Wells Engine Problems

mc_mc · Wells Engine Problems

I am going to need some advice on this one.

I recently purchased this Wells engine:

Very solidly built and fairly heavy. A copper boiler with brass cylinder and port face, mounted on a metal base in turn mounted on a wooden base. A three wick meths burner provides the power source and I noted there was no vent hole in the burner design.

When recieved the safety valve was corroded into it's thread, but some WD-40 and application of a little force sorted that out. I then discovered that the saftey valve spring had corroded into a solid mass and the shaft was stuck in it's bolt. Scraping the rust away, some more WD-40 and application of force fixed that problem too. I renewed the washers and that all seemed fine.

The cylinder itself seemed fine and everything moves freely with a bit of oil.

So I thought it was time to give it it's first run. Filled up with boiling water and lit the burner.

After a few minutes I was concerned to see steam shooting out of the exahust pipe, rotating the flywheel proved there was some force in the piston but not enough to give more than a quarter turn. Covering the exhaust pipe did seem to force steam into the cylinder, but with nowhere to now go the steam forced the cylinder piston to it's full extension and was held there.

So I've obviously got a leak between the steam pipe and exaust pipe. When cooled I confirmed this by blowing in the exaust pipe and blocking the exhaust port, this should not of let me blow any air through the pipe but instead the air came out of the steam inlet port. Blocking both ports with my finger caused blown air to come out of the safety valve hole.

I decided to run this engine on air and borrowed by Dad's tire inflator, I discovered that I had further leaks from the engine block itself. This was made by sandwiching two brass pieces together it seems and I was getting a small leak at the top of the join. There are also strange copper inserts in the port face as can be seen in these picture:

Picture showing the join between the two pieces making up the engine mounting block, the small leak comes out of the top part of the join:

This picture shows the steam pipe from the boiler and the exaust pipe:

So I think following one or both of the following might be the problem:

- The 'composite' portface assembly made of the two pieces of brass isn't joined very well and so is allowing steam to leak from one port to the other without entering the cylinder.

- The steam pipes have some how been connected together before they enter the port faces (notice the solder joint in the picture above)

I've also noticed the piston shaft is bent slightly, but I think that's a minor problem at the moment.

So how do you think I should proceed?

- Desolder the steam pipes and see if they are the problem
- Try to disassemble the port face 'sandwich'
- clean up the engine and try and sell it on!
- Any other suggestions?

I don't really want to sell it on, because I like it's chunky looks and would like to get it going really. I would also have to be honest with the buyer so that I can sleep at night.

Cranko

Thats a really nice engine you have there. I 'm not sure why they would have laminated two pieces in the first place. I think I would be inclined to make a new one from 1 piece of brass

Steve_S

I think I would unsolder the pipes and try to see what the problem is. I wouldn't try to seperate the two brass halves. It looks like they've been fixed together with copper rivets which have then been ground flat. You'd have to drill them out to seperate the halves, but you wouldn't be any further forward if you did that.

tmuir

If you need to make any new parts MC_MC let me know and I will make you copies of that part of the book so you can make new parts, I've got 2 copies of the book to make this but will be soon putting one on ebay.

Tony

8_10 Brass Cleaner

I agree that a new valve block is the way forward, however loctite make a product that is designed to fill cracks, its highly viscous and will go into cracks. It may be worth a try, I'd put it on the joint between the two pieces of brass (where you say it leaks), theoretically it will seal, as the temperature isnt very high in the great scheme of things.

The one problem is that it may not seal between the pipes, or worse still block them up. But as they say nothing ventured nothing gained.

Another simpler fix may be to unsolder the pipes from the rear of the block, remove it and carefully enlarge the holes to the outside diameter of a new bit of copper pipe. Being carefull that the centres of the holes remain in the same place. Once you have done this solder in two sections of pipe, with pipe projecting a little on the cylinder side, but a lot on the back. The soldering on the cylinder side is the important part. Once it has cooled, carefully file the copper pipes down on the cylinder side, and finally 'lap' in on a pice of very fine sandpaper layed on a glass plate.

connect up the pipework and assemble and it should them be ok.

mc_mc

Have tried to desolder the pipes from the port face block today to see if I can work out what's what.

