Author Topic: Rare Cox piston. (Read 3353 times)

Clancy Arnold · « **on:** July 18, 2009, 05:12:16 PM »

Full story posted in Open Forum.

Found a rare Cox piston in my 1/2 A parts. Two piece piston with a stamped sheet metal connecting rod retainer.

I also have somewhere a rare Cox W head.

Clancy

kenneth cook · « **Reply #1 on:** July 18, 2009, 06:26:33 PM »

Clancy, I own that particular engine myself. The connecting rod is aluminum while that steel keyhole shaped retainer is held in with a circlip. I remember these engines showing up around 1978-79. I'm not sure if they were a Cox copy, but all parts will interchange. They are truly horrible. The backplate has the worst plating on it and does peel off. The engine hardly makes the power of a poor running Babe Bee. Mine just overheats and sags within a few seconds. The cylinder has a fin spacing just slightly closer than a standard Cox cylinder. The exhaust port is slightly narrower as well. It surely makes a good conversation piece but thats about it. I just can't imagine how thin the piston skirt is after that circlip groove was cut. Ken

Robert McHam · « **Reply #2 on:** July 18, 2009, 06:29:30 PM »

Quote from: kenneth cook on July 18, 2009, 06:26:33 PM

Clancy, I own that particular engine myself. The connecting rod is aluminum while that steel keyhole shaped retainer is held in with a circlip. I remember these engines showing up around 1978-79. I'm not sure if they were a Cox copy, but all parts will interchange. They are truly horrible. The backplate has the worst plating on it and does peel off. The engine hardly makes the power of a poor running Babe Bee. Mine just overheats and sags within a few seconds. The cylinder has a fin spacing just slightly closer than a standard Cox cylinder. The exhaust port is slightly narrower as well. It surely makes a good conversation piece but thats about it. I just can't imagine how thin the piston skirt is after that circlip groove was cut. Ken

I still think it is a good find!

Robert

kenneth cook · « **Reply #3 on:** July 18, 2009, 06:34:37 PM »

I just wanted to add an additional comment that the backplate in any way has Cox or made in the USA on it. Reading your post in the Open section Larry states the W plug. The tank itself has no markings on it either. This can make dating a bit tough. It purely was an attempt to save costs in my opinion. Ken

Robert McHam · « **Reply #4 on:** July 18, 2009, 07:09:35 PM »

Seems I read somewhere that there were some overseas direct knockoffs of the Cox engines. Like the AP wasp is a cheap copy of the Norvel, they looked right but never had the precision nor quality of the originals.
Not sure if I have ever seen even a picture of the Cox clones much less the real thing.

I have read that the use of these 3 piece pistons can run much higher revs and due to the tight tolerances by Cox fit quite well. The 3 piece piston set weighs in at 3.2 grams. Not sure how the aluminum con rod holds up when used in high performance applications. Not sure I would trust it as well myself.

Robert

Jim Thomerson · « **Reply #5 on:** July 19, 2009, 01:25:35 PM »

My Spacehopper has that kind of piston. I discovered it just as you did. I replaced the piston with a modern piston and the engine runs fine. So I would guess that that kind of piston was used in Space Bugs, Jr. Space Bugs, and Thermal Hoppers as well. Maybe the present piston came in with the TD and the Baby Bee.

I haven't looked in a while, but I think Atwood and WenMac engines had a similar piston. I got a couple of small engines off eBay. Said to be wonderful, but both were junk. One was an Enya with the three piece piston which had come apart. Gene Hempel put it back together and the engine ran fine. I fixed up the other engine and put both of them back on eBay and 3x'd my money.

George · « **Reply #6 on:** July 20, 2009, 12:46:46 PM »

Quote from: Clancy Arnold on July 18, 2009, 05:12:16 PM

I also have somewhere a rare Cox W head.

Clancy

What is a "W" head?

I know the early Cox cylinders took a more narrow threaded glow head than the present one.

George

Jim Thomerson · « **Reply #7 on:** July 20, 2009, 06:34:44 PM »

W heads had the glowplug element in the shape of a W. There were several different brands for 1/2A engines. I think I have one that came off a Baby Bee bought in the 70's. I have seen K&B Allyn Sky Fury with W regular glow plug and another with a head with W element. There was some advertising hype about them.

Marvin Denny · « **Reply #8 on:** July 20, 2009, 07:41:14 PM »

Quote from: Jim Thomerson on July 20, 2009, 06:34:44 PM

W heads had the glowplug element in the shape of a W. There were several different brands for 1/2A engines. I think I have one that came off a Baby Bee bought in the 70's. I have seen K&B Allyn Sky Fury with W regular glow plug and another with a head with W element. There was some advertising hype about them.

I have a box of 12 of those Fury plugs with the "miracle W Element". all new.

Bigiron

Robert McHam · « **Reply #9 on:** July 20, 2009, 07:49:07 PM »

You have to look to make sure. I had one once myself and liked it. Not sure of any performance increase but somehow it just seemed a like a better idea for a glow plug element style. I'll post a picture I have of one next to a T.D. head but You really cannot see the element of the "W" style. Only the element of the T.D. plug is easily seem. Not my picture. You can see a difference, just not the complete W shape.

