MSS Side Tank Performance
Posted: Sat Apr 08, 2017 9:30 pm
Hello Everybody,
My first post here although I've been reading the forum for a long time. I'm looking for some assistance with my MSS Loco which I built from a new kit Autumn last year. The loco is entirely standard and 45mm gauge. I'm on my fourth box of MSS fuel tablets for it and performance has been variable to say the least.
Firstly - are my expectations too high?
I have an outdoor oval of level track with 4 ft radius curves. The loco will now, with some persuasion, run almost continually provided there is no load. To do so I preheat the water, fill the tank and then use one tablet to build pressure and make steam. I lubricate the cylinder and reverser faces with Accucraft steam oil and then run the loco on blocks to ensure it's all warmed up and not leaking water. The loco runs beautifully on blocks, very slow running is possible and very little in the way of leaks, just a very slight dribble from the piston ports on the cylinder. Once that fuel tablet is done after 7-8 minutes and provided it's got about 60-70% of the water left I put a new tablet in immediately and put it on the rails. It will then usually run by itself for 5-6 minutes at a reasonable speed. It will go faster but then runs out of steam.
The problem I have is it has no pulling power whatsoever. One MSS coach is enough to prevent continuous running. It will do 3 or 4 laps if I let it stand building pressure but that's that. It seems the boiler isn't replenishing the steam quickly enough, or the steam is escaping elsewhere.
So far I've:-
Drilled the frame steam ports to around 3mm as the reverser ports were slightly occluded.
Manually worked the cylinders with 3 in 1 type mineral oil for over 1 hour each to ensure smooth operation.
Lapped the cylinder and reverser faces with fine wet and dry on a perfectly flat surface
Polished the faces of the aluminium 45mm spacer blocks (they were very uneven and this was the change that allowed the loco to run continuously light engine)
Removed the whistle actuator arm (it fouled on the cab roof)
As far as I can tell I have no leaks around the sight glass, very occasionally I see some bubbles around the bottom of the safety valve but reversing the fibre washer seems to correct that. The reverser has a very very narrow band where neither forward or reverse is selected.
Would one expect a standard loco to be able to operate continuously on the fuel tablets with one or two vehicles in tow?
As the loco will not reach the safety valve release pressure unless standing still I don't think an updated safety valve will make much difference, perhaps only providing a better seal to the boiler. I've been considering a gas burner but I can't really commit to that while there's this doubt in my mind that something else is wrong with the loco.
Basically, until I'm sure the the standard loco is behaving properly I'm not keen to upgrade parts.
The only other thing to note is the distance between outer flange faces on the wheels seems slightly wider than my 1980s LGB Stainz, so that would potentially cause binding on the corners, but it doesn't seem too tight and will run freely if I test it manually with the with the cylinders removed.
Thanks for any advice you can provide.
Graeme
My first post here although I've been reading the forum for a long time. I'm looking for some assistance with my MSS Loco which I built from a new kit Autumn last year. The loco is entirely standard and 45mm gauge. I'm on my fourth box of MSS fuel tablets for it and performance has been variable to say the least.
Firstly - are my expectations too high?
I have an outdoor oval of level track with 4 ft radius curves. The loco will now, with some persuasion, run almost continually provided there is no load. To do so I preheat the water, fill the tank and then use one tablet to build pressure and make steam. I lubricate the cylinder and reverser faces with Accucraft steam oil and then run the loco on blocks to ensure it's all warmed up and not leaking water. The loco runs beautifully on blocks, very slow running is possible and very little in the way of leaks, just a very slight dribble from the piston ports on the cylinder. Once that fuel tablet is done after 7-8 minutes and provided it's got about 60-70% of the water left I put a new tablet in immediately and put it on the rails. It will then usually run by itself for 5-6 minutes at a reasonable speed. It will go faster but then runs out of steam.
The problem I have is it has no pulling power whatsoever. One MSS coach is enough to prevent continuous running. It will do 3 or 4 laps if I let it stand building pressure but that's that. It seems the boiler isn't replenishing the steam quickly enough, or the steam is escaping elsewhere.
So far I've:-
Drilled the frame steam ports to around 3mm as the reverser ports were slightly occluded.
Manually worked the cylinders with 3 in 1 type mineral oil for over 1 hour each to ensure smooth operation.
Lapped the cylinder and reverser faces with fine wet and dry on a perfectly flat surface
Polished the faces of the aluminium 45mm spacer blocks (they were very uneven and this was the change that allowed the loco to run continuously light engine)
Removed the whistle actuator arm (it fouled on the cab roof)
As far as I can tell I have no leaks around the sight glass, very occasionally I see some bubbles around the bottom of the safety valve but reversing the fibre washer seems to correct that. The reverser has a very very narrow band where neither forward or reverse is selected.
Would one expect a standard loco to be able to operate continuously on the fuel tablets with one or two vehicles in tow?
As the loco will not reach the safety valve release pressure unless standing still I don't think an updated safety valve will make much difference, perhaps only providing a better seal to the boiler. I've been considering a gas burner but I can't really commit to that while there's this doubt in my mind that something else is wrong with the loco.
Basically, until I'm sure the the standard loco is behaving properly I'm not keen to upgrade parts.
The only other thing to note is the distance between outer flange faces on the wheels seems slightly wider than my 1980s LGB Stainz, so that would potentially cause binding on the corners, but it doesn't seem too tight and will run freely if I test it manually with the with the cylinders removed.
Thanks for any advice you can provide.
Graeme