Engine Scraping noises

[miller94]

when i turn over the crank by hand, it makes a scraping noise/feeling. almost like its coming from the piston. i checked the wall and piston head and everything looks fine. anyone have any ideas what would be causing this, or if its normal?

 

[cwal1774]

Could be a crankshaft bearing.

 

[miller94]

ok, so if i decided to start the truck, would it cause much damage or would it be ok?

 

[miller94]

or could it just be the ring around the piston causing the noise? the noise to me seems like metal on metal, but not very loud and barely noticeable.

 

[NCNitro]

nitro r/c engines don't have rings.

 

[miller94]

dude yes they do, it shows it in the manual when it shows how to take the piston out.

 

[2revo1maxx]

DUDE, No they don't!

What you're feeling is most likely the engine's "pinch" or tight spot. Nitro engines have a tapered sleeve that is tight at the top. As they warm up and break in the chrome plated brass sleeve will expand a little more than the aluminum piston. This frees the engine up and explains why they run rich when cold and run nicely when warmed up......assuming you have it properly tuned.

 

[MudSlinger33]

^^^Ha Ha, Nope no rings. What you may be seeing in the manual is the brass shim that goes between the head and the block, could be mistaken for a piston ring.

 

[flipskatter6]

No piston rings...no nitro mOtor has rings. The pairing are sleeved because the temperatures get to high for normal rings

 

[TRXaddict]

Is this a bran new or it has been broken in and driven around?

when did this suddenly occur ? If the engine has been driven for awhile it actually could be a bearing if your sleeve is smooth and no scratches or anything I'm guessing its something with the crank shaft. Might be a small small rock that made it somehow through your filter or some sort of debris that got in there that might be wedged in. I would NOT start it while it is making a noise like that. But most importantly is that you can feel it scrapping so there is something rubbing or possible digging into somewhere.

It may be alot but i would just take the motor out and completely disassemble it and check EVERYTHING. The bearings how smooth they spin, the crank shaft, rod, piston sleeve just because you dont wanna chance it having something rubbing or foreign object in there causing more and more damage every time you crank it over or even start it.

Good luck and keep us posted what it was.

 

[NCNitro]

dude yes they do, it shows it in the manual when it shows how to take the piston out.

Dude, how long you been running rcs? I have over ten years experience with nitro, and NO, they do NOT have rings!

 

[TRXaddict]

Dude, how long you been running rcs? I have over ten years experience with nitro, and NO, they do NOT have rings!

Maybe hes mistaking the head gasket ring for a piston ring ?

 

[frickenjoey]

dude yes they do, it shows it in the manual when it shows how to take the piston out.

Ground based RC do not have piston rings...period. It is not the temp that restricts this but the RPM. Any engine that turns much over 15K with destory them which is why a ground based engine uses the tapered sleeve to build compression. Some airplane engines have piston rings...but if you think your T-maxx does you are obviously reading the wrong manual or not comprehending what you read. They do have oil lines/grooves cut around the piston for lubrication purposes however rings they are not.

Back on topic....If I was you I would pull the engine and break it down and check EVERYTHING. Check bearings, mating surfaces and flush out the case real well. If you run it and there IS something in there your engine is shot.

 

[2revo1maxx]

I still think it's pinch, or a burned up engine.

 

[TRXaddict]

Ground based RC do not have piston rings...period. It is not the temp that restricts this but the RPM. Any engine that turns much over 15K with destory them which is why a ground based engine uses the tapered sleeve to build compression. Some airplane engines have piston rings...but if you think your T-maxx does you are obviously reading the wrong manual or not comprehending what you read. They do have oil lines/grooves cut around the piston for lubrication purposes however rings they are not.

Back on topic....If I was you I would pull the engine and break it down and check EVERYTHING. Check bearings, mating surfaces and flush out the case real well. If you run it and there IS something in there your engine is shot.

+1

I think hes mistaken the head gasket washer for a piston ring.. I'm sure in a break down photo it will show the head then under that the HG then the piston. Maybe he things that is for the piston or something.

 

[2revo1maxx]

You said that already, and it's also been said in post #8.

 

[TRXaddict]

I know i just thought no one saw it lol i know sometimes people will just press post reply from the top and then you dont see the above so i decided to say it to the next person that was talking about no rings. just tried to maybe see what someone would agree if that would be the case ? I'm just trying to figure out what would make him see or read about a ring in there.

 

[frickenjoey]

Who knows....people will argue the stupidest crap because "The guy at my Local Hobby Shop said so". Yeah ok slappy....Just because they work there does not mean they know thier stuff...my dad was also in the Navy but that does not mean I know poop about boats. All good let him believe what he wants.....oh yeah Santa is real too. Sigh....

 

[2revo1maxx]

What? No santa?:whhooo:

 

[frickenjoey]

Yeah I know what a shock right? Sorry to break it to you like that...