RE: COX .049 plane engine Fuel  
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All Forums >> Glow Engines, Gas Engines, Fuel & Mfg Support Forums >> RC Fuels >> RE: COX .049 plane engine Fuel
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RE: COX .049 plane engine Fuel - 8/1/2007 6:11:48 PM   
burtcs


 

Posts: 456
Joined: 12/20/2004
From: Corvallis, OR, USA
Status: offline 		downunder:

Maybe you've never seen a COX Conquest, it has a rod and pin, maybe some of their prototypes also.

regards - Steve B.

(in reply to downunder)
       Post #: 26

RE: COX .049 plane engine Fuel - 8/1/2007 9:35:01 PM   
Jezmo



Posts: 657
Joined: 6/26/2006
From: Spring, TX, USA
Status: offline 		The Conquest is also a .15 size engine. I have never laid eyes on a Cox .049 with a con-rod either. Not saying they don't exist but I know some other firms made .049's that did have regular con-rods like the big ones, Win-Mac comes to mind, just never saw one in a Cox.

Good day all.

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(in reply to burtcs)
       Post #: 27

RE: COX .049 plane engine Fuel - 8/1/2007 9:56:28 PM   
gkamysz


 

Posts: 1405
Joined: 6/24/2003
From: Crystal Lake, IL, USA
Status: offline 		I have a .15 Medallion cylinder with a piston with wrist pin. I got it in a lot with several other Medallions piston liner sets that had the typical ball and socket.

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Greg

(in reply to Jezmo)
       Post #: 28

RE: COX .049 plane engine Fuel - 9/26/2007 6:33:55 PM   
1705493-AndyW


 

Posts: 1835
Joined: 1/17/2003
From: Timmins, ON, CANADA
Status: offline
quote:

ORIGINAL: Jim Thomerson

Cox engines don't need much break in because of the precision with which they are made. They are in fact little jewels.


Jim,

They ARE jewels but I'm wondering about the fits that came out in the last number of years. Decade? I'll take a brand new engine or piston and cylinder set and run it in with a tank or so a tad rich then peak it out with no problems. This shows that not much break in is required due to a light fit. However, in my opinion, it's been TOO light. Evidence of that is that after extensive running, the piston shows signs of staining on the sidewalls of the piston. This indicates a lot of blowby.

The precision is there because you can swap out any piston to any cylinder and the same situation occurs. I'd kind of prefer the reverse so that you could mix and match the P and C to get a just right tightness that you could carefully break in for a perfect fit, best power and long life.

Elsewhere is mentioned that all the Cox machinery has been sent to China. Can anyone confirm this? I sure hope they do their homework and give us fits that require a break in.

< Message edited by 1705493-AndyW -- 9/26/2007 6:54:26 PM >

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(in reply to Jim Thomerson)
       Post #: 29

RE: COX .049 plane engine Fuel - 10/1/2007 12:01:37 AM   
lukesp



Posts: 355
Joined: 4/24/2006
From: BrisbaneQueensland, AUSTRALIA
Status: offline 		The piston/cylinder fits of most Surestarts is poor compared to previous Cox efforts. There IS a lot of blowby, in fact about one in ten Surestarts are good, the rest are fairly poor. I believe this is why Cox specifies 20-25% nitro these days. The production cylinder previous to the Surestart seemed to be better, but the cylinders/pistons made before the slit exhaust era are good to excellent.

Which leads me to another point, taper. The amount of pre-slit engines I have that exhibit taper is very surprising considering tapered bores were only claimed for the TeeDee P/L. I'm talking all types, from number 1 cylinders, numbers 2's , etc. exhibiting tapered bores. Anyone else noticed this?
Not one slit exhaust engine that I own regardless of configuration shows any sign of it.

Oh, to remain on topic, another good reason to avoid 100% synthetic oils is crankcase bush wear. Castor oil seems to help there.

(in reply to 1705493-AndyW)
       Post #: 30

RE: COX .049 plane engine Fuel - 10/3/2007 4:13:18 AM   
glowplugboy


 

Posts: 574
Joined: 12/26/2001
From: Pasadena, TX 77505/77508, TX, USA
Status: offline 		Take a look at "Rocket 24" from GCBM R/C Models Inc. 24% nitro, 17% all castor lube. Perfect for .049's. They will sell you a quart or a 12 quart case. www.gcbmrc.com

(in reply to lukesp)
       Post #: 31

RE: COX .049 plane engine Fuel - 11/18/2007 12:21:04 AM   
MARTINSR


 

Posts: 8
Joined: 11/18/2007
From: San Francisco Bay area, CA, USA
Status: offline 		Hello guys, this is my first post here so bare with me. I have dug an old PT-19 out of the attic and my 10 year old wants to see it run in the worst way. I have went thru getting a new glow plug only to find out that my battery case was just too dirty and wasn't getting juice to the clip. I went and bought some fuel and a few other things to get the fuel into the tank and I was ready to hear that little .049 fire up but nooooooottttthhhinnng..... I have tried for quite a while and it gives some little splutters but that is it. I had cleaned out the motor in thinner, reassembled it and installed the new glow plug and gasket. I wore out a few of these little motors when I was a kid and would start them up on a moments notice (a few times in my bedroom ) but I am getting pretty discouraged with this thing I want to go fly it with him so bad.

