propjobbill

I need help with setting up a fox RC engine it has two needle valves. That may not be the correct way to say it. It has a needle valve plus where the fuel hocks up that also screws in and out. The Engine fires right up but I cant seem to keep it running once it starts.

This is .35 engine, can someone please tell me the right way to set these valves up? For example turn both in all the way and then turn one out X# of turns. I have a .19 fox engine after about 45 minutes I finally got it to run at least acceptable.

If anyone could give me something to go by to save me a lot of time, that would be appreciated.

Thanks Bill

Lightfoot

My Feedback: (1)

You may be able to get the information you need [link=http://www.flitelinesolutions.com/carbs.html]here.[/link] There is a lot of information and appears to be quite useful.

propjobbill

Thanks Howard; That site was a lot of help. For right now I plan on running it wide open at all times but the information on that site should make it a little easier to get it running.

Thanks Bill

firstplaceaviator

My Feedback: (27)

I have had several Fox engines. Most were good engines.
My Fox .40BB Deluxe will hover my Su-do-khoi at just over 1/2 throttle!
It has never given me any trouble in the 16 years I have been flying it.


Call Fox, they are very helpful and easy to work with. 1-877-369-3883

Heres their website: http://www.foxmanufacturing.com

Good Luck!
Doug

kwpcap

My Feedback: (4)

I have run fox engines for years with very few problems. before starting engine open high speed need valve (the one on same side as fuel inlet) 2-3 turns, open throttle just a bit (just enough to see opening in throttle barrel) then blow thru fuel inlet using clean fuel line while opening low speed needle valve (the needle valve on same side as throttle arm) just as it opens enough to let air pass. connect fuel lines and start engine while idling at lowest reliable rpm you can get it at pinch off fuel inlet line if rpm goes up then turn idle/low speed in a couple of klicks, if it dies with no increase in rpm turn low/idle out a couple of klicks, continue doing this while bring idle down to lowest reliable idle until you see about a 50 rpm jump just before it dies then go to highspeed needle valve and adjust for max rpm wide open throttle (do not pinch fuel line for this) when max rpm is reached turn highspeed out about 2 klicks hold airplane straight up nose high if rpm drops off turn highspeed needle out until max rpm is reached then go 2 more klicks out bring back to idle let engine stablize and check low speed again as in previous step. Hope this helps

autoguns

tagged

jeffie8696

Any of the Fox gurus can find me a new connecting rod for my old model 45. Icalled Fox, aint available.

earlwb

I can only suggest to watch Ebay. Every now and then the connecting rods pop up for sale or auction.
But pay attention to the part number though. Fox did change the crank pin size a couple three times. If I remember right they had a smaller crankpin size on the old bushing 40's and 45's than they used on the ball bearing engines. the newer engines may have another different size too, but I forget now. Also the early engines have a exhaust port hole spacing that is about 2mm narrower than the later model engines. That makes it a hassle to find a older style muffler to fit the early engines.
You do know you can trade in the old engine with Fox for a new one at half price?

jeffie8696

Iknow about the trade in , Iwould take advantage but it would be much cheaper to just get a new rod. Other than the rod this engine is almost brand new.
Igave it to a buddy and he somehow managed to screw up the rod. Has hardly been run.
Ibench tested it when Ifirst got it and was really impressed at how easy it was to get a really low idle and made good power.
Ihave a muffler, Imade an adapter and used an Enya muffler.
Iwould hate to see a beautiful engine go to waste.

earlwb

That is a really cool setup for the muffler. Nice job.

Konrad

How did your buddy mess it up? About the only ways I know is hydraulically locking the engine or running non castor oil fuels with oil content less than 20%. If it was hydraulically locked I'd be concerned with cracks in the crankpin tower or cracked piston. As a former Fox dealer I have a lot of loose parts, rods included. If you can get us a photo I might find (visually) one that fits. What I'd be interested in is the oil feed on the crank end. Is it a slot or a drilled hole? I also assume it has a non bushed bore on the piston end

All the best,

jeffie8696

Thanks Earl, Idesigned it and my buddy the machinist made it.

Konrad, thanks for the help. If you need any measurements let me know, Iwill get the best I can with just a caliper. It is egged on the big end , the crank pin looks good , have no idea what he did since the rest of the engine looks fine. Maybe Ijust got a soft one, wish it was bushed.

Konrad

Is it bent or out of round?

Dam, it is the slotted style, that is going to be a challenge! Do post the bores and the center to center. I'm sure it will help me or somebody else.

If you use castor oil and at a proper percentage the non bushed rod should work fine. The rod I used in my 27K plus RPM F3D engines had only a bushing on the crank end. These engines used 20% oil and 100% castor.

jeffie8696

From just my caliper it says it is .17mm out of round at the crank pin bore. Looks like 5.49mm dia at the crank bore, 4.62mm at the wrist pin bore and 37.93mm on centers.
No idea what he put in it, I like plenty of lube, it was broke in (initially) by me with Sig FAI fuel, ran awesome.

earlwb

Sounds like someone tried using RC Car fuel, high nitro, low oil content. Car fuels can come with less than 12% oil, usually all synthetic oil too.
I have seen guys use 25% nitro with 8% to 10% oil in their RC cars before. Some of the fuels advertised run 20% nitro with 12% to 13% oil (100% synthetic). They tend to like synthetic oils to keep the oily mess down as well as less oil is less to clean up too. RC car engines typically have a shorter lifespan airplane engines, due to their exposure to dust and dirt, and extremely high RPM bursts. Plus everyone gets into racing cars as well.

