Almost there...

dougrail · Post by **dougrail** » Thu Dec 13, 2012 12:55 am

Got an oscillator, with a good reverser and MSS cylinders, not been used in 9 months. Fired it up, built up a ton of steam, seemed a little stiff. I tap the rods, move the wheels a bit and wham, for a couple minutes it turns and starts running like a sewing machine.

Then it stops but just as much steam is being produced. But now it's building up or leaking out as the cyls/wheels have stopped moving.

Any ideas? Have lapped the cyl surfaces, am hoping that this 1-2 minutes breakthrough is the end in sight of a rebuild but would like decent running.

Spule 4 · Post by **Spule 4** » Thu Dec 13, 2012 2:48 am

Bind in the running gear, loose wrist pin, poor lubrication...just for starters.

Sir Clothem Cap · Post by **Sir Clothem Cap** » Thu Dec 13, 2012 7:32 pm

Could you do a video as it may come to light on film

dougrail · Post by **dougrail** » Thu Dec 13, 2012 8:41 pm

Got film on my smartphone, am going to upload it tonight for perusal chap.

dougrail · Post by **dougrail** » Thu Dec 13, 2012 11:23 pm

Hi gents,

Last night's steaming. I managed to snap about a minute of the 3-4mins worth of free steaming it produced....

artfull dodger · Post by **artfull dodger** » Fri Dec 14, 2012 1:34 am

Does it have a lubricator? I am betting adding one of the dead leg or displacement type lubricators would help things. If it steams ok at first then gets stiff. I would call that thermal expansion in the cylinders causing them to start binding after they get good and hot. Lack of a proper lubricator is one major item on the old Mamod engines. Mamod's method of using the wet steam to lubricate the cylindes is not conductive to long cylinder life at all. Engine looks great otherwise. Mike

DLRdan · Post by **DLRdan** » Fri Dec 14, 2012 2:57 pm

I would guess during the papping process you've managed to get some brass in the cylinders, is there any scoring on the piston rod?

dougrail · Post by **dougrail** » Fri Dec 14, 2012 3:10 pm

That I can check when I get home. Now you mention the piston rod though...

You can swivel the piston 360 inside the cylinder. When I do it 180 and turn it about as it were, it becomes very stiff and awkward but when I set it back it rolls sweet as a nut.

Let's say some brass 'dust' has got in, how would one remove/flush it out?

Sir Clothem Cap · Post by **Sir Clothem Cap** » Fri Dec 14, 2012 6:55 pm

The quick cure is another set of pistons from dreamsteam. Your pistons have got worn into their grooves and trying to rub down the bits within could produce steam leaking through the greater gaps.

its worth persuing to make her run well whichever route you choose.

Lner fan Sam · Post by **Lner fan Sam** » Fri Dec 14, 2012 9:02 pm

Have you checked weather the dead leg lubricator is working correctly Doug? I have heard that they are a bit of a "hit and miss" with their style of operation. I hear that you can get ones that work and ones that simply don't. perhaps its feeding oil to the cylinders for the 3 to 4 minutes and then simply stops pumping the oil to the cylinders during the course of the run.

Looking at the footage it seems to stop rather abruptly instead of slowing down gradually which makes me agree with Dan's suggestion that there is something in those cylinders.

just how old are those cylinders Doug?

Sam

Spule 4 · Post by **Spule 4** » Fri Dec 14, 2012 9:21 pm

Sam the LNER man has a point.

Try the priming method Chris C. has suggested if you have not already if the issue was not binding.

dougrail · Post by **dougrail** » Fri Dec 14, 2012 9:55 pm

No scoring on the pistons gents. The cyls worked very well Feb this year and there is no scoring. I'm going to take it for a trip and film it on a better camera. Then report back.

Sir Clothem Cap · Post by **Sir Clothem Cap** » Fri Dec 14, 2012 11:10 pm

ahh I had symptoms like that on one of mine, I think one of your wheels is loose on the axle causing it to go out of time when it moves.

to test hold both wheels on one axle and push in oppersite directions if theres movement thats the problem

Chris Cairns · Post by **Chris Cairns** » Sat Dec 15, 2012 12:34 am

Doug,

I have been through your Topic on the other Forum (sorry but I no longer post on there) and you have already had some sound advice from Greg (Narrow Minded) and Peter (Superbiker_uk).

