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RE: Cox Reed Valve FAQ - 1/22/2006 8:21:35 AM   
KidEpoxy



Posts: 3265
Joined: 10/14/2004
From: San Antonio, TX, USA
Status: offline 		Just what is the thread on the SureStart prop screw.. they didn't do something silly like use a standard thread like 8-32 did they?

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RE: Cox Reed Valve FAQ - 1/22/2006 5:53:01 PM   
BMatthews



Posts: 8895
Joined: 10/4/2002
From: Burnaby, BC, CANADA
Status: offline
quote:

ORIGINAL: KidEpoxy

Just what is the thread on the SureStart prop screw.. they didn't do something silly like use a standard thread like 8-32 did they?


Good question-

All the 049's use the same prop screw size. It's a 5-40. Some are longer than the others to suit the little spinners or just basic screws but they are all 5-40 thread. They apparently picked this odd size because it works out that a 5-40 is a lovely fit into a 1/8 hole.

Unfortunetly this is an odd size these days for many. The best bet is to locate an industrial screw supplier and order up a box of 100 in 3/4 and 1 inch sizes and then divide the order between a few local modellers. The 1 inch is for use with the TeeDee and Black Widow style spinner cones. Doing a quick google I find that 5-40 is not common out there either. But the following online folks have them as of this posting date...

www.boltdepot.com - in allen cap style only. box of 100 for 3/4 is $5.85 and 1 inch is $19 .
www.fastener-express.com has the same allen cap sizes at about the same prices but only sells the longer size in lots of 10 for $2.84.
http://www.swapmeetdave.com/MachineScrews.htm has 7 boxes of 5-40 x 1 1/2 long cheap round heads that are a bit rusty but come with some nuts available for 0.50 each. (obviously shipping will be more than that)
www.grainger.com has standard round head screws. 3/4 - $3.63 and 1 inch - $8.04


< Message edited by BMatthews -- 1/22/2006 6:00:04 PM >


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RE: Cox Reed Valve FAQ - 1/24/2006 3:09:40 AM   
burtcs


 

Posts: 456
Joined: 12/20/2004
From: Corvallis, OR, USA
Status: offline 		Bruce et al: While poking around on the "Everything Diesel forum" I noticed someone inquired about Cox diesel conversions. This has been beat to death here but a very useful list of Cox parts emerged. I am shamelessly encluding the URL here. Well worth a look if you've ever wondered what a #9 cylinder came out of. Use the printer friendly version for a print out - hey I got mine 8).


http://www.clstunt.com/htdocs/dcforum/DCForumID1/17842.html

HTH - Steve B.



(in reply to BMatthews)
       Post #: 28

RE: Cox Reed Valve FAQ - 1/24/2006 4:02:15 AM   
Silvaire


 

Posts: 277
Joined: 9/9/2003
From: Napa, CA, USA
Status: offline 		Another EXCELLENT source for hardware is McMaster Carr. http://www.mcmaster.com/

Of course they have 5-40 screws. In 3/4" length, they list 20 DIFFERENT items. (This includes various combinations of steel, stainless, brass, round heads, flat heads, socket heads, slotted, phillips, etc., etc.)

Prices are good too. For example: round head plated steel 3/4" 5-40 screws are $3.79 per 100, and stainless steel socket head 1" 5-40 screws are $10.44 per 50. If you want a stock looking screw but in stainless for use with a TD style spinner, the 1" round head screws are $9.83 per hundred.

I have had excellent service from this company, even when dealing with a problem on their part. Their selection is just short of unbelievable. To them, 5-40 threaded hardware is common stuff. While browsing their online catalog, I happened to see that they even carry 5/40 allthread (take your choice of brass, stainless, plated steel or plain steel). This is just another example of their substantial variety of hardware.

