reelquick

OK, clunk and vent from tank.
Nipple on muffler, carb and why is there one on the back of crank case ? Is there a tee?
Just wanna hear it run.
First 4 stroke.
Thanks.

600Bob

Nipple on muffler connects to the tank vent to pressurize the tank.  Clunk line to carb. to supply fuel to engine.  Crankcase has a vent to open air, good idea to but a filter on it.

reelquick

No kidding ![X(] Guy at Hobby store was as clueless as I.
Is it OK to run 10/15 % through this?
Thank You, from the newbie 4 stroker.
Fell in love with that sound at the field.

jetmech05

I run 15% cool power in my 4 stroke.....I used a piece of fuel tubing that I ran out of the bottom of the plane aft of the cowl. to vent the nipple on the crank case

SeamusG

Why the vent tube? The volume of space inside the crankcase changes as the piston goes thru its 4 cycles. As the piston goes down on both the intake & power stroke the volume inside the crankcase decreases resulting in an increase of pressure under the piston. The crankcase vent allows the pressure to escape to (balance with) atmospheric pressure. As the piston goes up on both the compression and exhaust strokes the volume inside the case increases resulting in a reduction of pressure. The crankcase vent again allows the pressure to equalize - this time from outside to inside the crankcase.

Combustion blow by accumulates in the crank case. The vent is frequently on the bottom where the blow by accumulates. As the crankcase pressure goes thru its cycles the accumulated oil is pushed out the vent tube. If the vent tube is long - the oil kinda stays within the length of fuel tubing and moves back-n-forth. If the vent tube is short some of the oil exits the tube and wets down the bottom of the plane.

The more ya know the better it gets ...

Used to race a 4-stroke twin motorcycle - needed a puke can at the end of the crankcase vent tube to keep the oil off of the rear wheel - a really good thing.

jester_s1

Seriously the hobby shop employee didn't know what the crankcase vent was for? I hope he's new, otherwise you need a different hobby shop.

Gray Beard

My Feedback: (-1)

I went to the Hobby Town in Vegas last week, asked the salesman for a Great planes adjustable motor mount for a .70 to.90, He asked me if I had the parts number for that? I thought he was joking and said, I was sorry but I had to leave something for him to do. He asked what it looked like as he was sliding the shelves back and forth. He wasn't even looking at any of the parts. He finally decided to look around and found a motor mount, for a big electric? As he was sliding the shelves I said there is another motor mount, he asked me where it was, I said, your hand is on it? It was a Dubro Anti Vibe beam mount. I asked what size it was, he couldn't figure that out so I showed him it was printed on the top of the package, it was too big and I already have some for 1.20s. I finally spotted a couple of the Great Planes mounts after he gave up and I asked what size they were, he didn't know? It was too hard to read I guess, they were for .40.
I know things are tough but if I owned a hobby shop I think I would ask a new employee a few questions just to see if he knew anything about modeling? This person had never stepped foot in a hobby shop yet here is was working the parts counter?? Go figure.
Hobby Town in Vegas may not be a place you want to go shopping in?
If my guy didn't know what a motor mount is just think about what he would have thought about the pressure nipple on a four stroke!!

jetmech05

Hobby Town to me is like a McDonalds....it's a burger but it aint the best.

Gray Beard

My Feedback: (-1)

We have 4 LHS, the Hobby Town, two Hobby People, one on each side of town and we used to have a great old time hobby shop, Nice Twice. Twon stocks some items the People's don't like Glass and micro balloons, there paint selection is the best. This guy they just hired and put behind the counter was a total joke but I didn't say anything, the guy probably really needed a job, any type of job!!
The big shocker was Nice Twice just sold and the new owner moved the shop to a new building around the corner. Smaller shop, one room. The biggest shock of all is where is everything?? A lot of stuff was on consignment to be sold {Nice Twice!} and we all knew that would be gone but the shop now has very little in the way of anything.
It was my go to place for building supplies??Now it's back to on line buying again!
In 15 minutes of us looking around the new shop no one bothered to ask us if we needed help finding something so I don't even know if the guys working the counter would have known what a motor mount was or what the breather nipple on a four stroke was used for.
REALQUICK, you better start reading some books or go into the glow engine forums to read threads so you know what these engines are about, doesn't look like you are going to be getting a lot of info from your LHS either.

acdii

There is a LHS in the next town over that I have lost all confidence in his knowledge, and he is one of those who thinks he knows it all.  I mentioned how my Kadet is flying and that the blurb is diminishing, and he tried to tell me the engine is too hot. [X(]  Um, no, the low speed is too rich, DUH, goes to show he no nuttin bout 4 strokes.  He also said you can use Tygon with Glow fuel.

One thing you do want to check on the 4 stroke, make sure you use 18% oil or better. Quite a few fuel brands have less than 18%, most Cool Power fuels are under 18%. I found Wildcat 2 & 4 Stroke 15% Nitro fuel has 18% oil, and that is what I use in my OS.   If you look at the label on Cool Power, which is what is stocked at HobbyTown near me, it doesnt list oil content. I looked it up online and only one or two specific bottles have enough oil, and the LHS carried none of them. They carry Wildcat though, so I stock up on it from them.