Your video shows that there is no exhaust going up the chimney and it is being pushed out from behind the cylinders, so you are losing a lot of steam from the cylinders indicating there is a blockage somewhere.

You have already been advised to check the wheel quartering (this controls the port timing) and reported back they are OK. Have you fitted new gaskets to the cylinders? Take a look back at my MSS Kit Build Topic where I cover checking the gaskets against the cylinder back plate and chassis steam/exhaust holes and adjusting where necessary - http://gardenrails.myfreeforum.org/about6201.html

You have also recently fitted a dead leg lubricator. Did it come with instructions as it sounds like you are filling it up too much. You fill it up to about 3mm below the top, thus allowing the steam that enters to cool down and the water then displaces the oil. Dream Steam tell you to prime the pipe when fitting the lubricator, but I have found you need to prime the steam line every time you fill the lubricator - I use a syringe to force some oil down the pipe, which works on all 4 dead leg lubricators that I have fitted to my locos (1 Mike Chaney, 2 IP Eng & 1 Dream Steam). The other problem with the dead leg lubricator is the T piece fitting can foul the Reverser pivot bolt, and this leads to a steam leak at the back of the reverser valve. Looking at Peter's photo of the underside of 'Ronald' his T piece appears to be touching the pivot bolt. I file that side down a bit so that the T piece fits into the reverser block at 90 degrees. To check that steam is actually making it into the lubricator leave the cap off then open the regulator to ensure steam is coming out the small pipe.

You say that one of your cylinders is stiff when you rotate the piston rod by 180 degrees. Would this be the right cylinder? 2 ways to free up that stiffness, as I had that on my MSS Kit Build and have experienced it with a couple of old Mamod SLs as well.

1. Remove the cylinder from the back plate. Put some lubricating oil into the cylinder. If you do not have a fine syringe needle then put a drop or two of oil over one cylinder port and move the piston away from this port to suck the oil into the cylinder. Repeat for the other port. Then work the piston in and out and rotate by 180 degrees as well until it frees up. This sorted my stiff MSS cylinder in the Kit Build and as my video proves it ran OK from the first steaming.

2. You need to disassemble the cylinder.

To do this you need to rest the saddle part of the cylinder on a hard surface (I use the jaw of a micro vice), push the piston in fully then tap the end of the piston gently to pop out the opposite end cap. Rotate the cylinder, pull the piston fully out, then using a suitable round drift or similar inside the cylinder tap the piston to pop out the other end cap. You can now polish up the piston and cylinder internal face with brasso or similar. Make sure you flush all the polish out then oil up the piston and see if it is now free enough. If not then use some very fine wet and dry sandpaper with some oil and gently smooth the piston face. Check regularly to see if you have removed enough as this process is not reversible. To assemble the end caps are tight push fit so I use a suitable size box spanner which fits onto the end cap with the piston rod and tap the end caps together on a hard flat surface.

Chris Cairns.

dougrail · Post by **dougrail** » Sat Dec 15, 2012 2:12 pm

Hi Chris,

Your expert and esteemed advice is warmly appreciated. I must admit that I had reservations about tampering with the internals of these cylinders as getting the caps back on seems a simple enough op, I'm uncertain of their steamtightness - as wit the laws of magic, once something incredibly hard has been done, it's then much easier to do it again.

I popped off the end caps and then poked a Brasso-soaked rag tightly down the cylinders, wiping them around. I then brought the piston head up, twirling it and with each turn it got easier.

I then gently and fine-paper sanded the pistons. I then got a dry rag and tightly inside the cylinder, used it to wipe out the Brasso + tarnish.

Now they run much freer, wihichever way the piston is turned.

Going to try a steam this afternoon!!

Spule 4 · Post by **Spule 4** » Sat Dec 15, 2012 5:58 pm

Like everything else Mamod, plus ca change....

