New .020 Muffler Kit #2620 - It seems a shame to open the packaging!? - RC ideas for the .020 Pee Wee

For fun here is a sound check with my .020 muffler in idle mode using a GMark .030 carb.

Thanks Balogh and 1/2A Nut.

Hi Balogh.
Budapest is where my wife, my daughter and myself would have visited this year had it not been for Covid-19. We planed 10 days of canoeing, hiking museum visits and lots of beer and food! Next year with luck!?

I was hoping to find the #281 exhaust throttle for the Pee Wee but had no luck. I thought that I might be able to use the muffler for a similar effect by putting a small hole in the peripheral spring!? I have been experimenting with home made exhaust throttles on the .049. I don't have any machine tools so it's done with hacksaws, files and a Dremel. I throw nothing away and found an old Husqvarna 65L oil tank plug and two 10 thou. shims. After some dermal work, hacksawing and filing I made this test unit. The flange will enable me to drill holes so that the ports align. The bottom shim is opened out to the cylinder thread size. (Some loss of compression, SPI opening and transfer opening) The upper shim to the cylinder OD and it is kinked to act as a friction device.






Your point about tightening the cylinder is very true! I shall have to make a tool to work on the OD of the fins. I made a tool for the glow head as I think the Cox tool is a bit thin!



Hi 1/2A Nut.

The top image is obviously your conversion, is the second image yours as well? If so, very nice. Where do I find a GMark 030 carb? I was thinking of utilising a .049 R/C throttle and adapting it to the Pee Wee tank backplate. I am trying to find a spare back plate right now.

Hi Daligh, too bad you could not make it to Budapest this year...

Regarding the PeeWee muffler, that design is not made for an efficient  rpm control in a measurable range. It does not seal so well even if the ring completely closes the opening on the housing. You will see castor oozing everywhere from it indicating the lack of seal, whereas you need very good seal between the mating surfaces for a good throttle control.

About your 049 exhaust throttle made of the Husquarna aluminum (?) plug, it will work well if the cylinder outer dia is just a bit smaller than that of the throttle, otherwise it will not choke the exhaust flow well.. Chances are the aluminum throttle ring will expand more than the steel cylinder and the fit between them loosening when the engine is hot.
You also need to make sure the throttle sleeve cannot move too much up and down. Not just to keep the openings aligned. The lowermost cylinder fin tends to break free at its root if the throttle vibrates during engine run..have a few cylinders with that fin dangling free on the cylinder. So your upper shim kinked a bit to keep the throttle lightly  pushed against the lowermost fin seems to be a good idea unless the friction is excessive and the servo is overloaded.

This type of throttle is sold by COX International abd Exmodelengines:

https://coxengines.ca/throttle-ring-for-cox-049-engine.html

http://www.exmodelengines.com/product.php?productid=17629&cat=267&page=1

I am also not quite well equipped with tools but this can sometimes make our hobby even more fun!

Yes the other pic I took, shows my conversion approach.
You have to buy an old G Mark .030 and rob the carb.

Balogh.
Thanks once again.

The work on the .049 engine is just experimental to try ideas that might work on a .020. As you point out, I could purchase an exhaust throttle for the .049, but I can't find the same design (#281) for the .020.

Regarding the aluminium test throttle:
The fit is close and leakage probably no more than the Cox unit. I hope to reduce differential expansion of steel/aluminium parts by leaving the threads on to help keep the aluminium cool. The kinked shim helps with vibration and keeps the throttle tight up to the lower fin. I believe that the friction is not too high! A phosphor bronze shim top and bottom might help reduce friction!?

If I could find a #281 throttle I would not be doing this!

1/2A Nut.

Great idea finding a GMark .030 but I think that might be more 'Hen's Teeth' like than finding a #281!? Plus your superb modification look like they require machine tools to make a perfect job of the conversion.

My .020 Pee Wee has arrived form the UK at last. I believe it's a 1959 model from the 1059 on the instruction sheet!?

There are some interesting prices on the sheet!

Thanks Daligh,

as the COX cylinders evolved, first thin wall cylinders with a small flange at cylinder bottom were made. Later productions with a new machinery brought about the stepped wall, and finally the thick wall cylinders. The latter 2 will fit the exhaust throttle, but the first will not, because either the small flange will not allow a single-piece exhaust throttle to slip on the cylinder, or, if the throttle ring is big enough and slips over the flange, then it will be too loose to throttle.

