MSS Saddle Tank Update

CCairns · MSS Saddle Tank Update

You may recall my previous postings on this troublesome loco, where I was suffering from a serious priming problem which was leading to dangerously low boiler water levels and lead to my first melted sight 'glass'.

The route of the problem was linked to the shortness of the steam pipe that was soldered on the top of the boiler pipe, and fitted inside a much smaller steam dome nut. Unfortunately my request for the size of the standard MSS Steam dome has remained unanswered - http://modelsteam.myfreeforum.org/about6902.html

This project had stalled as the first supply of 6BA screws that I got were in fact not 6BA but something slightly smaller, so when my second supply of 6BA screws arrived today, I got my hand drill out and removed some more rivets from this loco.

Having removed the MSS boiler I fitted a standard Mamod boiler which I had refurbished, including soldering in 6BA screws on the backplate to allow easy removal of the sight 'glass'.

I've just steamed this up and after a little priming at the beginning, it went around very well on my test loop, and there was still plenty of water left in the boiler after the meths ran out. A result!

Unfortunately the standard Mamod steam dome nut is too big for the Saddle Tank as supplied, and will need some bigger spacers and screws to stop bending the running plate. Hopefully you can see this in this photo (screws are a loose fitting holding the saddle tank down).

After shoe-horning the rather tight circlip holding on the false steam chest I found that this is too small inside to completely hid the water top-up valve, and the hole in the bodywork is not lined up with the rear boiler outlet so you need to bend the bodywork backwards to fit the water top-up valve, and then by lifting the bodywork up onto the lip of the valve the cab is square again.

So to cover up this water valve with the false steam chest the bodywork across the boiler will need to be raised and the hole enlarged rearwards.

Then I tried fitting an uprated safety valve. The hex shaped part of its' body is taller than the water valve so will only fit with the bodywork pushed backwards.

However the false steam chest will fit on top of this valve with a very small clearance, so would probably be blown upwards when blowing off steam.

So it is possible to upgrade this loco like other Mamod/MSS locos but requires either a replacement boiler or a second boiler insert fitted to the supplied boiler (we have yet to have someone post on this forum that they have done this successfully yet I believe to a loco boiler), and some modifications to the bodywork.

So I'm going to leave the loco as per the first photo, probably fit some washers to the spacers for the saddle tank, and continue with this loco's running in process. Later I'll try to modify the bodywork across the boiler to allow the false steam chest to hid the water top-up valve.

What would look really nice now is a black tender behind this loco. Anyone want to swap my green MSS tender for a black MSS tender?

If MSS are reading this could you change your production of this loco by adjusting the rear bodywork to allow us to fit a water top-up valve or uprated safety valve, and just put a blanking bolt in the second boiler insert instead of soldering it up with some sort of metal insert. Thank you.

Minor1PJG

Phew a lot of work there

Glad to hear she's running now, even if heavily modified from original.

MSS do need to take note

Mamodman123

MTA aside has anyone else had even a reasonable MSS loco?

Glad you got it going but its not for the loco modding people out there...

steamyjim

Well done Chris!

Aye MM mines a good un

bessytractor

well done

am I right in assuming that hoop thing is soldered to a safety valve?

Will the uprated safety valve fit in that space?

Mamodman123

CCairns

bessytractor Yes it is a loop which has been badly soldered onto a standard safety valve, which of course has to be removed on the standard Saddle Tank loco in order to fill the boiler. Mine was so badly soldered that the safety valve leaked. I needed to clean up the solder around the face of the valve and fit a new 'O' ring. An uprated safety valve would fit in the front boiler insert, but you would need a long thin box spanner to tighten it up, as removing/replacing the saddle tank is very awkward (look closely at my scratched smokebox)

steamyjim But was it a guid one before you fitted a regulator, uprated safety valve, displacement lubricator and meths burner? And it is Gauge 1, although that should have little effect on running quality compared to Gauge O.

steamyjim

Yup thats the one Chris

Mamodman123

steamyjim

Never tried it before. It was bought to cater for the needs of the WLR

Graham-Jilly

Our MSS QEII runs great from the Box but the second one was second hand and badly assembled from a kit and would have never run . it runs great now after modifications
this is the mss QEII running sorry to steel your thread Chris

Mamodman123

CCairns

Great video Graham-Jilly. Just as well I checked through my posting as the warning system that highlights a new posting did not work for this thread, at least for me.

Is that MSS solid fuel fired or Meths fired?

I liked your 'Guard' although a little out of gauge!

Still looking at getting a sidetank MSS if I can for a reasonable price.

Graham-Jilly

Chris it was meths fired as i dont like the mamod supplied tablets as they were ineficient and round and wouldnt fit in the burner . breaking them to fit made a mess so opted for meths burner.
love the smell of burning meths

tmuir · Re: MSS Saddle Tank Update

CCairns

tmuir Thanks Tony, that would convert to just over 45/64ths of an inch, so it is the same size as the Mamod Steam Dome nut ( http://modelsteam.myfreeforum.org/about6902.html ).

Graham-Jilly Graham, Mamod no longer make the rectangular shaped tablets so you need to buy the MSS ones, which break in half and fit the burner tray. However they stink like hell. I've got about 3 boxes worth from boxed locos and a set I 've got on ebay recently, and burn these in my stationary engines at present. However once they have got damp they can be very explosive. MSS supply them in one of those little clear zip bags which should help a little with keeping out the damp.

I've finally got the steam pipe out of this boiler (solder refused to melt under my gas solder torch) and confirmed that it was too short to fit right up into the small steam dome nut. I'm going to try and drill out the metal they have put into the second boiler insert, and if successful will have a normal Mamod/MSS boiler again. Otherwise I'll need to get a new boiler insert and fit that. Then with a longer steam pipe I hope this boiler/short steam nut combination will actually work properly with none of that priming again. Will keep you advised of my progress.

Graham-Jilly

two of my engines have had ip contol valves fited so i have sealed that part of the boiler as its no longer needed

MSS Saddle Tank Update

Re: MSS Saddle Tank Update