How do you find an Air leak??

[specter]

I need help quickly, I was running my GT today and I was revving it up pretty high and as it was coming back down it stalled and shut down. I tried to start it back up and it refused with some eratic firing noises it sounded like the timing was off but this is impossible right?? anyways I proceeded to take off the heatsink to make sure the sleeve was alligned turns out that it was I put it all back together and checked that air came out the exhaust when I turned the starter (very little) I covered the carburateor and there was no suction this leads me to believe that there is an air leak somewhere. please help.
thanx

 

[El Pirata]

Real quick, the fuel lines are connected? I know that's a rather silly question but how many times have we predicted the worst and overlooked the simple. If it's not that then check you fuel and return lines by taking them off and slowly stretching them looking at them from one end to the other for signs of a tear. If no tear is present then it could be your connections where your lines plug into. It you are not using a fuel line clamp then you can use a zip tie or make one out of extra fuel line.

 

[specter]

fast response thanx, I'll check but it sounds like the leak is somewhere under the heatsink I blew on the exhaust (burnt nitro is disgusting) and it sounds like air is coming from under the heatsink so I retightened it and it still won't start. this is horrible I'm going to have to bring it to the hobby shop or something.

 

[El Pirata]

Did you by chance crack your engine wide open.

 

[robriguez]

The heatsink I though just sits on top of the head surrounding the glow plug. The only place I can think of for air to escape is through the hole for the glow plug. Have you checked your glow plug? Have you tried replacing it?

If it aint the glow plug and you still think theres air comming out Pirata might be right...you may have cracked your head.

 

[joneser4u]

good luck, I've got a T-MAXX with a pro.15 that I've been chasing a air leak for along time???:help:

 

[RobH]

how about where the exhause header meets the engine? there is a gasket that keep air from leaking out. a hole in the gasket would ke it sounds like air coming out under the head. it could be what el said (hole in the crankcase). They best thing you can do I think is take the engine all the way out and inspect it. If needed, maybe take it apart.

good luck,
Rob

 

[SilentHunterKellen]

edit

 

[El Pirata]

Dead link.

 

[maxxtrac]

try taking a squirt bottle full of water and spray the suspect areas. if the engine dies you know you have an air leak. This is the method i have used and it works very well

 

[SilentHunterKellen]

umm
be careful of water near metal. Water has a tendancy to make things rust. Just make sure you clean up the mess you make quickly.

 

[specter]

EP got it right, there is a 11.4 mm by 6.6mm hole in the bottom of my engine. I emailed associated about it to see if they might replace it but I am not sure of this.

 

[robriguez]

11mm=approx 7/16inch!!!!!! HOLY CRAP!!!!

 

[specter]

Its pretty big, do you think that AE will replace it because of a fault in the machining because I have never seen or heard of a crack that big.

 

[robriguez]

I'm still new to Nitro engines myself but if it were a Real engine i would say that the only way you can get a HOLE is if something on the inside broke and came flying through the block.

Have you taken the engine apart further? Is the conrod or the piston still intact?

Usually most manufacturers will make you send it back to them so they can inspect the damage. If they determine that it was due to running the enigne TOO lean or at too high RPM they will probably NOT replace it.

 

[specter]

Here is a picture of the hole.

 

[robriguez]

If you take the glowplug out and turn the flywheel...do you see the piston moving up and down.....if not, I think you broke your conrod or a peice of your piston sleeve and it then broke through your engine block....

 

[GilBeQuick]

Holy crap.... that's the graddaddy of all air leaks!! hahaha and you had trouble finding that little pearl hahaha. dang man, why don't you try JB Weld-ing that thing LOL

 

[specter]

the piston still moves up and down when you turn the fly wheel, I think that the con rod is broken and the piston was on the ignition stroke and it forced the conrod through the bottom of the engine. It still functions normal but there is some difficulty turning the flywheel when the rod is near the hole.

 

[SilentHunterKellen]

It fucntions normal with that huge mouse hole in it? Damn man how did you not find that. I think its time for a new engine or a new crankcase at the least!