maxboost

i was running my rc today. one time, at full throttle, i heard a loud bang like a firecracker coming from the engine. it still runs but it makes this grinding sound. what is this grinding sound? it only makes that sound when i let off the throttle, and it slows the car down. i need ur help!

ChrisO

pull the whole engine apart, you probably broke something but not fully

Im2lazy

Could be a clutch bearing or part of the clutch me tinks, so look well in that region.

That's what I think.


This reminds of the day that I was racing and my racing buddy was trying to bench tune his engine.
And so, he revving his engine, it started to revup with that sweet sound that only a nitro engine posseses, then !POP!
I thought a Harley's engine had backfired, but when I looked behind me, My friends super nitro belted tires EXPLODED! . A shred of the insert finally hit the ground feet from him and his cigarette was no longer between his lips, but on his car. And the car was still idling.


i have a feeling that this didn't happen to your car . One would hope you would've noticed.

I couldn't help but laughing because I had never seen anything like it happen ever before, and I doubt I will here about anyone else having this problem. i hope .

maxboost

i think i figured out the problem. today, i had a hard time starting the engine, theres too much resistance on the pullstarter that i cant even pull it all the way. after a rough try, boom! there goes that boom again and lots of oils squirted out from the exhaust. i think i have a clogged exhaust? maybe i drawned my engine?

Im2lazy

No, you flooded your engine, and that means you had too much fuel in the engines combustion chamber. when this happens, stop pulling and remove the gow plug and turn the car over so that the extra fuel in the combustion chamber flows out. Since your fuel does not compress the way air does, the piston will have a lot of force exerted on it and since it is so storng, the force will then travel to the conrod, and could lead to a broken conrod; bad .

However, this is not your weird noise problem. You really should investigate it more closely soon, otherwise that one part that is making that girinding noise farts out and messes something else up.

maxboost

i think i know where the grinding sounds coming from, yesterday my engine mount bold got loose and my engine is shaking roughly. the spur is a little stripped but not all teeth only like 5. i think thats where the grinding sound is coming from.

Im2lazy

if your spur gear gets stripped, then your clutch bell won't even be able to engage the spur gear. Your spur gear just got eaten.

I still don't think that it is that, that should sound like a bad shopping cart wheel, you know, those rusted ones that only spin every once ina while. If you were concerned about a constant grinding sound then this is not it.

Replace the spur gear, use locktite on your engine mount screws and see if you still have the problem.

sausage_link

lol i stripped my spur gear as well but my car stopped
i didnt strip it to much coz i relised wat i was doing so its not that bad