boosted

hello, i have an OS 15 CV-X engine which is giving me problems.

when i try to start the engine i get a knocking sound from the piston. i replaced the piston and sleeve only for it to still happend.

what could be wrong, what should i do?

- dave
[email protected]

proptop

My Feedback: (8)

Welcome to RCU...Well, first off, it's really hard to tell w/o actually hearing and feeling what's going on. If you have a worn connecting rod and piston pin (wrist pin) you will not have cured your problem by changing the piston/ sleeve. How much running time is on the engine? What does it sound and feel like when it's hot? Does it get worse?

boosted

thanks proptop, good to be here.

well it makes the sound when i pull on the starter. its kind of like a clicking metal sound when the piston gets to the top. it wont start and i cant figure out what else to look for. after looking at the rod and pin they both looked fine, no real visible signs of wear. the engine doesnt even have a gallon thru it. i also noticed after changing the piston that the original piston still looked pretty good and from what i've came to understand still had compression cause the piston didnt go completely thru the sleeve.

when i pull on the starter i also feel a clicking sound. i switched the starter with a backup i had and it still kept doing it.

i'm stumped and burnt out, any other help would be greatly appreciated.

CaNaDiAnRaCeR

What kind of glowplug are you using? Maby your using a long plug when your not supposed to so your hearing the piston hit the glowplug. I never heard this happen before cause I use long plugs in my standard plug engine all the time but that is all I can think of.

boosted

well basically i'm using the same glow plug i was using before the engine blew. checked it out and everything seemed ok so i left it in.

this really sucks, worst part of it all is i might have spent $50 on a brand new piston that might not even be the problem now.

thanks for the help, please keep the suggestions coming!

CaNaDiAnRaCeR

It has to be a fairly simple solution since R/C engines basically have only 3 internally moving parts. Does it make the "knocking" noise EVERY time the piston turns over?

boosted

it make the sound everytime the piston hits the top. without the glow plug in it doesnt make the sound which seems to me like if the piston was hitting the glow plug but the only way that would happend is if there was no compression in the sleeve. that cant be cause i just bought a brand new piston and sleeve, what gives?

Harvester of Sorrow

does the engine still have shims between the cylendar head and the top of the sleeve

boosted

yep, brand new one i replaced while rebuilding the piston.

do any of you guys think it could be something wrong with the pull start, clutch, or crankcase that would make this kind of sound? now i've lost 2 engines to the same problem and have no idea what it is. to top it all off i cant find anything on the web related to it either.

CaNaDiAnRaCeR

Hey, guess what. I was telling my friend about your problem and he had the exact same problem with his brand new .12 CV-R. He thought something was seriously wrong and took it into our LHS and the guy said that on new engines (especially with O.S), the connecting rod squeaks on the side of the engine block when the crank is coming up to TDC. He says it will do that till the engine is fully broken in. Its nothing to worry about

boosted

thanks for all the help guys i actually found out what the problem was yesterday. it actually turned out being that the pilot shaft was loose and that what was causing the noise and not letting the engine start. now i'm stuck with a new piston and sleeve but atleast t he cars running. thanks again.