You may want to check your PeeWee cylinder if it has thin wall and the bottom flange, that will not match the throttle ring even if you are lucky to find one on ebay..

Daligh,

the Instruction sheet shows a Litho mark 4-62 meaning print version is  April 62 which dates  your engine back to 1962 or later..I see the cylinder is probably the thin wall with the flange at the bottom...these were made in the early days at the old, Quonset Hut facilities at Poinsettia in Santa Ana..I visited the place 2 years ago:

balogh wrote:Daligh,

the Instruction sheet shows a Litho mark 4-62 meaning print version is  April 62 which dates  your engine back to 1962 or later..I see the cylinder is probably the thin wall with the flange at the bottom...

You really are good at this!
I now know about 'Litho Marks'! Yes it's flanged, but a #281 Kit includes cylinder and piston as well as the throttle so one lives in hope but again I believe it might well be another 'Hen's Teeth' rarity!?

I am afraid the 281 set only includes the cylinder, piston and rod, at least this is what I read from the parts list in your post above....these throttle rings were sold separately as far as I know..

Select Hobbies

Yes, Steve of Selecthobbies sold them with thick wall cylinders. I thought you meant the COX factory part list where the cylinder/piston combo has the same or similar (a bit blurred on your photo) parts number.

Some folks here made the ring for the thin wall cylinders with the flange at the bottom too, with the ring split into 2 halves and the clip ring holding the halves together, I am not sure if that seals as well as it is required for an efficient throttle.

As I read it and, comparing prices, #281 is a full kit.

Thanks for mentioning the split throttle cylinder. I had already thought about this option. I have a lot of different size steel tubes in my barn, that I have collected over the years. Some are from small gas struts and may suit! Trouble is that they will be metric and the Cox will be Imperial sizes. Having said that I put my Imperial micrometer (my first apprentice tool 1966 before the UK sensibly converted to metric in 1968) and it measures .386"(.980mm)! What a weird imperial size but perfect if I can find a 10mm bore tube!

Balogh.

Just spotted your photo of Poinsettia and thanks for posting it. I guess you edited it in as I missed it before. You must be an uber Cox fan to go all that way!?

So I found a length of 10mm bore tube from a gas strut. It has a 1.5mm wall and so is 13mm OD. I found a few 12mm circlips as well.
So. I shall cut two lengths so as to make a tight fitting pair. I shall then cut a groove .5mm deep by making a jig to rotate the piece under a Dremel cutting wheel.

Well Bernie.

You need to sort your website and eBay listings because when I searched for .020 parts a month ago, that did not show up! LOL



Mind you with postage and Irish import duties it would probably cost as much.
Anyways up. I shall be ordering a lot of bits from Cox.ca in the near future so I want an uber super deal!

Bernie.

What about having some more #281s made? It would save me a lot of time making a replica!

.

Daligh wrote:Well Bernie.

You need to sort your website and eBay listings because when I searched for .020 parts a month ago, that did not show up! LOL



Mind you with postage and Irish import duties it would probably cost as much.
Anyways up. I shall be ordering a lot of bits from Cox.ca in the near future so I want an uber super deal!

Not sure what happened there. Either they were already sold by then (and I lost track of time lol) or they were not listed yet… can't remember.

International postage is a flat $9.95 no matter how big or small the order (exceptions for the three large / heavy items we stock) and there should be no VAT / Duties as we only declare CA$ 15 per package

Cox part # 281 is the complete cylinder / piston / throttle ring set for a Pee Wee RC. We have never manufactured any and it is highly unlikely that we ever will. We sometimes have the throttle rings for sale:

https://coxengines.ca/cox-.020-pee-wee-rc-throttle-ring.html    but they are extremely slow sellers, as they requite a "ground" cylinder.

We sometimes get some #281 sets:

https://coxengines.ca/cox-.020-pw-rc-cylinder-piston.html    but, contrary to popular belief, they are not that great sellers either.

Over the past 10 years or so, when we get some in, the selling rate is about 5-6 in the first few days (pent up demand) and then about one per week on average.