Arlen

< Message edited by Silvaire -- 1/24/2006 10:55:32 PM >

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RE: Cox Reed Valve FAQ - 1/30/2006 9:16:43 PM   
calmat


 

Posts: 22
Joined: 4/24/2005
From: st louis, MO, USA
Status: offline 		Maybe this has been answered before but i want to know why some cox o49 engines have two large exhaust ports and some have 4 small slits. How does performance differ if it does.

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       Post #: 30

RE: Cox Reed Valve FAQ - 1/30/2006 9:35:05 PM   
magic612



Posts: 14
Joined: 1/16/2006
From: Somewhere south of Chicago, IL, USA
Status: offline
quote:

ORIGINAL: BMatthews

But the following online folks have them as of this posting date...

www.boltdepot.com - in allen cap style only. box of 100 for 3/4 is $5.85 and 1 inch is $19 .
www.fastener-express.com has the same allen cap sizes at about the same prices but only sells the longer size in lots of 10 for $2.84.
http://www.swapmeetdave.com/MachineScrews.htm has 7 boxes of 5-40 x 1 1/2 long cheap round heads that are a bit rusty but come with some nuts available for 0.50 each. (obviously shipping will be more than that)
www.grainger.com has standard round head screws. 3/4 - $3.63 and 1 inch - $8.04



Try The Nutty Company too - I used to live near them. They have all kinds of standard and odd sizes (including those 5-40's!)

http://www.nutty.com/

3/4" length - $5.40 / 100
1" length - $6.30 / 100

Lots of other lengths available, too.

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       Post #: 31

RE: Cox Reed Valve FAQ - 2/3/2006 12:53:08 PM   
mclintock



Posts: 1090
Joined: 2/5/2004
From: Brighton, MA, USA
Status: offline 		This link I swiped from the rcg version of this forum, but it's too good not to pass everywhere.

Castor oil- why? Well now you know:
http://modelenginenews.org/faq/index.html#qa5

Short answer, because instead of burning off during a lean run, it actually thickens in high temps, where synth would just burn off, leaving the metal bare when it needs it most! It's easier to clean off castor varnish than to put metal back on.

I put this here 'cause cox engines are more likely to be running with no throttle than a norvel, where if lean one could just throttle down and land.


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RE: Cox Reed Valve FAQ - 2/3/2006 3:19:03 PM   
gcb



Posts: 2385
Joined: 10/24/2002
From: Port Ewen, NY, USA
Status: offline
quote:

ORIGINAL: mclintock
Short answer, because instead of burning off during a lean run, it actually thickens in high temps, where synth would just burn off, leaving the metal bare when it needs it most! It's easier to clean off castor varnish than to put metal back on.


Long version:
This is especially true of an iron piston/steel cylinder combo because as temperature rises, the fits get tighter, which causes even more heat until you get "thermal runaway" which can ruin an engine. Castor turning to varnish would cause the engine to slow down to some degree which lessens the extreme heat production. Most synthetics flash off at this point and allow the engine to wear out with metal to metal contact.

ABC engines provide for the cylinder to expand more than the piston which prevents thermal runaway. If the lube reaches its flash point more than normal wear will occur but usually not to such a large degree.

BTW, iron/steel setups allow a varnish buildup in the pores of the iron piston which will compensate for a lot of engine wear. If your engine is showing less compression, sometimes switching to all-castor fuel will buy you some compression as it runs. ABC does not do this because of the high silicon pistons.
Conversely, if your iron/steel engine has a lot of time on it and you switch from all-castor to part synthetic, you may find that your engine is worn out. Switching back to all-castor can restore at least some of the varnish seal.
quote:


I put this here 'cause cox engines are more likely to be running with no throttle than a norvel, where if lean one could just throttle down and land.


One of the hottest parts of an engine is the top of the piston. In a Cox engine, directly under that hot spot is the ball socket. With over lean runs and all-synthetic lube you run the chance of the lube flashing off and leaving the ball socket unlubed. For this reason, fuel for Cox engines should contain some Castor oil.

In the other direction, when Cox fuel was all Castor we had to tear the engines down occasionally to remove varnish if we ran them hard. Some synthetic in the fuel prevents or lessens varnishing.

