki 20% Nitro.

Stick with the mugen fuel! Its very high quality. Aka byrons fuel.

Because of our humidity, you should use the afterrun to sort of flush the nitro out of the motor. Put a few drops in the carb and plug area and spin the motor. Then do it again. And maybe again. If you're willing to disassemble the motor after each race and clean and lube it, that would be better. I've seen cranks rust in one day after not using afterrun. Lucky you live Hawaii. Just look at our stadium.

Yup! The humidiy and that fresh pacific ocean salt air blowing in from across the street! The salt air didn't quite dawn on me until I was posting something in the Murnan Modified threat. :lol: I still remember when I drove black cars and went to the beach, the salt would just be sitting on the car.

I was hoping to avoid having to take it apart after every race. :( I know some guys do, but I think it just increases the chances of introducing an air leak. :nod:

Maybe I'll get lucky and it won't be rust. That's a tough spot for the engine to burn off any gunk. Wishful thinking! :lol:

now that your close to the topic of rust and after run oil, is it necesary to use a rust inhibitor when you are using after run oil.

Most modern after-run oils (Hobbico, etc.) have rust inhibitors and other anti-rust agents mixed in with the oil.