Anyhow. When I decided to mix and match the SLK, Upgrade and SL3 cylinders and mounting ports, I found out that the upgrade kits, while the the end caps were tight fits for the SLK cylinders, were loose (as in, fall right out) of the SL3 cylinders.

A flick of torch and a splash of low temp solder and all is well now.

dougrail · Post by **dougrail** » Sat Dec 15, 2012 6:18 pm

Steam failed.

Boiler would produce steam, wheels would twitch as if they wanted to go. When reverser was pointed into direction, steam would go up the exhaust as if working, but no movement.

Have checked lubricator - oil being sucked down, no blockages in t-junction, oil or steam pipes of it.

My current lubricator has a much longer 'steam tail' than most - from the thick tub where the oil pipe and steamfeet meet, there's a smaller pipe which feeds into the rev block. Most are small which means the wider bit has to rub against trunions - central or cyl ones. Mine is long enough that it's set back away from them.

No trunions being poked there.

Cylinders are steam tight - pumping air when pushed.

There was steam coming from the front though, I think the rotary valve 'solder sandwich' may be something. Have swapped this around. Loco is now steamtight - stiff to move when in neutral, movable when in gear.

Anything else? I'm following each step here and it's getting to me.

Spule 4 · Post by **Spule 4** » Sat Dec 15, 2012 7:31 pm

One thing I don't think I have seen in your posts: does the chassis run on air?

I ran both JanMod and Major Hitchcock after each rebuild/re-assembly on compressed air for several minutes to make sure any and all binds were taken care of (and there were some). Note that the normal lubricators will not work so you have to feed a machine oil into the air line (just like an air tool) while doing the air-run.

Once I do this, I am more confident that the chassis is 100% and if there is a problem under steam, it is a boiler performance issue.

dougrail · Post by **dougrail** » Sat Dec 15, 2012 7:41 pm

Sadly I have no air testing facilities but if I had one, by God I'd use it..!!

I don't find any binds when I move the set by moving the piston...

And with that, I'm going to get ready, check for binds to be sure, and then go out into the cold for a third try. 3rd-t luk-E??

Chris Cairns · Post by **Chris Cairns** » Sat Dec 15, 2012 7:55 pm

Doug,

I think you need to be methodical about what you have done with this loco to help track down the problem easier.

So back in Feb it ran great with the MSS cylinders, a reverser valve and wheels. Loco dismantled for painting, etc.

Loco re-assembled with same cylinders, reverser valve & wheels. Video proved that steam was getting to cylinders but was then escaping around the back plates and not going up exhaust. So either port timing is out or there is a blockage in the steam path.

You told us the wheel quartering is OK so port timing should be correct. The rotary valve 'solder sandwich' is a red herring from SteamPig as it previously worked OK and it is unlikely the solder paste would break down unless you have been using a soldering iron or soldering torch on it. You have removed the cylinders to free up the pistons. These have been refitted and this time when you open the reverser valve the steam goes straight up the exhaust. So there is still a problem with the steam path.

It does sound to me that your wheel quartering has gone (there was a case of MSS wheels falling off their axle shortly after first running a loco - search somewhere on the other Forum by a member Chris and his 2nd MSS Saddle Tank loco). Otherwise your reverser valve is not lining up with the steam holes in the chassis properly, or you have damaged the cylinder back plate gaskets, which form the steam path from the chassis holes to the cylinder back plate holes, and the return exhaust steam path.

The only other change I can see you have made since Feb is fitting the dead leg lubricator. You have reported that all the pipework is OK and the oil is flowing. What type of steam oil are you using? I use 460 steam oil in all my steam engines which seems to work OK, although I suspect my William II would run better on a thinner oil.

Have you made any other changes to the mechanics of this loco since Feb that you have not previously reported?

Be careful with frustration as you can lose concentration and end up breaking something. I speak from previous experience.

Chris Cairns.

Edit: Found the MSS wheel failure Topic here from Page 7 - http://modelsteam.myfreeforum.org/ftopi ... asc-90.php

Garden Railway Forum

Almost there...

Almost there...

Who is online