Do you have any tips? Is there a better forum to post this question?

The fuel I bought is Byron 1/2A fuel with 25% nitro and 16% lubrication. I thought it was a little low on the lub after reading this thread a week ago, but thought if it was at least it would fire easy, but nothing..

Brian

(in reply to glowplugboy)
       Post #: 32

RE: COX .049 plane engine Fuel - 11/18/2007 2:39:43 AM   
w8ye



Posts: 16715
Joined: 12/11/2001
From: Taylortown, OH, USA
Status: online 		If it pops but never runs, there is dirt under the reed valve. That's the little tin thingy behind the crankshaft leading to the carburetor.

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       Post #: 33

RE: COX .049 plane engine Fuel - 11/18/2007 5:56:17 AM   
rcdude7


 

Posts: 879
Joined: 4/12/2003
From: Maryland
Status: offline 		I just bought a quart of sig champion 25% nitro fuel from tower hobbies for my cox engines. This fuel contains 20% lube, that is 50/50 klotz and castor. I had always thught that ALL castor is the prefered, but this is what tower carries for 1/2A engine fuel. Should I add more castor to this fuel or just run it as is?

Mike

(in reply to 1705493-AndyW)
       Post #: 34

RE: COX .049 plane engine Fuel - 11/18/2007 6:09:10 AM   
MARTINSR


 

Posts: 8
Joined: 11/18/2007
From: San Francisco Bay area, CA, USA
Status: offline
quote:

ORIGINAL: w8ye

If it pops but never runs, there is dirt under the reed valve. That's the little tin thingy behind the crankshaft leading to the carburetor.



I'll pull the thing apart again, geez I used to know those motors like the back of my hand but I don't remember them having any kind of "reed valve".

Now, I see that Mike refered to this engine as a "1/2A" is this a name for the .049?

I seemed to remember this motor running in a counter clockwise and you started it by turning the prop in a clockwise against the spring that would then spin it counter clockwise. This is what I seem to remember from 30 years ago but after putting this thing back together in what looked like the right way the prop must be spun counter clockwise and the motor will run clockwise. The prop, everything looks correct in this way, but I thought I should ask.

Brian

(in reply to w8ye)
       Post #: 35

RE: COX .049 plane engine Fuel - 11/18/2007 6:07:06 PM   
w8ye



Posts: 16715
Joined: 12/11/2001
From: Taylortown, OH, USA
Status: online 		Yes it is a 1/2A engine

The engine will run in either direction with equal vigor

The reed valve is at the rear of the the crankcase behind the crankshaft. It is held in place by a spring type cir-clip. Remove and clean well. Install the reed with the opposite side out as to which you found it. (Turn it over) They get sprung and cease to seal. Then you turn them over and they are good again.



< Message edited by w8ye -- 11/19/2007 3:32:10 AM >

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Original AMA #31261

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       Post #: 36

RE: COX .049 plane engine Fuel - 11/18/2007 8:37:15 PM   
MARTINSR


 

Posts: 8
Joined: 11/18/2007
From: San Francisco Bay area, CA, USA
Status: offline 		Ahhh reed valve, it looks like I lost parts (or my older boy did when he used the plane) but I pulled the motor apart and there is no reed valve. There is a piece that looks like it should be there but there is nothing. Is there any sites anywhere with a break down of parts on this darn little guy?

Brian

(in reply to w8ye)
       Post #: 37

RE: COX .049 plane engine Fuel - 11/18/2007 9:53:08 PM   
w8ye



Posts: 16715
Joined: 12/11/2001
From: Taylortown, OH, USA
Status: online 		There's a 1/2A forum on RCUniverse here somewhere. They talk about these all the time.

This will get you started. It's at the beginning of the airplanes section.
http://www.rcuniverse.com/forum/m_3747940/tm.htm


< Message edited by w8ye -- 11/18/2007 9:55:25 PM >

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Original AMA #31261

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       Post #: 38

RE: COX .049 plane engine Fuel - 11/18/2007 10:08:25 PM   
MARTINSR


 

Posts: 8
Joined: 11/18/2007
From: San Francisco Bay area, CA, USA
Status: offline 		I jumped on to ebay and found a rebuild kit that included the reed valve. Did a "biuy it now" and it is on it's way. Next weekend maybe I'll get it in the air.

Thanks so much for your help.

Brian

(in reply to w8ye)
       Post #: 39

RE: COX .049 plane engine Fuel - 11/19/2007 3:34:23 AM   
w8ye



Posts: 16715
Joined: 12/11/2001
From: Taylortown, OH, USA
Status: online 		The reed valves last until you get a crease or tare in it or in your case - miss place it?

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Original AMA #31261

(in reply to MARTINSR)
       Post #: 40

RE: COX .049 plane engine Fuel - 11/19/2007 11:07:08 AM   
MARTINSR


 

Posts: 8
Joined: 11/18/2007
From: San Francisco Bay area, CA, USA
Status: offline