earlwb

Many of the engines tend to spit a lot of fuel out of the carb, or have a fuel standoff right at the lip of the carb like Sport_Pilot mentioned.
On many of my Fox engines after a long time of use, the front of the head shows castor oil varnish stains as well as on the front of the muffler too. It happens with other brand engines as well.
One day I was watching a engine run, I forget which one though, and as each drop of oil oozed out of the front bearing area, I could see it get sucked forward into the prop and then it is slung outwards and off the prop blades from there. Anyway, I am so used to the oil getting on everything that I don't consider it a problem like newcomers seem to do. The bearings tend to last much longer if they have a fresh oil supply and not just stagnant grease that was put in there before they sealed the bearing up. Granted the mean time between failures as is usually quoted in the specs is a long time, but the model engines tend to be pretty hard on the bearings nonetheless. Plus some manufacturers are actually using the wrong bearings for the job as there are bearings designed for the loads imparted to them with a model engine.

For example this engine depicted has a sealed front bearing and doesn't ooze oil out of the front bearing when running.
But you can see the oil residue collecting on the front of the muffler when it is running. That is all oil residue left over from the carb spitting out fuel and oil from the engine.
Usually you don't notice it so much with glow engines as the aluminum color of the metal tends to hide it, so you don't normally see it. So this just happens to be a good example of how much fuel/oil can be spit back out of the carb on a engine, be it a glow, diesel, or gasoline engine. Yes I am thinking about machining up a little intake stack for the carb too.

NM2K

My Feedback: (14)

I'm glad that ya'll reminded me that I bought a used (well used) Fox .50 a short while back with the intention of converting it to Diesel, for which I then purchased a Davis Diesel Development (Hi Bob) conversion head. The engine needs a serious session in the antifreeze tank before restoring it with a new ring and bearings. I might just be better off buying a new one.


Ed Cregger

earlwb

Do check the cylinder carefully, I was going to rebuild a Fox Eagle IV .60 engine but I found the cylinder pretty well worn out too. So I am trading it in for a new one to take advantage of Fox's trade in offer. Putting in a new cylinder/piston./ring and rod along with new bearings puts it over the 50% cost point.

carddfann

I wonder if Fox does anything with their trade-in's. I don't see where they have ever gone thru them and resold them like Mecoa did. Maybe they get some scrap metal value out of them. I noticed that Mecoa dropped the trade-in offer from their website so I guess they just don't want to fool with that stuff anymore. Seems like a waste of effort to me if you're the seller, but I guess what ever it takes to sell a new engine.

NM2K

My Feedback: (14)

I forgot about their trade-in policy. That just might be the best way to go. Thanks.


Ed Cregger

carlgrover

I've run Fox 40s and 50s for over 20 years. I have a bunch of them. I recently sent in a wrecked 50 for a rebuild and they instead sent me back a brand new .46. It is gorgeous. The quality of their engines has improved a million percent since the ones from the 80s.

They are powerful as heck too. Eat just about anything in their class for breakfast except maybe a Jet or Rossi.

hsukaria

How complete would the trade-in engine have to be? What if it is missing a few parts like the carb, or muffler, etc...? Would that still qualify for the discount?

earlwb

Fox says any condition. I assume they would prefer more than 50% of the engine left over to trade though.
ref http://www.foxmanufacturing.com/inde...6eb8a1bb670513
The statement is at the bottom of the page.


I was going to rebuild this Eagle III engine, but the cylinder looks to be pretty well worn out with a weird alternating wear pattern too.
It has a lot of hours on it too. First as a glow engine and then as a diesel.

Elwood

My Feedback: (2)

I called fox today, the. 50 is currently not available. But I am going to trade in my Norvel .09 for a Fox .45!

earlwb

Cool. That is a deal that will be hard to top. Nice going.

Bummer on the .50 but they are hugely popular though. I am not surprised if they sell out fast and have to make more.
But the .45 is a really strong running engine. I am still amazed as to how strong mine pull when I run them and fly them.

carddfann

FYI. I just noticed that MECOA put their trade-in link back up on their website. I know this is Fox, but about half my engines are K&B and the other half Fox. I like'em both. I have a OS 40 that I bought used for my son's trainer and it (the engine) has had it. One day the plug threads got stripped and some metal got into the engine and chewed it up. It lasted my son a couple of years and ran good until that day. Now, I'm thinking about trading it in on a Fox 60. That engine is like a little money burning a hole in my pocket and it'll be good for 50% off a Fox.

hsukaria

It would seem that from a sales point of view, the .50 would sell more than the .45 or any other .4x engine. Is it that Fox is just using up existing old parts stock until it runs out?

Elwood

My Feedback: (2)

I guess we will find out if they sell the .50 again!

earlwb

They actually had to make new parts for the .50 engines. They had used them up years ago when the engine was discontinued.
I had placed orders for a couple of engines and I had to wait a few months before they shipped them as the engines were in the queue.
But usually they give you some extras like extra glow plugs et cetera for your trouble too.

earlwb

Which engines? all the engines I look at have fairly short intake throats on them. You would likely need to have a intake stack of about 2 inches long or longer to help stop the spitting or keep the fuel standoff vapor cloud from sending fuel out onto the engine. When you look at the stacks they put on the gas engines they are quite long. But anything longer that the stock carb intake would help a lot though.