There are some synthetics that are touted to be just as good as Castor. Unfortunately, not all fuels use these types.

Bottom Line: Your engine, your choice.

Sorry if this seems like a lot of rambling. I've never met an engine I didn't like.

George

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RE: Cox Reed Valve FAQ - 2/3/2006 3:34:05 PM   
mclintock



Posts: 1090
Joined: 2/5/2004
From: Brighton, MA, USA
Status: offline 		Does that Norvel NVX 1/2a fuel need to have castor added? I have some of that, and after running an engine in the house, I noticed the taste in my mouth whilst breathing the smoke was different than the fuel I was running that I knew had castor, since I added it..

I bought the nvx for the express reason that I thought i'd not have to add castor, so I'd know what the percentage of nitro was.


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RE: Cox Reed Valve FAQ - 2/3/2006 6:20:20 PM   
Andrew


 

Posts: 1904
Joined: 2/4/2003
From: Murray, KY,
Status: offline 		As Patrick said, KLOTZ is a lubricant company, not a product. When Wildcat Fuels out of Nicholasville, KY was mixing NORVELs NVX fuel, the oil content was a mixture of KLOTZ Techniplate and BeNOL. Techniplate (there are several blends) is one of KLOTZ's synthetic series lubes. BeNOL is their racing castor lube. I have no idea what oils are in the SIG NVX fuel or what the synthetic/castor ratio might be.

The tech sheets for KLOTZ are here. BeNOL (all castor) is BC-175. Original Techniplate is KL-200, ModeLube Techniplate is KL-310 and Super Techniplate is KL-100. Super Techniplate is an 80/20 synthetic/castor blend.

When looking at the tech sheets, notice the burn rating (how much carbon buildup), the film strength (how "sticky" the lube is) and the flash point. Castor has the highest flash point and doesn't burn out leaving you high and dry.

In addition the points George made concerning castor, since it does not burn easily, it is expelled as a liquid and carries a great amount of heat with it. When the other oils flash off, they contribute to heat buildup and high heat transfer is lost.

I use BeNOL as my castor additive if the commercial fuel has a low castor content.

< Message edited by Andrew -- 2/3/2006 6:22:32 PM >

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RE: Cox Reed Valve FAQ - 3/13/2006 4:27:45 AM   
KidEpoxy



Posts: 3265
Joined: 10/14/2004
From: San Antonio, TX, USA
Status: offline 		How bad of a person am I if I don't use the fabled "Piston Reset Tool" on a new SureStart... I'd hate to have to spend $20 to get a tool for a $7 engine. I'm not looking to make an UberScreamer, just fly around on 15%nitro

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RE: Cox Reed Valve FAQ - 3/13/2006 6:17:33 AM   
combatpigg



Posts: 9593
Joined: 11/22/2003
From: arlington, WA, USA
Status: offline 		A loose ball socket will cause erratic runs and eventually allow the engine to hammer itself to death, instead of lasting for decades, like many well kept COX engines can. The engine will never run like it could, as a smooth, tight unit. I didn't know that reset tools were $20 now! They will run with sloppy ball sockets, but the question is, for how long?

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RE: Cox Reed Valve FAQ - 3/27/2006 5:44:27 PM   
KidEpoxy



Posts: 3265
Joined: 10/14/2004
From: San Antonio, TX, USA
Status: offline 		I was just ballpark guessing the $20 tool, figured the shipping in too

What about a homemade throttle for the SureStart, something to gatevalve the choketube with a link to an arm on the needle to lean up for the low air, rich up to normal WOT? Just a stab at this, but basic concept before geometry throw ratio calcs... possibly need to use the ghosted length on the needle arm to get less needle travel for the throttle travel

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< Message edited by KidEpoxy -- 3/27/2006 5:49:40 PM >

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Optional MA is part of AMA history, we can go optional AGAIN if we just say so

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       Post #: 38