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Old 01-26-2010, 10:12 PM
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AMB
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A few months back I was given a couple of cox engines, there they sat. With the current rebirth of well made classic engines "ollies" and PAW
hanging in there it seems the little cox gets overlooked, it is always in the half A site, The fact is millons were made over the years, there are tons of them around, their total production numbers exceed all the others put together OS, ST,TT Fox , Kand B and the rest
Parts are available from many sources for the cox's
Davis of course has heads, reeds, and the killer crank, the latter he has sold lots and pretty sure many just went into glow cox's
My point with some time freeing up its time to mess with my Baby bee..I did get a killer crank, diesel head, the little fuel tubing, teflon discs
They are sort of a orphan out here in diesel land run well and overall well made and CHEAP, a crank and head (Davis 40 bucks) .
Will get it going and should be able to do the U tube thing No not giving up on my little LETMO 06, and PAWS 03. Just want to try my hand at cox.
My last one was 25 years ago from the toy store bought c/l ready to go $20 or $25?? (glow) my son flew in the street in front of the house

martin

There have been many comments on the teflon disk thing pro and con, I am pro on this one better to blow the disc than the engine
sort of a safety valve



Old 01-26-2010, 10:59 PM
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Default RE: cox

Martin, do you have the gold one, and keep us posted on how a couple of them run. Thanks, Dave
Old 01-26-2010, 11:15 PM
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Default RE: cox

Dave I have 2 natural case one has a gold tank, both now have davis heads the natural case and tank has lots compression on flipping the gold tank one seems low ( about half the the other needs a replacement piston and cylinder and missing one of the screws holding the tank one
(need one), but again gift horses no complaints, the killer crank is in the good (higher compresion one)
also has the spring starter martin
Old 01-27-2010, 07:10 AM
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Default RE: cox

For you history buffs, wikipedia has a great write up on cox going back , it starts in 1945, worth a look. yes they had an RC version which was limited in production , for the Diesel puffs looks like Davis with his conversion wins in this one,MECOA sort of dabbles with his
a head too, 049, 051, but really think Davis rules here, It would be nice to see it come back made in the USA. But with current economic
conditions, electric inroads , it would be a tough undertaking. The china made stuff is nowhere near cox quality martin
Old 01-27-2010, 01:03 PM
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Default RE: cox


Sure Martin, Why not? My dieselized Cox has the RJL head, no killer crank,
and it's run fine for ages. It is an Old Golden Bee.

Tony G
Old 01-27-2010, 04:02 PM
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Default RE: cox

Tony good point, they (Cox) make fine conversions. Im quite sure that Davis has sold 1000s of these conversions, the killer crank however is good insurance if maybe a little heavy handed on adjusts, and as stated makes a fine engine even better diesel or glow. You are careful
and know what you are doing with the wee ones. they are not forgiving on overcompression and flooding as the larger ones
martin
Old 02-02-2010, 06:14 PM
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Default RE: cox

About 30 years ago there was a test in a local magazine of different conversion heads for the cox .049. There was one swedish made one with a more traditional counter piston fitted inside a modified stock head, an a comparison was made with the DD heads with a teflon disk.

If I remember correctly the verdict was that the DD heads with the large area of the disk were much harder to tune, i.e. it takes very little adjustment on the screw to go from a too low to a too high compression setting. Once set too high the disk would burn up and they could only get about one run out of each disk.

The traditional style with a smaller area of the counter piston will have a much broader range in the set screw where it runs and these were therefore much easier to tune. Also there is no disk to burn up...

Old 02-03-2010, 01:20 AM
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Default RE: cox

I think it's a Ford Vs Chev argument, let's be thankful we have a choice! DDD or RJL ... take your choice as YOU prefer!

I like my RJL head on my old Royal .40 FSR. Looks "neat" with it's blue anodising and proper tommy bar. That said, I like my DDD heads too!
Old 02-03-2010, 02:32 AM
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Default RE: cox

Yes, my post was intended as anecdotal rather than criticism. DDD has certainly shown that they know what they are doing...

I just find it a bit interesting/funny that 30 years later we are still having the same issues. I'll see if I can't find that article again, just for fun.
Old 02-03-2010, 07:44 AM
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Default RE: cox

Xenalook is offering ready made Cox conversions with DDD material.

http://coxengines.ca/product.php?pro...&cat=16&page=2
Old 02-03-2010, 10:17 AM
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Default RE: cox

It's not surprising really. There has been very little development of model diesels, due to little demand.

BTW, the RJL contra is virtually the same diameter as the bore. The thread for the contra screw of the RJL is 0.5mm pitch or ~50.8 tpi, while the Davis is 40 tpi.
Old 02-04-2010, 05:20 AM
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Default RE: cox


ORIGINAL: gkamysz

It's not surprising really. There has been very little development of model diesels, due to little demand.
Well the "little demand" part is mostly (*) true in the US, but elsewhere model diesel development has mirrored that of the model glow engine.


(*) True except for the magnificant US made Nelson 15 Diesel range of motors.


Ray
Old 02-05-2010, 06:29 AM
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Default RE: cox

Can you give me a few examples of all new designs outside of F2C? Cyclon and Fora have about one each. The Parra is the only other I can think of. The Enya offerings have been around for quite a while now.
Old 02-07-2010, 03:16 PM
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Default RE: cox

Well I managed to find the article I was talking about (it is from 1980) and just though I would post it here for those who might be interested.
A regular cox head was reworked to act as a clamp for a button style head with a small diameter (5.5 mm) regular type of counter piston (no o-ring, high silicon content material).

The advantage was said to be better heat regulation (metal rather than plastic), and thus better running and more accurate tuning with the fine thread screw and small counter piston diameter.

Regarding diesel engines there are a few of us who are still doing it and I think they're probably as "frequent" as the cox or other other small glow engines, i.e. almost non-existing. I think the older generation though are a bit bored by all the electric stuff while the next generation are completely lost to lipos, foam and ARF.


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