How to check if piston sleave has been damaged

[coldvod]

I flipped my truck and it fell in some mud. I then proceeded to clean the cooling head best i could but i can't take it off since some of it got the 4 screws that hold it down and the idiot that i am i took off the glow plug.now it feels gritty when i turn it over. Its a big red .28 so a piston sleeve is only 80$CAD while a new .21 is 90$ more.

To get to the real point. How do i check for piston sleeve damage? Will the scratches of the mud/dirt be visible to the eye or will i just have to feel it by moving the piston in it.

 

[gandalfnz]

I would not try to move the piston if you think you got mud/sand in there.
In order to inspect for damage, you would need to remove piston and sleeve and have a visual check, you can also check for pinch at the same time.
When removed try to push the piston up the sleeve by hand and see how far it goes, if it reaches the top or goes past, its time to replace the piston, sleeve and conrod.
Hope that helps.

 

[Chubaka]

I had that happen to two motors. The first I cut the cooling head as I had spares. This one I'm debating. Both were Traxxas Trx pro .15.

First thing first, blow the motor off befor looking any farther.

You can look in the exhaust port at the piston. Me personally, I would use a q-tip in the glow plug hole to see how dirty it is. If its just gritty, maybe wd40 or 3 in 1 in the glow plug hole and piston bottom dead center. Open the back plate and collect oil. Hopefully it will flush all contsminants out.

If the motor shuts off when warming up, thats a good sign the dirt has won.

 

[tntpoof]

so flushing motor some way will not help. Id say pull motor apart clean thoroughly

 

[cbaker65]

Be aware that some pistons can not be at bottom dead to take the backplate off ,
not sure about that engine ,but on some ,the piston will go down in a groove that
is in the backplate on bottom dead ,you will stand to damage the piston if that is
the case ,always set the piston up a little in the sleeve!

 

[coldvod]

I've gotten around to take it off. I dont think its dammaged but i would mind a second opinion

Taken the sleeve out. doesn't look dammaged

 

[gandalfnz]

With the sleeve out, remove the piston as well, and try to push the piston up the cylinder by hand.
Can the piston reach all the way to the very top and even start exiting from the other side of the sleeve?

That piston looks quite good, either ran it rich or barely used, not even any deposits on it, unless you cleaned it.

Cheers

 

[coldvod]

With the sleeve out, remove the piston as well, and try to push the piston up the cylinder by hand.
Can the piston reach all the way to the very top and even start exiting from the other side of the sleeve?

That piston looks quite good, either ran it rich or barely used, not even any deposits on it, unless you cleaned it.

Cheers

When i took it out i washed it. I ran it rich yes theres also still decent pinch
Maybe not as good as i thouhht

 

[gandalfnz]

When i took it out i washed it. I ran it rich yes theres also still decent pinch
Maybe not as good as i thouhht

That is good enough.
Unless the sleeve/piston is scored/scratched this one is good, should work no problem.
Just give it a good clean, put back together and off ya go.

 

[coldvod]

That is good enough.
Unless the sleeve/piston is scored/scratched this one is good, should work no problem.

Thanks i will do a complete teardown anyway to check bearings because my season is over

 

[cbaker65]

A piston & sleeve can be damaged with out any scaring!

 

[olds97_lss]

When i took it out i washed it. I ran it rich yes theres also still decent pinch
Maybe not as good as i thouhht

If you can push it that high with very little force... it's likely about worn out.

This is one that was damaged beyond usefulness:

One of the engines ball bearings in the rear bearing actually split in half and went through the engine:

Made a mess out of the crank case too.

And a couple that were pretty worn out:

These were after being repinched by RayARacing. Not sure if he still does this service or not, but it was $25 each to repinch... back in 2008. lol!

 

[cbaker65]

You can damage it by not alowing it to be heat soaked first!
No physical signs does not mean that there is NO damage at all to a nitro engine!

 

[gandalfnz]

You can damage it by not alowing it to be heat soaked first!
No physical signs does not mean that there is NO damage at all to a nitro engine!

Basic checks and the most of us do are visual for damage, and pinch.
Any other as far as I know would be very hard to tell, and would not be as important.

 

[coldvod]

Just as an update. My engine runs perfectly fine thankfully no need to replace any part on it just yet *knock on wood

 

[Kevinb]

Great, I was going to chime in and say, clean it, assemble it. Run it.