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Old 06-24-2016, 04:06 AM
  #4676  
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C, have you pulled that screw to see what's in there, here's a tip, if you have access to an MDS remote needle, they are excellent and can withstand the pressure of a Cline regulator setup. The Cline setup puts a serious bulge in those stiff walled Sullivan tanks.Here is one pictured on a Fitzpatrick .61.
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Old 06-24-2016, 04:25 AM
  #4677  
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I have been using the EVO RNV on most of my 40 class motors to get the needle away from the prop:

https://www.google.ca/search?q=evolu...w=1280&bih=599

Think I have at least one more in spares, (intend to do that mod to a NIB OS 45FSR getting mounted to a -190 this afternoon so hope there is another).

I should at least check there is a good seal with the cap bolt and may fab a gasket for that one, as well. Would like to compare the two carbs. Biggest problem is the need to remove the engine to get at the mounting screws.
Old 06-24-2016, 03:23 PM
  #4678  
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O/K. Think I have it figured out. Took some fiddling to get stable idle when glow removed and originally sobbing rich on high end. Once set still sagged nose up so increased the pump approx 3/4 turn. Now I have good idle, transition and full tilt regardless of attitude. Another success is no leaks from either needle or fuel inlet housing.

Having said that thought this was the case earlier, but had bogging on throttle up and it sagged in the air. Hope I have better luck this time.

In fact, off to the field for the "International Bipe Day" tomorrow morning. Unfortunately with two of them stuffed in the van and another to maiden no room left for this one. Will have to wait till out again.

And this leaves me with another question: I found movement in the throttle barrel which would obviously affect LS mixture. Seems stable. Just wonder if I am going to have to deal with groove wear. No room for a spring in this one.

Last edited by Cougar429; 06-25-2016 at 04:27 PM.
Old 06-25-2016, 04:14 PM
  #4679  
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I tried to remove the prop driver on my Fox 45 with heat and prying it with 2 screwdrivers, but no dice. The prop driver is in there real tight. I was heating it with a heat gun. Should I go to oven or crockpot for loosening the prop driver?

Another sad story: I was flying my plane with a compact Fox 40 (C-case) that has the iron piston and stell sleeve. I flew it a couple of tankfuls and then suddenly it began to act up. I noticed that there was some dirt that got on the engine. I cleaned it thoroughly at home and took it back today for flying. The engine now quits suddenly at WOT even though it starts, idles, and transitons nicely. Seems like a compression loss when the engine heats up?

Any ideas to help with either engine is greatly appreciated.

Despondent it Detroit
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Old 06-25-2016, 04:20 PM
  #4680  
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Originally Posted by hsukaria
I tried to remove the prop driver on my Fox 45 with heat and prying it with 2 screwdrivers, but no dice. The prop driver is in there real tight. I was heating it with a heat gun. Should I go to oven or crockpot for loosening the prop driver?

Another sad story: I was flying my plane with a compact Fox 40 (C-case) that has the iron piston and stell sleeve. I flew it a couple of tankfuls and then suddenly it began to act up. I noticed that there was some dirt that got on the engine. I cleaned it thoroughly at home and took it back today for flying. The engine now quits suddenly at WOT even though it starts, idles, and transitons nicely. Seems like a compression loss when the engine heats up?

Any ideas to help with either engine is greatly appreciated.

Despondent it Detroit
A lapped engine usually won't exhibit the compression loss when hot like an ABC engine will. How does the engine feel when turning over cold and then turning over hot? Will it do the same thing if the HS needle is set a fair bit fatter? Did you read the glow plug? Try a new glow plug? Head bolts still tight?
Old 06-25-2016, 04:36 PM
  #4681  
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Pull the HS needle and check flow. You are on the LS needle until 3/4 throttle so good idle and transition may not show a lean condition once on the High Speed.

Only idea I would come up with to get that drive washer off would be to stick the engine in a bag and leave it in the freezer overnight, then while still cold heat the washer as quickly as possible. The hot glycol dunk may help if this does not work as it would tend to loosen any dried lube that may be locking it together.

Personally I modded a battery terminal puller like the one in the pic and have used this to remove drive washers on everything up to Saito 125's and YS 120's, although a bit of creative work is required when the threaded portion gets longer.