Gray Beard

My Feedback: (-1)

You can use Tygon for glow fuel, it's neoprene you can't use with gas. I have used it on a number of planes over the years, not as the line itself but to extend a line that is too short most the time. So, your hobby shop owner knows more then you think.

acdii

Considering the guy only flys electrics, I had my doubts. There were several things He talked about that I found were false, and my friend has also dealt with him and has come to the same conclusion. His telling me the engine burbles when throttling up after idling for a while was because it was too hot, well, I stopped taking his advice. I know why it burbles, it's a touch on the rich side, and I did that on purpose, the engine isn't too hot, in fact the engine has almost two gallons through it and it looks as new as the day I got it. When I finish this gallon I will retune the low speed  a bit, it should be fully broken in by now.

   In any case I have a small piece in some GF as a test, I put it in last night.  I needed some glow line for a second fuel station for home and he was out and said, oh, use Tygon, mainly because that was all he had, but I already have 8 feet of it.

pimmnz

The only other thing about the vent is not to put too long a tube on the nipple. It's nice to route the oil away from the airframe, but if the blowby oil can't exit the tube on the down stroke, then it simply shuffles up and down, and more and more gathers in the tube and case...you get the picture, and it will cause some running problems. So, a short bit of tube on the exit, please. If you need to move the oil away then exit the short tube into a bigger one, leave an air gap around the tubes, and gravity will take the oil away through the other tube. As for filtering the vent, only if it's really dusty where you are, and the dust can get sucked back into the case, given the amount of blowby air and oil, not a likely scenario.
Evan, WB #12.

acdii

You could also help draw out the oil and gasses by cutting the tube end at a sharp angle with the long end at the front, which will help create a vacuum as you fly. This will help a lot if you have a some what long tube.

jester_s1

acdii- I guess I'm lucky. If I can ever actually get the employees at my LHS to answer a question, they usually know what they are talking about. There's one delightful lady who works the counter a lot who's not an expert, but she knows it and won't guess at an answer she doesn't know. The guys who have to pretend they are experts when they are not are the worst.

acdii

Good hobby shops apparently no longer exist.  There are a total of 3 near me, if you call within a 40 mile radius near.  Out of them, two are a chain, Hobbytown, and both cater to the car crowds, one cars and airsoft crowds, the third is the guy who claims to be an expert, but I caught him in a few mis-information slews.  He told me that if I put a larger nose wheel on the Apprentice than the mains, it would never take off. well he was totally wrong on that one, the plane leaps in the air.  There was another where he discussed a certain ship that sank, He went on and on about the history, how it sank etc, and a few weeks later I watched a documentary on the same ship,and he was totally off on many of the points, the only one he got right was that they raised it.  Ever since then I check and double check all he says.  He doesn't carry much at all for the Glow crowd, just a few gallons of expensive fuel, and some props. I only go in if I need hardware or something that I know he has, but otherwise I get stuff online or the Hobbytown near work.  At least they dont claim to be experts and at least one of them actually flies glow.

jaka

Hi!
Tygon is not so good for anything due to its hardness! But as there isn't anything as soft as silicon that can stand gas (or Diesel) fuel, tygon is the one thing to use in a gasser. Of course Neopren tubing could be used in a gas engine but it isn't transparant so I would choose tygon instead..
Neopren tubbing works for all engines, diesel, gas and glow. Silicon tubing only for glow!

acdii

Well I am only using it for the fueling can, my gasser is already setup and my glow is also, I just need a second glow fueling can setup for when I want to fly at home since I have my flight box at my friend place where we usually fly, so it isn't in my truck stinking it up.  The guy at the LHS didn't have any silicone on a roll and I wasn't about to spend $8 on two 3 foot packages. I have 8 feet of Tygon in my box, so if it works with glow, Im set.

ccberryman

How well does the four stroke case vent work when engine is lying on side or inverted?

acdii

Shouldnt matter, the vent works of the stroke of the piston. on the power or intake stroke it pushes air out, and on the compression and exhaust strokes sucks air in. Having a vent lin connected to it and pointing down, as long as it is short, will compensate for the angle at which it is placed. Magnum engines vent to the intake manifold, Saito out the back plate, OS out the bottom, at least the ones that I have.

JohnBuckner

My Feedback: (1)

Hi accii I can see no reason to not do as you described. The down side of course using tygon as fuel can setup even with glow fuel is its just a bit more ackward working with the stiffer hose.


Wow it definitely a sign of the times and depressing an LHS that does not sell fuel line off rolls For some time now I always kept my own thirty or fifty foot rolls in the shop for my own use. Never have used as much tygon so tend to by that by the foot, maybe I need to start getting rolls of that too? A sign of the time!

acdii

Are you running a gas engine? For the breather, silicone will work just fine, you only need a couple inches of it. Tygon will eventually crack and fall off if there is no fuel running through it to keep it supple. I had a piece from a tank that was laying around after the plane wrecked and it cracked when I tried to use it.