We had previously looked into making 020 cylinder and pistons and, if we had 250 sets made (theoretical 5 year supply), retail cost, at a 100% mark-up, would be in the $50 range. At that price, they would presumably be even slower sellers. If we had 1,000 units made, retail pricing would in the $35 range. However, there is little appetite to have a 15-20 year stock at hand.

Thank you for all of the information Bernie. I now understand a lot more regarding the exhaust throttles and cylinders.

Had this been 55 years ago, when I was a student apprentice at Laycock Engineering in Sheffield, I would have had no problem in making all of the modifications. Laycocks produced some of the highest quality precision engineered automotive components in the world. We shaved all of our spur gears, and diamond honed the bores. So. Our tool room would have made me uber accurate parts. I would have paid the machinist with a few pints of beer in our social club!

Interesting about you postal charges and import duty, tax, etc. I should have realised as I bought a second hand oil pump for my Husky chain saw from a guy in Vancouver and I paid no extras. Stuff from the US can end up costing 100% more due to tax and duty. Shall I order from your website or your eBay site? What discount can you give me for a super cheap deal? 20% per $c 100?

Well. I opened the muffler packaging as I believe that I will pursue inlet throttling. Exhaust throttling, to my mind, is somewhat counterintuitive to normal engine control methodology! Inlet mixture control is, I believe, the way to go. Having said that I shall still experiment in making an exhaust throttle for the Pee Wee.

Now. My .020 Pee Wee has the early stepped cylinder and I think that the muffler is for a parallel cylinder OD!
The alloy body fits perfectly on to the crankcase, but the upper plate will not pass over the step at the bottom of the cylinder!
Some measurements:
Bore of upper plate = .425" (10.8mm)
OD of cylinder step = .437" (11.1mm)
Od of bottom fin = .463" (11.8mm)

It was very difficult to strip the engine! After 58 years the joints were solid. So. I removed the tank and sprayed all over with easing oil and left it for 24 hours. I made a spanner for the glow head and held the crankcase in wooden vice jaws to remove the head. I then warmed the cylinder/crankcase with a heat gun and turned the cylinder with a piece of leather and pipe grips.

Looks like I'll have ease the upper plate bore by 13 thou.

Whether you order from Canada or the USA should have no bearing on what customs will collect in your country. The only thing that counts is the de minimis of the respective country and what the seller(s) declare on the CN22 form. For the UK, de minimis is the equivalent of 22 Euros and, as long as the sellers declare less, there should be no VAT unless, of course, customs sees someone trying to pass off a $1,000 laptop for $20. In the case of Cox parts, it would be very challenging for customs to come up with values. We ship to the UK every day and have never heard of any issues re VAT.

You can shop either in our eBay or online store but you may find our online store easier to navigate and there are no annoying advertisements either.

We generally do not offer any discounts unless it is for clearance items, larger orders (like $1,000+) or large quantities of the same part(s).

Cox International wrote:Whether you order from Canada or the USA should have no bearing on what customs will collect in your country. The only thing that counts is the de minimis of the respective country and what the seller(s) declare on the CN22 form. For the UK, de minimis is the equivalent of 22 Euros and, as long as the sellers declare less, there should be no VAT unless, of course, customs sees someone trying to pass off a $1,000 laptop for $20. In the case of Cox parts, it would be very challenging for customs to come up with values. We ship to the UK every day and have never heard of any issues re VAT.

You can shop either in our eBay or online store but you may find our online store easier to navigate and there are no annoying advertisements either.

We generally do not offer any discounts unless it is for clearance items, larger orders (like $1,000+) or large quantities of the same part(s).

Bernie. I live in Ireland (Eire) not the UK. Our tax and import duty is completely different to the UK.
We pay massive tax on such things as cars (automobiles) to such an extent that our imported cars are 30% more expensive than those in the UK. Having said that, since the idiots in the UK have opted out of the Euro Zone (they were never part of it really as they still used the £ not the €) they will probably end up paying 'loads o' money' for European built cars!?

So. I shall order from your website and let you know what happens.

Yes, I understand that but Ireland is in the EU and the de minimis for all European countries is 22 Euros for VAT purposes and, for Ireland, 150 Euros for duty purposes; meaning that any shipments declared under those values should, in theory at least, not incur any additional costs. We only declare CA$ 15 per package (10 Euros) and our postage costs are "hidden".