This will usually break them loose and even tension while heating can have them snap if difficult.
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Old 06-25-2016, 06:05 PM
  #4682  
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Originally Posted by 1QwkSport2.5r
A lapped engine usually won't exhibit the compression loss when hot like an ABC engine will. How does the engine feel when turning over cold and then turning over hot? Will it do the same thing if the HS needle is set a fair bit fatter? Did you read the glow plug? Try a new glow plug? Head bolts still tight?
I suspect that it might have leaned out in flight. I had it running extra rich later because I could tell it was getting quite hot even though it worked well with that setting before. At first when it started acting up, the glowplug got scortched, looked like the coil got scrambled. I replaced it with a new plug and ran it rich(er). It would run normally for about 2-3 minutes at WOT and then suddenly quit, regardless of HSN setting. The idle and transition worked well. When hot, there was practically no compression. But when cold it has a good "pop" from compression. I checked the head bolts and were on tight.

Distraught in Detroit
Old 06-25-2016, 06:39 PM
  #4683  
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I might be on the wrong track, but what fuel are you running? If over 5% you may be detonating and destroying the plugs. That would also account for the overheating.

I've had to open up the combustion chamber, a trick described in the notes now at Fayeteville:

http://www.fayettevillercclub.com/id59.html

If not had a boo at these they cover some good points on the 40.
Old 06-25-2016, 06:49 PM
  #4684  
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Originally Posted by Cougar429
I might be on the wrong track, but what fuel are you running? If over 5% you may be detonating and destroying the plugs. That would also account for the overheating.

I've had to open up the combustion chamber, a trick described in the notes now at Fayeteville:

http://www.fayettevillercclub.com/id59.html

If not had a boo at these they cover some good points on the 40.
From the start I have used fuel with 5% nitro and 20% castor. I have a filter on the fuel line. I did notice however that dirt had gotten between the prop driver and the crankcase. I am wondering if it got inside the front bearing, which is unsealed. But the bearings feel smooth. However, when I was starting the engine, I could hear a scratchy/high pitch sound like metal on metal scraping. I have not opened up the engine except to look and the cylinder liner, which doesn't have any scrapes or scratches. I thing I will completely disassemble the engine tomorrow to look at the lower end. This engine had been running quite well with the fuel and giving good performance when it suddenly began quitting.


Destroyed in Detroit
Old 06-25-2016, 11:40 PM
  #4685  
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Hsukaria,

I also replied directly to your post as forwarded to my email. To repeat one or two things for the general audience:

Strip down the engine (remove piston, rod, sleeve.) Set rear face on a flat board. Shield the shaft end (prop nut a turn or two above shaft, block of wood as contact surface) then tap firmly on the prop end of the shaft. Once the collet loosens, it releases the driver shield.

Your fuel may be a problem. Is your fuel a commercial product, or your own making? What we "civilians" can buy isn't always of the quality or freshness that commercial fuel brewers get. And in humid, hot conditions fuel can absorb water from the air, or go off for other reasons.

20% castor is not ideal for iron in steel engines; 25% total oil should do better (you can make up the difference with synth.) I had some fuel ~25+ years ago in which the castor 'went bad' and visibly darkened in the liquid fuel. Suddenly! It formed crystalline, abrasive particles at the sleeve ports and made a scraping, screeching noise while spewing sparks! (No mufflers back then.) Seized hot after only several seconds... I fly CL, no throttle to shut it down on that one... The parts that suffered this were able to serve after cleanup!

Iron/steel engines CAN overheat and either feel about to seize or very low compression when they stop; I've seen it and done it in hot, humid mid-west summer conditions. They usually recover if allowed to cool several minutes to ambient temps. Proper castor% is the best defense.

Have you bench-checked the throttle setting? That lets you shut down instantly if things go wrong. After you cleaned it up, did you go through the throttle setting procedure recommended for the carb you're using? (I assume you checked that fuel passages and filters flow properly and if it is a flexible clunk tank, that the line is not crimped over...)
Again, luck!
Old 06-26-2016, 03:46 AM
  #4686  
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Originally Posted by hsukaria
I suspect that it might have leaned out in flight. I had it running extra rich later because I could tell it was getting quite hot even though it worked well with that setting before. At first when it started acting up, the glowplug got scortched, looked like the coil got scrambled. I replaced it with a new plug and ran it rich(er). It would run normally for about 2-3 minutes at WOT and then suddenly quit, regardless of HSN setting. The idle and transition worked well. When hot, there was practically no compression. But when cold it has a good "pop" from compression. I checked the head bolts and were on tight.

