Air Nozzle and Motor getting very warm.

[leslieliang]

So I took off the upper to my AEG and decided to dry fire a bit with my finger lightly on the nozzle. I covered the nozzle with enough strength to not let air come out, but with enough leniency so that the nozzle could cycle back and forth. I noticed that the nozzle gets very warm as I was doing this. Does anyone know why this is happening?

Also, I decided to press down on the nozzle with a lot of force so that the nozzle can't cycle back and forth. The gears started whining from it. Does anyone know why this is happening?

Then I went out and shot a mid cap full of BBs and noticed that the motor, mag well, and the battery were getting warm. I think that the battery getting warm is normal, but what about that others? Why is this happening?

[DarkAngel]

Originally Posted by leslieliang

So I took off the upper to my AEG and decided to dry fire a bit with my finger lightly on the nozzle. I covered the nozzle with enough strength to not let air come out, but with enough leniency so that the nozzle could cycle back and forth. I noticed that the nozzle gets very warm as I was doing this. Does anyone know why this is happening?

No, Nothing touches the Nozzle. Nothing is connected to it xept for the tappet plate, but it does not cause friction, the only thing it rubs against is a brass tip of the cylinder head. Theres no reason why it should be warm, nor do I think its even possible.

Originally Posted by leslieliang

Also, I decided to press down on the nozzle with a lot of force so that the nozzle can't cycle back and forth. The gears started whining from it. Does anyone know why this is happening?

It shouldnt cause the gears to stop turning if you keep it pressed back. Its Spring loaded and keeping it pressed back just keeps it isolated from the gears, holding it out on the other hand will cause the tappet plate to snap or the gears to stop turning.

Originally Posted by leslieliang

Then I went out and shot a mid cap full of BBs and noticed that the motor, mag well, and the battery were getting warm. I think that the battery getting warm is normal, but what about that others? Why is this happening?

You have resistance with your motor or wires. This is caused by strain on the motor, or your wiring gauge being too small.

That being said, stop doing shit to your gun that its not designed to do.
If you're purposely trying to break it or break it due to stupidity, were not going to readily help you.

[MadMax]

There is a thermodynamic effect which heats air when you compress it. If you rapidly compress air such that it does not have time to bleed heat to it's surroundings (rapid cylinder compression) the compression cycle is nearly adiabatic (unable to transfer heat to surroundings). It's this effect which is why one might use an intercooler after a supercharger in a car to cool air before it goes into the cylinders. If you want to dig deeper:

http://en.wikipedia.org/wiki/Gas_compressor

http://en.wikipedia.org/wiki/Adiabatic_process


You do not want to fully block the gearbox nozzle and shoot full auto. If you restrict the escape of air too much, you can prevent the piston from moving fully forward for the next sector pickup. This can clash the sector teeth with the piston if they don't mesh properly. By blocking the nozzle, you also restrict the intake of air to the cylinder which makes the motor work harder because it's sucking against a partial vacuum. If you have a ported piston head this wouldn't happen, but if you have a stock one you'll be making the piston pull against vacuum.

It is normal for AEG motors to get warm while firing. However you should inspect your sector gear and piston for damage. If the teeth are gnarled, your sector won't mesh efficiently and your motor has to work harder.

[MadMax]

Originally Posted by DarkAngel

That being said, stop doing shit to your gun that its not designed to do.
If you're purposely trying to break it or break it due to stupidity, were not going to readily help you.

Dude, chill with the 'tude. The content of your post is pretty damn wrong and you missed some fairly obvious causes of potential damage in this guys mechbox and provided a heap of misinformation.

[DarkAngel]

That was not Attitude Carl that was a clear statement, but when someone posts "Im doing something to the gearbox that it isnt designed to do" and "this is happening", "Why does it do that?" Kinda makes you wonder...

That being said, Im not an engineer, nor do I pretend to be. I know alot more about Electronics than I do about the dynamic and thermal physics of air compression.

He would have to be SERIOUSLY firing the box on full auto with his finger on it, to make the nozzle heat up to become that warm. Especially since the air would pass through the brass tube and not the nozzle while he presses it against the base of the cylider head. (Meaning the brass tube would act as an inner liner, preventing the air from contacting the nozzle)

Im not going to post EVERY potential way he can break his box, hes putting the box under strains and conditions that its not designed to be in. Im not going to hit "all" of em.

I respect you enough not to get into a public debate about this, nor do I have the engineering knowhow to compete, but nothing I have said was Misinformation. I may not have hit "all" the possibilities, but thats far from Misinformation.

