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Johnny E
Newbie
Joined: 12 Nov 2007
Posts: 38
Location: Birmingham
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 Posted: Wed Apr 16, 2008 12:55 pm Post subject: Ideas for leak stopping |
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Hello all
I've been tinkering with my MSS loco and fitted the standard upgrades: meths burner, regulator, lubricator, top-up valve, high-pressure safety valve. It's taken much fiddling to get it to run.
During the tinkering I took the whole lot apart at the front because it leaked a lot. I've put it all back together (with new O rings in the steam pipe and exhaust - that's fine) but it still leaks from where the reverser block meets the frames.
Does anyone have a definitive answer regarding the sealing of this reverser/frame joint as it seems a duff piece of design to me?
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CCairns
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Joined: 24 Apr 2007
Posts: 1036
Location: Glasgow, Scotland
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| Posted: Wed Apr 16, 2008 2:54 pm Post subject: |
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Get some oil resistant gasket paper and use this between the reverser valve assembly and the chassis frames. It is the method that was used by IP Eng on their Jane, and I believe PPS used this method as well on the Janet. I've found this works much better than using heat gasket compound, that other members have posted on here, particularly if you like using plenty of steam oil like I do.
The basic problem is these chassis frames are too easy to bend, and with all the play in the wheels, piston retaining springs, loose coupling rod pins, etc. it gets bent quite easily. Another trick to slow this process down is to use a chassis spacer on the rear cylinder plate screws, which should help to keep it a bit straighter (thank spule4 for that tip, here's his photo - http://farm4.static.flickr.com/3211/2298285475_0488496fd2_b.jpg)
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tmuir
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Location: Western Australia
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Johnny E
Newbie
Joined: 12 Nov 2007
Posts: 38
Location: Birmingham
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| Posted: Thu Apr 17, 2008 12:45 pm Post subject: |
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Great minds think alike I suppose. Went looking for some gasket paper in Halfords the other day and found nothing. Plenty of liquid gasket goo which I have acquired, but reckon the paper for this join would be preferable. Will have to search out a proper old-style car parts shop.
Took the reverser off and had a go lapping the lever-face. It still pisses out steam like a good 'un. Is there a big difference between the standard MSS reverser and the PPS posh one? It is a very tempting purchase but I'm loathed to spend any more money on the bloody thing. |
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tmuir
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Joined: 01 Aug 2006
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Location: Western Australia
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| Posted: Thu Apr 17, 2008 12:51 pm Post subject: |
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I've never actually seen the posh one up close so couldn't really say so sure but besides looks and it has probably been lapped don't see how it could be that much better.
I take it the frames are flat and have no bumps causing leaks.
I must of got lucky with my Mamod as it always worked well and only got better as I added the extras to it.
I have heard of holes been drilled out of alignment that caused leaks so check everything lines up with where it should go too.
You will always get a small leak from the regulator but it should only be a tiny wiff not a stream.
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CCairns
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Joined: 24 Apr 2007
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Location: Glasgow, Scotland
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| Posted: Thu Apr 17, 2008 12:58 pm Post subject: |
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| Quote: | | Is there a big difference between the standard MSS reverser and the PPS posh one? |
In my opinion the answer is NO, if you have lapped the Mamod/MSS one. I've got one of the PPS ones fitted to my IP Jane, and whilst it has gaskets to mount it to the chassis, it still gets the odd trickle from around the actual valve. I do not think that you will get a perfect seal around these valves, particularly if you move them for operation on the Mamods & MSSs, and indeed I get the same on my Cheddar Models engine, which uses a much similar valve, but at a higher pressure.
I got the oil resistant gasket paper off ebay. If you are still having problems sourcing some, PM me your address and I'll send you 2 appropriate sized pieces for your valve (need to wait for my return from my last overseas steam train tour for a while, starting tomorrow).
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Johnny E
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Joined: 12 Nov 2007
Posts: 38
Location: Birmingham
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| Posted: Thu Apr 17, 2008 4:41 pm Post subject: |
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Thanks for that Chris. I'll let you go off on your trip and I'll contact you afterwards if I haven't thrown the thing out before then.
I am suprised to read that even the proper jobs from PPS/IP still leak a little. Nice to know that I'll never get perfection from my tinkering with the thing. I just think that there has to be a better solution to the steam supply problem than the reverser block as it is, especially if you don't need it to use to regulate steam flow. Some sort of switch to have the full steam supply to one port or another would be ideal.
Some head scratching required here I think. |
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CCairns
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Joined: 24 Apr 2007
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Location: Glasgow, Scotland
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| Posted: Thu Apr 17, 2008 7:24 pm Post subject: |
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It is an incredible small leak, and it is only noticeable when I run steam oil around the reverser valve. Because the pistons actually rotate you'll find that there is a small leak from the cylinder plates as well, but again lapping and use of steam oil reduces that to a trickle as well. And the standard seal around the steam chest nut on a Mamod can leak very slightly, again only visible by a slight bubbling of steam oil around this nut. I think the 'O' ring that MSS use here is better at sealing, but does not stand up to the heat generated by a meths burner or gas burner as well as the old fibre washer. I was given some graphite based gasket sheet which makes a great seal for those nuts.