Distraught in Detroit
Well, you were too lean for sure. No compression when hot is a bit scary, but if it comes back cold, it might be okay. Always richen the needle and re-tune each time you go out to fly on a different day. Never assume that a setting from one day will work on the next.

Tight head bolts are a good sign, it wasn't run way too hot...
Old 06-26-2016, 04:13 AM
  #4687  
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Lou - don't you think 25% oil would be more appropriate for a smaller engine - maybe the .15-.20 class? A .40 lapped or not should be just fine on 20% castor oil. I looked at the paperwork for my Mark IV Fox .40 (one of the first compact .40s) and it states Gold Star (0% nitro - other web links show the Gold Star fuel to be 5% nitro...). Dukes Fuel (10% nitro), or Ten Plus (10% nitro) were suitable. I don't recall off hands at the oil content of those fuels are - I can't find the paperwork that stated it. The paperwork did not list a minimum oil content for the engine. The only paperwork that listed a minimum oil content was for the B-case .45/.50 at 17% oil minimum. My Mark V .40 has the head button with the tiny bowl and mega huge flat squish band. It ran on 5% nitro just fine as did my ABC .40 did with the same button. If one can find the cone shaped head button, then you have a lot more latitude for nitro as that head is suitable for 10-15% nitro. I've run 20% nitro without issue on the test bench, but may be too much once in the air.

For the heck of it, I attached a price list from 2008 for Fox fuels. Really just for no other purpose than to just post published stuff from Fox since there isn't much in the way of documentation from Fox on the web it seems. And FWIW, the Mark VI .36/.40 engines have the same fuel recommendations.
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Old 06-26-2016, 05:07 AM
  #4688  
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I might have to use my own advice and difficult as it is pull the motor and open it up, (or at least yank the head). Even though I went through at least a half a gallon or more in break in before mounting with the Perry setup and it spins the Graupner strongly, I find compression is pretty limp.

After the experience burning out the back of the piston with the original head button design am wondering why this is so.
Old 06-26-2016, 01:11 PM
  #4689  
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Originally Posted by 1QwkSport2.5r
Well, you were too lean for sure. No compression when hot is a bit scary, but if it comes back cold, it might be okay. Always richen the needle and re-tune each time you go out to fly on a different day. Never assume that a setting from one day will work on the next.

Tight head bolts are a good sign, it wasn't run way too hot...
I wish I knew the root cause. I was running it in a hot day, so re-tuning was necessary. I flew it twice before on the same day with no problems. But then starting the engine for the third flight, it did get lean, but at the same time I felt scratchy dirt behind the prop hub (flying it in a belly lander plane). It might have been the extra friction from the dirt causing the engine to heat up more? No telling. I just hope it can be revived because there are no replacements. I have both the B-case 45 and the C-case 40 engines. I like both, but the small 40 is so unique because of the small size. I wish we could get spares like the old days.

Devastated in Detroit

Last edited by hsukaria; 06-26-2016 at 01:15 PM.
Old 06-26-2016, 03:32 PM
  #4690  
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Originally Posted by hsukaria
I tried to remove the prop driver on my Fox 45 with heat and prying it with 2 screwdrivers, but no dice. The prop driver is in there real tight. I was heating it with a heat gun. Should I go to oven or crockpot for loosening the prop driver?


Another sad story: I was flying my plane with a compact Fox 40 (C-case) that has the iron piston and stell sleeve. I flew it a couple of tankfuls and then suddenly it began to act up. I noticed that there was some dirt that got on the engine. I cleaned it thoroughly at home and took it back today for flying. The engine now quits suddenly at WOT even though it starts, idles, and transitons nicely. Seems like a compression loss when the engine heats up?

Any ideas to help with either engine is greatly appreciated.