[leslieliang]

Originally Posted by MadMax

There is a thermodynamic effect which heats air when you compress it. If you rapidly compress air such that it does not have time to bleed heat to it's surroundings (rapid cylinder compression) the compression cycle is nearly adiabatic (unable to transfer heat to surroundings). It's this effect which is why one might use an intercooler after a supercharger in a car to cool air before it goes into the cylinders. If you want to dig deeper:

http://en.wikipedia.org/wiki/Gas_compressor

http://en.wikipedia.org/wiki/Adiabatic_process


You do not want to fully block the gearbox nozzle and shoot full auto. If you restrict the escape of air too much, you can prevent the piston from moving fully forward for the next sector pickup. This can clash the sector teeth with the piston if they don't mesh properly. By blocking the nozzle, you also restrict the intake of air to the cylinder which makes the motor work harder because it's sucking against a partial vacuum. If you have a ported piston head this wouldn't happen, but if you have a stock one you'll be making the piston pull against vacuum.

It is normal for AEG motors to get warm while firing. However you should inspect your sector gear and piston for damage. If the teeth are gnarled, your sector won't mesh efficiently and your motor has to work harder.

Oh. Thanks for your help! I believe it was heating up because I was firing on full auto with my finger on the nozzle and my cylinder is not ported. So that adiabatic effect should be the reason why my nozzle was getting warm.

Also, thanks for telling me that the piston might not be able to go all the way forward if I cover up the nozzle. I didn't know that could happen. I believe that was the reason my gearbox started whining because it only started whining after like 10 shots on full auto.

This is my first AEG and I don't know too much about the gun except what parts are where and their functions. The reason why I decided to cover the nozzle was because I was told that dry firing too much can cause the gearbox and other components to crack. So I thought trapping the air would cushion the impact of the piston on the cylinder head. But now I know that doing that can cause the piston to not go forward fully.

____________________________

@DarkAngel. Tell me something I don't know already. About 100% of what you posted I already knew.

Originally Posted by DarkAngel

No, Nothing touches the Nozzle. Nothing is connected to it xept for the tappet plate, but it does not cause friction, the only thing it rubs against is a brass tip of the cylinder head. Theres no reason why it should be warm, nor do I think its even possible.

This doesn't even answer my question. My question was "Does anyone know why this is happening?" My question was not "What is connected or comes in contact with the nozzle?" Nor was my question "Should the nozzle be warm?" You can actually learn from my post as you say "nor do I think its even possible" because obviously, from my experience, it CAN get warm.

Originally Posted by DarkAngel

It shouldnt cause the gears to stop turning if you keep it pressed back. Its Spring loaded and keeping it pressed back just keeps it isolated from the gears, holding it out on the other hand will cause the tappet plate to snap or the gears to stop turning.

Again, my question is "Does anyone know why this is happening?" My question was not "How do I break my tappet plate?" or "Will holding down my nozzle cause my gears to stop turning?" Everything posted above I already knew and did not help me.

Originally Posted by DarkAngel

You have resistance with your motor or wires. This is caused by strain on the motor, or your wiring gauge being too small.

This post actually answered the question asked, but only part of it. You answered the part about the motor, but not the magwell or the battery. I know my wire guage is really small as nothing bigger than 20 AWG can fit in the pistol grip, but shouldn't the wire be heating up, not the engine.
My battery is hooked to 14 AWG wire and deans. No idea why that's heating up.
The magwell shouldn't be heating up. I thought it was because of the nozzle, but this time, I was not holding down the nozzle like I previously was. The adiabatic effect should not occur now.

Originally Posted by DarkAngel

That being said, stop doing shit to your gun that its not designed to do.
If you're purposely trying to break it or break it due to stupidity, were not going to readily help you.

Then why do you try to help me? If you're going to have that crap attitude, don't help anyone. I'm trying to experiment with my gun because it's my first AEG. And why is it your concern whether I am trying to purposely break my gun or not. It's not your gun. It's my gun. I can get a new gun as easily as I can break my gun.

[Jackarutu]

And on a lighter note; now we know what type of question it takes to get Mad Max to come out of retirement and share his knowledge with us! lol

[m102404]

1. It's air compression creating heat...I suspect it's also friction. Feel the side of your cylinder after a bunch of shots...it'll be warm too. Even lubed up parts are going to create some heat as they move against each other.

