Oil burning boiler mods

[Marty_Knox]

What diameter are you looking at? For a 1" OD tube I use SA 178, 12 or 13 gauge, but it's getting hard to find. SA 178 is a welded tube, annealed after welding - for a seamless tube the spec is SA 192.

[Vance Nickerson]

Backhead view of the Pacific. I install dry pipes on my boilers whether coal or oil firing for the turret to help with the atomizer getting as dry steam as possible. I use a high temperature rated stainless ball valve for smoke box installations. Never attach the sight glass to the turret. And yes i have seen several done that way. Im not hesitant to drill and tap the boiler shell but I always use heavy wall tubing.

[johnpenn74]

Brian,
For your Allen 4-6-0 I would recommend you put a steam rated ball valve in the dome instead of a smokebox throttle. I recently did a throttle job on Chris's 0-4-0; replaced the original LE or RSC smokebox throttle with a ball valve in an 8" boiler Smokebox. Getting it all in it was a real pain. While it is working fine now; I have had some people tell me that even a steam rated valve will not have teflon seats that will last in the hot temp of the smokebox which is my other reason to use the dome. I have two other Allen Engines with the Allen d slide type throttle valve, they both have problems from 20+ years of use, but when I replace I will replace with a simple ball valve.

[Marty_Knox]

I'll second what John said - put a ball valve in the dome.
I put a ball valve in the smokebox of an oil-burning locomotive - it failed after one day's use.

[Soot n' Cinders]

If going with a dome throttle, I've been very pleased with the arrangement I came up with. I have a globe valve with the threads on the stem removed so it operates as a push-pull valve. The valve is centered vertically between the top of the dome and where the throttle rod comes through so there is a 2:1 lever set up inside the boiler.
Servicing is easy, the valve is mounted on a flange with 4 stainless socket head cap screws so loosening those as well as unscrewing the throttle rod and pulling the upper hinge pin is all thats needed to remove the valve. The throttle rod connection is a modified square nut at the base of the doubling levers. The throttle rod is a piece of 3/16" stainless with a 10-32 thread that starts on a long taper to ease starting the thread.
One other change I made was changing the shape of the valve plug from a linear opening plug to an equal percentage plug, seen on the right.

[Fender]

Brian,
For your Allen 4-6-0 I would recommend you put a steam rated ball valve in the dome instead of a smokebox throttle. I recently did a throttle job on Chris's 0-4-0; replaced the original LE or RSC smokebox throttle with a ball valve in an 8" boiler Smokebox. Getting it all in it was a real pain. While it is working fine now; I have had some people tell me that even a steam rated valve will not have teflon seats that will last in the hot temp of the smokebox which is my other reason to use the dome. I have two other Allen Engines with the Allen d slide type throttle valve, they both have problems from 20+ years of use, but when I replace I will replace with a simple ball valve.

As it happens, John P was helping me get some piping and the old throttle valve out of the smokebox on my coal-burning mogul this week. Still haven't been able to get the valve free from its mounting, but at least it is now disconnected, and not in the way of the new valve.
I was looking at other options, and found this valve, which has a "grafoil" seat and is rated for higher temps and pressures than the more common brass/ptfe ball valves. It is a 1/4" npt lever-operated ball valve that is rated for 900 psi steam and 565F temperature.
https://www.discovervalve.com/mm5/merch ... e=1%2F4%22

I should mention that the old ball valve (brass/ptfe seals) has worked OK in the smokebox for many years, but all the copper tubing is shot, and the valves position against the front tube sheet makes it nearly impossible to maintain, so I want to put the new valve closer to the smokebox door.