Robert

George · « **Reply #10 on:** July 21, 2009, 03:18:59 PM »

Quote from: Jim Thomerson on July 20, 2009, 06:34:44 PM

W heads had the glowplug element in the shape of a W. There were several different brands for 1/2A engines. I think I have one that came off a Baby Bee bought in the 70's. I have seen K&B Allyn Sky Fury with W regular glow plug and another with a head with W element. There was some advertising hype about them.

I remember the element in the Sky Fury plugs but I have never seen that type element in a Cox plug. Might those Cox plugs have a replaced/rebuilt element?

George

Clancy Arnold · « **Reply #11 on:** July 23, 2009, 07:00:13 AM »

George
When I asked Larry Renger about the three part piston that I had found, he mentioned the W head as another Cox engine part to collect as Cox lost a patent infringement suit over them.

Clancy

George · « **Reply #12 on:** July 23, 2009, 01:40:31 PM »

Quote from: Clancy Arnold on July 23, 2009, 07:00:13 AM

George
When I asked Larry Renger about the three part piston that I had found, he mentioned the W head as another Cox engine part to collect as Cox lost a patent infringement suit over them.

Clancy

Wow! Learn something every day. I remember the original ads for the Space Bug that showed a regular glow plug instead of glow head (art, not picture), but I had never heard of that Cox "W" element. Apparently they are VERY scarce. Any idea how many were made?

Next question, how well did they work? I think the Sky Furys worked about the same as any other plug, but it's been SO long since I used one.

George

Robert McHam · « **Reply #13 on:** July 23, 2009, 02:33:53 PM »

Quote from: George Bain on July 23, 2009, 01:40:31 PM

Wow! Learn something every day. I remember the original ads for the Space Bug that showed a regular glow plug instead of glow head (art, not picture), but I had never heard of that Cox "W" element. Apparently they are VERY scarce. Any idea how many were made?

Next question, how well did they work? I think the Sky Furys worked about the same as any other plug, but it's been SO long since I used one.

George

I'm sure a bunch were made since so many are known of. Bet there are a lot on Ebay and the sellers are not aware of it. So many don't even pull the head off. Also many were used and discarded when spent. Who knew it would be collectible?
As for performance, I never heard any of the hype till now so that did not enter into my thoughts when I used it but it ran perfectly fine on my Golden Bee. I was intrigued by the different shape to be sure and cannot for sure remember how I came by it but feel pretty sure I had bought it from the LHS as that was where almost everything I had came from there at the time. Just looking at the element, it just seemed more efficient as it had more of the element exposed rather than the coil type. Not reality , but that was my impression then. I don't recall anything being better or faster, it just felt good to know it was in there! When it failed I tried to get another and could not.

What I cannot remember is whether or not it had the "Tee Dee" knurl ring on the top. Seem lik the answer is no because it was not trumpet shaped like a Tee Dee.

Now for something a little more rare would be one of the reedie cases with the tiny hole drilled though it. bet there were fewer of those made.

Robert

Frank Sheridan · « **Reply #14 on:** July 23, 2009, 03:08:24 PM »

The Cox reed valve engine crankcases with the pre-drilled hole were intended for use with a spring loaded throttle sleeve. The straight tail end of the spring extended into the hole while the other end was anchored in the sleeve. Those cases are rare indeed.

Jim Thomerson · « **Reply #15 on:** August 03, 2009, 06:53:12 PM »

I ran across my Cox W-element head. I had put it on a product 049. It looked, somehow, a little odd, so I checked and yes it had the W-element. It fits the modern Cox cylinders so not all that old. Also have seen some high compression heads with three cooling fins rather than the usual two. Looked at them carefully. The head configuration looks right and they have the knurl ring around the glowplug post.

Robert McHam · « **Reply #16 on:** August 03, 2009, 08:28:14 PM »

I just got a grab bag of parts in the mail today. Mostly Cox but a little of Norvel.
Among these items there were a couple of high comp heads (2 fin), a hopped up Tee Dee 049 and a spring clip that looks like it might be the right size for the 3 piece piston assembly. I have no idea what I will do with it for now but will not toss it! Ya just never know!

No W element plugs

.

Robert

Larry Renger · « **Reply #17 on:** August 04, 2009, 10:55:24 AM »

The AP Wasp is indeed a copy of the Norvel, but I wouldn't call it "cheap". It has a bronze bushed crankcase, which the Norvel never did. The engines last a LONG time, and so-far, only one of my 6 wasn't quite right, as it blew fuel out the nose of the case; it ran like gangbusters, though with that loose shaft, so it could have been great for FF where fuel consumption isn't an issue. They replaced it with no argument and the new one is just fine.

Author Topic: Rare Cox piston. (Read 3353 times)

Clancy Arnold

Rare Cox piston.

kenneth cook

Re: Rare Cox piston.

Robert McHam

Re: Rare Cox piston.

kenneth cook

Re: Rare Cox piston.

Robert McHam

Re: Rare Cox piston.

Jim Thomerson

Re: Rare Cox piston.

George

Re: Rare Cox piston.

Jim Thomerson

Re: Rare Cox piston.

Marvin Denny

Re: Rare Cox piston.

Robert McHam

Re: Rare Cox piston.

George

Re: Rare Cox piston.

Clancy Arnold

Re: Rare Cox piston.

George

Re: Rare Cox piston.

Robert McHam

Re: Rare Cox piston.

Frank Sheridan

Re: Rare Cox piston.

Jim Thomerson

Re: Rare Cox piston.

Robert McHam

Re: Rare Cox piston.

Larry Renger

Re: Rare Cox piston.