2. I'm not sure what causes the grinding noise exactly..but it's coming from the gears being stressed. Carl (madmax) most likely described it best that you're plugging the compression area and the piston is hanging up.

3. Things get warm when electricity passes through them...heat is a byproduct because nothing is 100% efficient. That said...get to know your setup...and perk up when things are out of wack (i.e. things get HOT instead of the normal warm).
- different grips and motor plates will trap motor heat more/less than others
- not all motors are built the same...better ones dissipate heat better.

If you're just messing with things to figure them out for yourself...go for it. If you break it and need help, there'll always be people here to help and point you in the right direction.

*******not related**********
I've done exactly what the original poster described many, many times. Out of curiosity, out of interest, out of some feeble belief (read not based on any hard facts) that it'll help stop the front end of my mechbox from breaking off when testing things by cushioning the piston head from slamming full tilt into the cylinder head.

I've taken just a v2 mechbox...hooked up the grip/motor/big battery and held the trigger down until it blew up. Just for interests sake and to see what would happen. After 4000+ shots on full auto the plastic bushings cracked and the gears mangled themselves.

The very first tech question I asked on the forum was why a certain spring upgrade gave what seemed like such an odd boost in FPS...Skruface was nice enough to point out something very, very obvious.

No f*cking jumping down throats...no accusations of being an idiot.

Darkangel...don't know what your intent is, can't tell that via the Internet, but you come off as a f*cking asshole. You might have plenty of fans when you rage on newbies asking questions...but I'm certainly not one of them.

[Kos-Mos]

You might want to open you gearbox now.

Check the guides on mechbox.com about it...

The grinding noise is a very good sign that you broke something, especially since it started after about 10 shots.

If I had to take a guess, I would say bevel gear is broken or piston is stripped.
Most bevels are made of two pieces, and theses can be broken free of each other. The result is a grinding noise when firing... Piston is almost always stripped when you plug the nozzle, either with a BB jammed in the barrel or with your finger.

You really should change any part that you damaged. If it makes a noise, it is not normal and changing a 10$ part right now might prevent a 80$ part from breaking.

First time I opened a mechbox, I broke a tappet plate (It was a P90 an the tappet plate can be stuck on the bushing in certain conditions... I broke mine). It sucked but I learned a lot since then and now am offering gun doc to people in my area. Who knows, maybe you will discover a talent for theses things.

[Ninja_En_Short]

Just one thing : if you want to test the air seal, just take the air compression system (nozzle, cylinder, cylinder head and piston all assembled), put pressure on the nozzle (don't make the cylinder head go back into cylinder) and push on the piston, there should be some compression but you should be able to push completely (don't force it though).

[leslieliang]

Thanks for the advice guys. As of right now, I don't think anything has broken. My gun shoots the same as before I messed around with it. It's hard to tell. I don't want to check either because I have the CM Blowback Gearbox and those are hard as heck to disassemble.

The gears are not whining anymore. It only whines after ten or so shots when I hold the nozzle down. When I let go, everything is back to normal.

[DarkAngel]

@Op
I owe you an apology, Ive had less than 2 hours sleep over the last 4 days.
Im on a pretty short fuse atm and my head isnt 100% screwed on right now.

You didnt deserve that from me.

[MadMax]

Originally Posted by Jackarutu

And on a lighter note; now we know what type of question it takes to get Mad Max to come out of retirement and share his knowledge with us! lol

Usually I sit back on my heels and let experienced mechanics explain a fix. Kind of a habit developed from being halfway through writing a long post and hitting "submit" after someone else has reasonably addressed the post. I have trouble with brevity sometimes.

Occasionally a post pops up that asks a novel question and I rummage around in my brain and sometimes find just the right answer. So I crawl out from under a pile of aluminum chips and hit some keys.

Plugging the nozzle is a valid test of air sealing in your mechbox. You do have to make sure you're in semi mode and don't plug the opening when the piston is withdrawn though. If the piston flies forward and slams against the cylinder with the nozzle plugged, then you've got a fairly severe air leak either at the oring, piston head back (air can go through the centre hole and out the piston), or around the nozzle-cylinder head tube.

I also check air seal by plugging the barrel to see if the nozzle is registering in the hop up properly. Same thing, if the piston slams into the cyl' head then you've got an air leak somewhere down the chain. You can feel for a heavy poof of air out the magwell with a plugged barrel too. A little leakage there is normal, but if the hopup sleeve is damaged or out of place, you can get heavy air leaks out the mag well.