I looked through my boxes of parts but I didn't have any slotted rods left. I took a look at some possible replacements, but they all measured about 41.xx mm in overall length though.
Sorry

jeffie8696

Thanks Earl. I have a bout a half dozen assorted rods there and nothing came close. Might have to have it bushed, anybody know who does that kinda thing?

w8ye

My Feedback: (16)

Keep your eyes open for a local guy who can do this work for you from his basement or out building

earlwb

I have in the past made my own connecting rods. It didn't turn out too bad. Nothing fancy to show, but they worked. One can do it with a drill press and a hacksaw, a set of files and a good assorted pile of different size drill bits.

What I did was take a piece of scrap aluminum stock, and using a set of drill bits, I would use a drill press and drill a hole and check to see if the crankpin fit the hole Ok or not. Then repeat using different drill bit sizes until I got one that was about right.  I would then use a center punch to mark the center to center points on the piece of aluminum, I would drill the holes and double check them again using the crankshaft crankpin and wrist pin. Then if it looked good, I would carve it out, and file it to shape. Of course using a milling machine would work good too.
To put in a bronze bushing, you drill out a larger hole and heat the metal up and freeze the bronze rod piece and then lightly press it in. let it all cool down, then do the same thing as mentioned above.

if you get the deluxe large drill bit assortment, you can mostly find a drill bit to match up with the correct hole sizes. The problem with a drill bit is it tends to drill a hole slightly larger than its size. So you might wind up with a slightly smaller drill bit. I have also spun a drill bit in a drill press and carefully ground them down a little bit to make them slightly smaller too.

Ideally one would use reamers to get the exact size, but reamers can get expensive as you collect a bunch of them over time.
Oh yeah, on the crankshaft side you need to camber the hole slightly for the crankpin to clear. Technically you don't really have to trim down the rod to make it thinner in the middle all that much, just enough to clear the crankcase, etc. Then you can drill the lubricating access holes or even use a dremel to put in the slots if you like.

I keep meaning to make a rod for my old copy of a Mills .075 diesel engine, but I never seem to get around to it. Heck I have a old Fox bushing 40 that  I need to make a rod for too, but I never got around to that either. I had other engines I could use instead.

Konrad

Sorry Earlwb,
But one should never use a drill for this kind of work. A drill wanders a lot and does not cut a round hole. A set of reamers is more appropriate and if you really want the best a hone should be used (not critical for this sport application).

As was mentioned Jeff knew a machinist. He might have the cutters needed to make a new one. It is a simple high school metal shot project. They still have metal shop in high schools? Do they teach any vocational skills in high schools?

All the best,

Konrad

blw

My Feedback: (3)

If they worked and held up, well.........

earlwb

I really want to see a pic of a hone for those little tiny holes in a connecting rod for a glow engine. Does it have two or three cutters or hone blades on it? the springs ought to be really cool too? Do you spin it up in a milling machine or lathe, or do you work it by hand? what grade hone material do they use?

yeah i did mention reamers are the way to go, maybe I should have emphasized it more , but they may be hard to get, plus you'll likely have to grind a few down to size before you can use them. anyway drill bits do work, even if they aren't perfect for it.

A long time ago, i did sit down one day and make a couple of rods the hard way. The engines worked with the crude rods. That was back in the days before we had internet, and the hobby shop owners didn't know how to get parts for the engines at the time. I had bought the engines in Japan when i was stationed there, but they were never sold in the USA by anyone. At the time i had them a little bit snug, so i used some lustrox fromFox to lap them in some to get them a little bit looser.

I can't tell you how long they'd last as someone burglarized my home and stole a lot of my RC stuff at the time. The engines went with the airplane fuses. The scum took the planes and rc stuff but left the wings.. so i wound up scratch building some fuselages to use the wings on. some other RC flyers in our club at the time gave me a older model proportional radio and the Fox Bluehead 60 to use while i was getting back into it again. I still have that .60 engine of course. I had posted pics and videos of me running it a little while ago.

I do have a fair collection of assorted reamers nowadays, but I swear, no one uses the same size hole anywhere. they always want to be different. sheesh. You'd think they would have standardized on it or something. heck even the engine manufacturers do it, they keep changing the holes on the engines when they redesign them. You know, one time the crank pin is made larger, then later they make it smaller again, and then later they make it larger again.

Konrad

So you did.
The pin hones I've used are single shoed.
Stone grade depends on material.
One can also lap a cross hatch pattern for oil retention.

All the best,

Konrad

jeffie8696

Luckily Ido have a master machinist as a friend but Ihate to impose on him, he is understandably busy. There is no hurry , Ican probably just add a bushing to the rod Ihave and be well ahead of the game. Thanks for the advise.

Konrad

True Masters are a very rare find. I only made it as far as a Journeymen.

I too will look to see what I can find when I make it back home.

All the best,

Konrad

NM2K

My Feedback: (14)

Isn't "Journeyman" as high as it goes, officially? Then again, what do I know? (smile)

***Uh-oh, somepin' be wrong with someone's software. I was responding to Konrad's statement that he only went as high as journeyman machinist.


Ed Cregger