Despondent it Detroit
The prop driver is on a tapered shaft, you may think it is really stuck until it pops right off. Put the engine in the freezer, after it's cold quickly heat the driver with a propane torch until spit sizzles. It should pop right off. The trick is to heat the driver without heating the shaft. If you don't do it right you'll have to start over. Once you get it right you will always know how to do it.
Old 06-26-2016, 06:35 PM
  #4691  
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I had a bad experience the first time I tried synthetic fuel in a couple Iron steel engines, a Fox .59 cl modified with an old Johnson Automix carb, and a (sorry bout that) McCoy Redhead .35. The fuel, a commercial mix, was supposed to be 20% oil, all syn. Both engines overheated almost immediately. Very cooked look around the cylinder fins. In fact the redhead is now a black head. The Fox suffered the most, to cut it, I had to work the fuel line off the barbed fitting, needle valve in or out in my hand didn't do anything. Both seemed to loose a little compression cold, but still run much the same as they did before.
Several years ago, when the local HS had some problem getting all castor fuel, another older flyer talked me into getting some 18% synthetic, and adding about 6 ounces of castor. A modified (fortified?) gallon then gave me 134 ounces of oil blend fuel, roughly 29 ounces of oil, and roughly a 21% lube. No trouble since. In fact, I even add 6 ounces (if it fits!) per gallon of syn/castor blend to bring the oil at least close to 20% for almost anything I fly, including lapped, ring, and ABC. Even when I find 20% lube, 6 ounces of castor gives me almost 24% for the old Fox, Veco, McCoy, K&B, and Jonson lapped CL engines.

Last edited by 50+AirYears; 06-26-2016 at 06:37 PM. Reason: Mind wandering with advancing years!
Old 06-26-2016, 07:23 PM
  #4692  
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Originally Posted by 1QwkSport2.5r
A lapped engine usually won't exhibit the compression loss when hot like an ABC engine will. How does the engine feel when turning over cold and then turning over hot? Will it do the same thing if the HS needle is set a fair bit fatter? Did you read the glow plug? Try a new glow plug? Head bolts still tight?

Lapped engines are more prone to compression loss when overheated than ABC engines. In fact that is why ABC engines were invented,. Many a time I have had a Fox Stunt engine barely running because it was running lean and hot, but still running. They are ususually OK after that but not good for the engine,.
Old 06-26-2016, 07:29 PM
  #4693  
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Originally Posted by Sport_Pilot
Lapped engines are more prone to compression loss when overheated than ABC engines. In fact that is why ABC engines were invented,. Many a time I have had a Fox Stunt engine barely running because it was running lean and hot, but still running. They are ususually OK after that but not good for the engine,.
I guess I haven't ran one hot enough then... Wait, I thought brass expands more than iron or steel does....

Usually when you get 'em hot is when the castor is supposed to turn into the mystical varnish that everyone speaks of when lapped iron engines come up in conversation.
Old 06-27-2016, 03:53 AM
  #4694  
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Wait, I thought brass expands more than iron or steel does....
Wait, I thought brass expands more than iron or steel does....
Yes and the aluminum piston has a slightly higher expansion rate. With iron on iron the expansion rate is the same but that means the larger object expands more than the smaller so the almost 0 gap between piston and cylinder grows larger,. With an aluminum piston allow matched with the right cylinder brass alloy the gap is closed off
somewhat.

Fox Stunt .35's have very little cooling fin area so they overheat quickly on a lean run.

Last edited by Sport_Pilot; 06-27-2016 at 03:56 AM.
Old 06-27-2016, 05:31 AM
  #4695  
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Brass expands faster than aluminum, and it gets looser as it heats up as in an ABC. That is the great part of the ABC. A few lean runs on a steel set can ruin them. An ABC has a better chance of recovery. AAC is ok too. better for pit stop restarts, but does not have the effect of saving a motor like ABC. A chromed steel liner is a good thing too, after it has worn out. It seems to hold the heat from a lean run better than a regular steel set. Lean runs are bad news though all around. Having flown a lot of control line, a lean run in steel P/C has ruined a few motors on me. Lots of castor is ok, but I normally use it after it is worn out, just to make the motor useable. The old steel ones, I normally liked to lap out for a nice fit so they would not seize up, and they would break in easier. Of course I flew speed, and friction was the major reason for a loose fit. In some cases castor was forced on us in the FAI speed event. It was ok but needed to be devarnished quite often. TDs are bad for that too. That was a cause of overheating too. This being a Fox thread, I would have to say that could be the cause of it overheating when hot, but having said that, Fox users seem to swear that the Foxes need the varnish. I will stay out of that one.