Of course in a standard Mamod/MSS we are using this valve to control the steam supply as well (regulator), but you have the rear mounted regulator fitted. Have you tried adjusting the position of the reverser valve to see if that makes any difference? On my IP Jane I leave the valve in the fully open position, but on a heavily modified Mamod I use about 1/2 open, as the regulator on that one is not fine enough and it is still easy to get runaway speeds with the reverser set fully open.
The only true way to stop all these leaks is to have fixed cylinders with reversing valve gear, but of course that then puts the Mamod/MSS out of the toy market, due to complexity and increased cost.
You just need to have a lot of patience some times. I've got an SL1K that I've nicknamed as the Troublesome SL1K, which originally came with replacement steel wheels, water top-up valve, uprated safety valve & gas burner, but it has barely managed to get around my test loop. It is what we refer to in the aviation world as a 'Xmas tree', which means it gets robbed for parts to keep others going. But I'm getting closer to having all the required parts to get in steaming again properly. It does back up the theory I've read elsewhere on the internet that the SL1K was not one of Mamod's best products, suffering from poor quality control during the various new owner takeovers.
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Titan
Full member
Joined: 19 Jul 2006
Posts: 638
Location: Derby
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| Posted: Thu Apr 17, 2008 8:15 pm Post subject: |
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| CCairns wrote: |
The only true way to stop all these leaks is to have fixed cylinders with reversing valve gear, but of course that then puts the Mamod/MSS out of the toy market, due to complexity and increased cost.
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Have we forgotton the Mamod William? OK I know it is slip eccentric but even so...
Anyway, I still have a few minor leaks to sort out on Titan, and although I have made my own gaskets in the past, I always find it a bit tricky punching the holes - I have an idea on how to solve this, and hopefully I will get a chance to try it out soon but I have a number of other jobs to do first!
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Les Marsh
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Joined: 03 Nov 2007
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Location: Bournemouth, Dorset.
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CCairns
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Joined: 24 Apr 2007
Posts: 1036
Location: Glasgow, Scotland
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| Posted: Thu Apr 17, 2008 8:40 pm Post subject: |
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| Quote: | | Have we forgotton the Mamod William? |
No I have not, but that valve gear only works in the direction you've asked it to move, by moving the wheels in the desired direction first, and of course the tolerances are not good enough on those valve rods that they do leak some steam as well. I also wonder what effect the unpiped exhaust steam has on the gas burner whilst running forward (an exhaust pipe blowing out the back of the reverser valve was enough to put out 2 wicks on my 3 wick burner recently).
That Flexoid gasket paper is the stuff I'm using, and to make the gasket for the regulator/reverser valve I cut a piece just slightly bigger than the valve all round, place it over the side of the valve and use an expanding circular needle file to punch the holes in the right places, and then adjust to size. Works great in the 2 locos I've done so far.
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Titan
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Joined: 19 Jul 2006
Posts: 638
Location: Derby
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| Posted: Thu Apr 17, 2008 9:09 pm Post subject: |
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| CCairns wrote: | | Quote: | | Have we forgotton the Mamod William? |
No I have not, but that valve gear only works in the direction you've asked it to move, by moving the wheels in the desired direction first, and of course the tolerances are not good enough on those valve rods that they do leak some steam as well. I also wonder what effect the unpiped exhaust steam has on the gas burner whilst running forward (an exhaust pipe blowing out the back of the reverser valve was enough to put out 2 wicks on my 3 wick burner recently). |
True enough.
However the exhaust steam does not have any effect on the burner. What it will have some effect on is the track, as any oil carried over will get dripped straight on to the rails!
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DLR
Junior Member
Joined: 13 Nov 2007
Posts: 359
Location: Blyth
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| Posted: Fri Apr 18, 2008 10:14 pm Post subject: |
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The only way i stopped the leak was to use it. Sorry i cant be more help  |
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Johnny E
Newbie
Joined: 12 Nov 2007
Posts: 38
Location: Birmingham
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| Posted: Sat Apr 19, 2008 6:27 pm Post subject: |
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Latest update on the loco. We had a small exhibition locally this morning and thought it the perfect oportunity to test how the thing is working after all the tinkering.
Oiled it. Filled the boiler and the lubricator. Lit the burner. Waited a bit. Safety valve lifted. Opened the regulator and off it went. Lovely! Went round the first corner of the loop no problem. Got half way round the second corner when the rear left wheel fell off, tipped the whole train over and was engulfed in a ball of flame, setting the wooden floor on fire.
After a rapid bit of extinguishing, I was shocked to see the wheel had simply dropped off. Shouldn't have been suprised really as I've read of many occasions of this happening before on this forum. Bloody annoying though and I was unable to run the train the rest of the day. Luckily I had my TE1a and Wilesco D9 to entertain folk. I will try re-stamping it before buying new wheels to see if that does the trick.
Why should you have to replace everything on an MSS engine before you can reliably use it? With a regulator, reverser, cylinders, safety valve, meths burner and steel wheels you've doubled cost of the loco before adding a high pressure boiler. Just go and get a Janet and be done with it. |
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pauly
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Joined: 11 Apr 2008
Posts: 1399
Location: middlesbrough
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| Posted: Sat Apr 19, 2008 7:06 pm Post subject: |
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hope my mamod isnt going to be this bad 
good luck getting yours going 
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