Here is about what one would have to use. But the problem is how to have the prop clear it and not hit it.

carddfann

They have to make new parts in order to offer that 50 gas engine version. However, at $275 (sale price), I'd have to do a lot of flying with it just to hit pay back over the cost of nitro. I wonder how many of the 50 gas versions they've sold. Anybody on here ever try one? It's a bit rich for my budget.

earlwb

I don't know if they have started production and are selling them. They had some kind of a parts problem that has been holding it all up.
I want to get one, but no one has gotten any yet.

hsukaria

I don't think I will pay $275 for a gasser that size either. A .90 (15 cc) gasser is my lowest limit. Fox could design and advertise their engines to run on 0% nitro (which most of them can, I'm told) and attract a lot of buyers who are going away from glow engines because of the high cost of nitromethane.

Somebody here could comment on what the impact to the oil content requirement would be if a glow engine had roller bearing connecting rods like gassers do. That is another detractor to glow engines, people complaining about the amount of slimey oil in the glow fuel. If a glow engine had roller (pin) bearings on the connecting rods, how low of an oil content could a glow engine run on?

If you can run on $10/gallon glow fuel (0% nitro, low oil) vs. $20/gallon glow fuel (high nitro, high oil), suddenly glow engines become much more attractive economically because of lower initial cost (and weight). IMHO

JPMacG

My Feedback: (2)

Oops.

jessiej

I think the Fox redhead 74 and Bluehead 60 had roler bearing cranks.

jess

fujiman

My Feedback: (133)

guys using weed eater and other larger gas engines are converting over the a gasoline/glow fuel mix and having great success with it. the thread here in rcu is ''gas to glow how to'' they're keeping me busy making plug adapters for them!!!!!
the engines MUST have needle bearing rod bearings, and they can get by with very little oil. weedy engines usually run 32:1 up to 50:1 ratio mix depending on manufacture and oil brand used.

earlwb

Most of the glow engines run quite well off of FAI fuel or no nitro glow fuel. The rest of the world, outside of the USA uses no nitro glow fuel or FAI fuel. FAI fuel got its name from the FAI which is the organization for model airplane competition everywhere outside of the USA. Most of their competition events require using FAI fuel, no nitro. So it is a USA only kind of thing where modellers want lots of nitromethane in their fuel. A glow engine runs fine using no nitro glow fuel, but you can bump up the compression ratio to get even better performance with no nitro glow fuel. The USA tends to be in the minority as far as using glow fuel with nitromethane.

Mr Duke Fox once did a article that is quoted quite often in the magazines where as the engine displacement increases the amount of oil in the glow fuel can decrease. A Cox .049 needs 20% oil, but a huge SuperTigre 3250 or 4500 works quite well with 10% oil content. The model engine glow fuel manufacturers have decreased the oil content in their glow fuels to 17% and 16%. The model RC car people have fuel with as little as 12% oil in the fuel (which is why you do not use car fuel in a airplane engine) as the car engines are used differently than airplane engines.

Fox did manufacture .60 and .74 glow engines back in the late 1960's that had needle bearings on the rod. The engines worked quite well and yes you could reduce the amount of oil in the fuel because of it too. But he eventually was forced to discontinue it as it was expensive to make the engines like that and he had to compete with the other brands who weren't using needle bearings on the rods. But he tried. Maybe it was something that was too soon for the world at the time.

carddfann

Sounds familiar. As you probably know, Fox tried designing their engines for no or very low nitro back in the early 80's (if I remember) with the idea that they're doing modelers a favor to help save money with rising cost of glow fuel. But, it didn't catch on that well because people still used nitro that was a bit too much because it was what the imports were designed for or they thought they had to use. Also, most people used what ever fuel the local hobby shop carried. When there was a problem due to wrong fuel (no castor or too much nitro), Fox got the blame. Its risky to design a engine to use a fuel that's outside of what everybody typically uses because people refuse to read and follow instructions so its the manufacturer's fault.

earlwb

Yes that was what happened to the high compression Fox engines years ago. People in the USA just didn't go for no or low nitro fuels. At the time glow fuel was quite inexpensive so people opted for higher nitro percentage fuels. The European engines for many years used to drive USA modellers crazy as they wanted to run high nitro glow fuels in them but the engines were imported as high compression no nitro engines. Now then some engine companies did include extra head gaskets or shims to lower the compression ratio for the USA market. But I remember lots of guys having trouble understanding what the shims were for. OS was probably the first to make lower compression engines for the USA market as a import engine. But OS would sell high compression engines elsewhere. This then had the problem of someone getting a gray market engine from outside of the USA and bringing in and discovering it didn't run off of their 25% nitro glow fuel.

I remember guys getting in fancy European brand engines and they engines ran like crap for them with their 20% nitro glow fuel. I even tried to tell some but the words fell on deaf ears, they simply would not listen.

I still see it today, if 5% nitro works, then 10% is better, and 20% nitro is even better, so thus 30% nitro must be the best. Then they complain about the high cost of glow fuel.

I generally buy and use 5% nitro glow fuel all the time, but I still have a lot of 0% nitro and even 5 gallons of FAI fuel too.
Many of the high compression engines will run fine off of 5% nitro glow fuel and it doesn't cost much more than 0% nitro glow fuel.
But I have used some engines that had really high compression ratios and even 0% nitro glow fuel was tricky to use in them. You had to keep the prop size down and let the engines rev up higher.

But like you said, it really hurt Fox for a number of years to go with higher compression engines at the time. Although the export engines to the rest of the world were met with some success as they didn't use nitromethane in their fuels.

Cougar429

My Feedback: (3)

Fujiman, don't you mean "Glow to Gas"?

There is one manufacturer with a line of what looks simply like gassified glow engines, but claim they were designed that way from the ground up with bushed rods. Personally I agree with you and long term would prefer bearings.