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91
Vehicles & Models / Re: Pennsylvania A3 Switcher (Kozo)
« Last post by Prowler901 on March 26, 2024, 02:37:33 AM »
Excellent work!  Better that that copper tube was a little too long, rather than too short. :)

Todd
92
I have been checking the dimensions of the valve and eccentric travels and also the total length for the eccentric rod and the couplings.. this works out at 1.822"   so something to work to .... I have also re-tapped the bottom of the valve rod to 8BA and used the spring that preloads the die as the rod is stainless steel that is quite tough to thread ...

Willy
93
Vehicles & Models / Re: Pennsylvania A3 Switcher (Kozo)
« Last post by cnr6400 on March 26, 2024, 12:35:02 AM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn: Looking great Kim! If anyone ever asks about the S bend, just tell them it helps keep the Reynolds number of the steam flow where it needs to be.... :Lol:  :thinking:  :atcomputer:
94
Vehicles & Models / Re: Pennsylvania A3 Switcher (Kozo)
« Last post by crueby on March 25, 2024, 10:21:26 PM »
The S is for Switcher!   :popcorn:
95
Vehicles & Models / Re: Pennsylvania A3 Switcher (Kozo)
« Last post by Admiral_dk on March 25, 2024, 10:05:18 PM »
It all adds up - both to the functionallity and the Caracter off the Loco, Kim.

You will alway reconize it as yours (and so will we) ;D

Still a great result off all your work and effort  :ThumbsUp:

Per   :cheers:
96
Your Own Design / Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Last post by Admiral_dk on March 25, 2024, 09:58:10 PM »
Every single one of my Fourstroke Motorcycles has had this kind of Oilpump - and they work really well  :)  :ThumbsUp:

Only one exception - do not under any circumstance let it rotate too slowly if you need it to deliver Pressure for bearings  :zap:  On most of mine, the lovest allowable RPM is 1150 - according to the Service Manuals ....

Great to see another chapter, Mike  :Love:

Per   :cheers:
97
Chatterbox / Re: Singer
« Last post by Admiral_dk on March 25, 2024, 09:44:10 PM »
Both amazing plus kind of horrified (love to see them still use for their original purpose - have one myself) ....

Per    :cheers:

ps  Mike - I hope you don't end up as 'Aqualunge' (the slang meaning of the word on the album)  ;)
98
Vehicles & Models / Re: Pennsylvania A3 Switcher (Kozo)
« Last post by Kim on March 25, 2024, 09:28:09 PM »
Chapter 31.2 – Plug and Nut

Next Kozo has you make the plug for attaching the water gauge to the boiler. Also, the union nut for attaching the top end of the water gauge to the manifold.  This seems a bit out of order since you can’t finish soldering parts on the water gauge till the nut is made.  On the other hand, you can’t really get the proper length of the copper tube till you can mount the water gauge on the boiler.  So maybe it is in the right order.  That Kozo... he's one smart cookie!

The plug was turned from 3/8” hex brass stock.  The center hole for the steam is 3/32”.  Of course, that hole doesn’t go all the way through, only up past the threads so it intersects a TBD(To Be Drilled) cross hole.


After parting off the plug, I moved to the mill where I proceeded to drill said cross hole. I was going to do it with the 3/32” end mill but I’d mounted the plug just a bit too far in the collet, and the edge of the mill hit the angled face of the column just a little before I got all the way through the plug.  So I finished the hole off with a 3/32” drill bit.


With the plug in hand, now I connect the water gauge to the boiler and see about how long the copper tube to the manifold needs to be.  I did a little bending, then marked it and then cut the copper tube at that length.  Figured I could do the fine-tuning on the bending after the nut and nipple were mounted.


Well, I didn’t show making the nut and nipple, but I did.  It was exactly the same as I did for the whistle, so I didn’t repeat it here.  With those parts made, I slipped the nut on the copper tube (carefully noting the orientation!) then soldered the nipple to the end of the tube.


After clean up, I remounted the sight glass to the boiler and fine-tuned the tube so that it would connect with the manifold AND keep the sight glass vertical.  You’ll note that apparently, I wasn’t very good at estimating the length of the copper tube. I had to put a bit of an S-curve in it to get things to match up properly.  Ah well.  It ought to work just fine with that extra character.  :embarassed:


Next, I’ll be making the gland nuts for mounting the glass tube.
Thanks for looking in!
Kim
99
Your Own Design / Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Last post by Vixen on March 25, 2024, 09:27:17 PM »
External Oil Scavenge Pump

Back in the 1930's, Mercedes had a strange fascination for designing multiple pumps, of all descriptions, into their Silver Arrows race cars. In the dry sump of the W165, there is a battery of 6 oil pumps (see post #191) to provide fresh oil for the crankshaft and big-end roller bearings, a second pressure pump to feed the four overhead camshafts and several scavenge pumps to scavenge (suck away) the used oil and return it to the external oil tank via the oil filter and oil cooler. There was a scavenge pump for the front of the dry sump, a second scavenge pump for the rear of the dry sump, another to remove the used oil from the camshaft bearings and a fourth one to drain the rear (clutch end) crankshaft bearing.

In addition to the 6 oil pumps, inside the dry sump, there is another scavenge pump for the supercharger bearings, a large capacity fuel pump and the main coolant water pump, all mounted externally at the front of the engine. And, if you like, you can add the two stage supercharger as two more huge air pumps. No expense (or complexity) was spared in extracting the maximum output from their engines.

 This cross section shows the layout of the pumps and superchargers at the front of the engine. I built the water coolant pump (lower left) earlier, now it is the turn of the scavenge pump for the supercharger (lower right). This will be followed by the large fuel pump, driven by the scavenge pump shaft (extreme, lower right), in due course




The oil supply for the two supercharger compressors is supplied, at low pressure, via the internal drillings from the large oil filter located to the right of the compressors. The four supercharger rotors rotate at 1.25 times crankshaft speed and therefore reach 10,000 RPM. The oil level in the supercharge rotor bearings needs to be carefully controlled; just sufficient to wet the roller bearings but no more. If you look again at the cross section drawing, you will see horizontal drillings in the supercharger housing which set the bearing oil levels(shown in black). These drilling are connected to the external scavenge pump by mess of external flexible pipework.

The supercharger scavenge pump takes the form of an internal gear pump i.e the two interlocking gears of different sizes with one rotating inside the other. Apparently this internal gear pump arrangement is particularly good at providing suction, particularly at high air to oil ratios.

In my "come in handy, one day" box were two oil pumps from some 50cc Honda Cub engines. They had been patiently waiting their turn for more than twenty years. The Honda internal gear pump parts are an ideal size for my needs, with a little modification. The two hardened steel gears, both rotate within the cast aluminium housing. The suction and delivery ports for the pump are cast into the housing.






My first task was to remove all the excess Honda material, leaving only the working core of the pump to be incorporated into the Mercedes scavenge pump.






The parts from the two pumps were temporarily stored in two separate plastic bags to avoid mixing the sets.

More to follow; so stay tuned

Mike
100
Chatterbox / Re: After a material suggestion!
« Last post by Jasonb on March 25, 2024, 08:41:45 PM »
At that thickness it would probably heat right through quite quickly and not need a long soak, you could even the heating out by laying it on a try of sand and heating from below. Whatever the modern equivalent to a tobacco tin lid is will do.
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