Last edited by aspeed; 06-27-2016 at 05:34 AM.
Old 06-27-2016, 05:52 AM
  #4696  
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Originally Posted by aspeed
Brass expands faster than aluminum, and it gets looser as it heats up as in an ABC. That is the great part of the ABC. A few lean runs on a steel set can ruin them. An ABC has a better chance of recovery. AAC is ok too. better for pit stop restarts, but does not have the effect of saving a motor like ABC. A chromed steel liner is a good thing too, after it has worn out. It seems to hold the heat from a lean run better than a regular steel set. Lean runs are bad news though all around. Having flown a lot of control line, a lean run in steel P/C has ruined a few motors on me. Lots of castor is ok, but I normally use it after it is worn out, just to make the motor useable. The old steel ones, I normally liked to lap out for a nice fit so they would not seize up, and they would break in easier. Of course I flew speed, and friction was the major reason for a loose fit. In some cases castor was forced on us in the FAI speed event. It was ok but needed to be devarnished quite often. TDs are bad for that too. That was a cause of overheating too. This being a Fox thread, I would have to say that could be the cause of it overheating when hot, but having said that, Fox users seem to swear that the Foxes need the varnish. I will stay out of that one.
Sorry but aluminum expands faster than brass and ABC liners keep or nearly keep their clearance as they expand. Iron sleeves and pistons get looser as they expand not ABC.
Old 06-27-2016, 06:26 AM
  #4697  
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I think the expansion rates of a given metal is highly dependent on the specific alloy.

Ive been using all castor in most of my engines for many years now. Oddly enough, the only engines I find varnish in are my ABC arc car engines. None of my aircraft engines regardless of cylinder/piston material, have any varnish. Carbon, yes... And FWIW, I choose the oil content moreso based on displacement than cylinder construction. Smaller engines get more oil than larger engines with one exception being sleeve bearing cranks. Those engines seem to run better with more oil; the caveat is with the higher compressed engines, higher oil content usually requires dropping the nitro a bit. For a .40 - I'd use 20% oil. If using a predominately synthetic fuel, I would add some castor and drop the nitro a little bit. In a Fox - if it has any head button besides the cone shaped low compression heads, I wouldn't use more than 5% nitro anyway. I have a low nitro head and a high nitro head for a compact .40, but I never tried using more than 5% with the high nitro head.
Old 06-27-2016, 06:34 AM
  #4698  
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Originally Posted by Sport_Pilot
Sorry but aluminum expands faster than brass and ABC liners keep or nearly keep their clearance as they expand. Iron sleeves and pistons get looser as they expand not ABC.
You are correct that aluminum expands faster than brass. That is why high silicon aluminum is used for pistons, often over 22%. It provides better wear resistance than steel too because of that, and the coefficient of expansion is lowered from standard aluminum alloys. I am not sure what grade of brass or bronze is used on liners.
Old 06-27-2016, 07:24 AM
  #4699  
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That is why high silicon aluminum is used for pistons, often over 22%.
The high silicon aluminum does expand less than most other aluminum alloys in fact all but beryllium alloyed aluminum. Most silicon aluminum alloy's have a slightly higer expansion rate than most copper or brass alloy's. The actual alloy's used still require the aluminum piston to expand slightly more than the brass sleeve.
It provides better wear resistance than steel too because of that, and the coefficient of expansion is lowered from standard aluminum alloys.
Silicon is harder than steel, but that does not necessarily means it wears better. In fact at very high temps the alloy will break down causing some silicon to come out of solution and act as an abrasive. The looser clearance and thicker oil used (100% castor) can result in all iron engines to last much longer than an ABC engine.
Old 06-27-2016, 07:48 AM
  #4700  
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About 6 years ago I bought all Fox parts from a shop that had been in business since the late 40's. He was the go to guy for engine repair. I'm thinning my herd now, so if anyone is interested let me know and I will send an inventory. These are new in Fox containers. I'm interested in selling the entire box of parts. Cheap. Thanks for looking. Richard

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