I wasn't even able to melt the solder, I can get the whole thing very hot with my mini-blow torch but I think the large brass plate is soaking up the heat and radiating it away.

The solder seems to be a gold colour rather than the usual grey sliver colour. I'm not sure what that means.

Off to buy a bigger blow torch tomorrow.

tmuir

If its a gold colour it could brazing rather than solder which means you will have to get it very hot to melt it (read very hot as having the metal glowing)

I remember using that stuff at school.
You had little beads / blobs of brazing material, not sure exactly what it was but basically brass and something else. We had to use an oxy torch to melt the stuff.

mj

It could be as simple as a scratch on the port face, as the pic shows a small mark between the 2 ports. If the main loss of steam is caused by a gap between the brass engine frame plates. You could solder longer steam pipes that come right through to the port face & seal up the gap between the plates. Another possibility would be to solder up the port holes & then re-drill the holes (the solder should draw into the gap between the plates by capillary action if it's well fluxed).

Cranko

The gold material isproberbly easyflow or similar which has a melting point twice that of normal solder. You will have to put a lot of heat in to release this which may damage the pipes and brass block

MooseMan

Unsoldering easyflo or any other silver solder's a bugger....it'll probably be a lot easier to snip the pipes close to the block and drill out the stumps carefully.

mc_mc

Okay I finally got round to buying one of these:

I used it to blast the portface block and was tugging at it with the pliers with no success. I was just about to give up and then it actually just fell off on it's own.

Looking at it:

I think there was a definite gap in the solder between the two pipes and so it was able to leak from one to the other. The pipes weren't pushed into the block hardly at all it seems. You can now really see the golden colour of the solder so it's definitely not the usual soft stuff.

Here's what the pipes look like, they are still welded together with a large chunk of that solder. (you can also see a corresponding gap in the solder between the two pipes)

So I think I now need to separate those pipes and try and clean off that existing gold stuff from everything. Any one got any tips for that? Then I will try soft soldering just the steam pipe in to the block and see how things go from there.

CJW

Looking at the joint i would think that when it was solderd the brass wasn't hot enough and the result being the solder ran up the pipes instead.
Easist way to remove siver solder is to heat to a dull cherry red and with a piece of steel wool wipe it off.Lots of sparks and bits get stuck to the pipe.If you have some flux for silver solder mix some to the same thickness as milk and dab the wire wool in it as you use it.
One good thing about silver solder is that you can soft solder over the top.But not the other way round.
With any luck they used one of the lower temp solders Easflo etc.If they used one of the higher ones its going to be a emery cloth job

Cranko

Congratulations!! the cause of the problem has been located and appears to be an easy fix.

tmuir

Good stuff, I was worried you wouldn't be able to desolder it.
As you say its obvious were the problem was, now to just fix it.

Are you going to attempt to manufacture one like the books says or the simpler one like the one you just removed?

Graham-Jilly

Looks like it was put on with brassing rod and not silver or soft solder. I did braising in my plumbing days you needed a hell of a lot more heat to use that stuff

and special brassing flux

oldstuff

mc, did you get it fixed?

mc_mc

Yesterday I cleaned off the old solder off the block and pipes, mainly by physically grinding it away. I then resoldered just the steam pipe and did a very neat job (eventually). Unfortunately when testing it still leaked a bit, the engine almost ran but not quite

I think I'm going to carefully drill the hole in the existing block a bit deeper which should make things easier to solder as the pipe will hold in place better.

If that doesn't work I will attempt to make a new face block using the information that tmuir provided in another thread, but I haven't got any suitable material at the moment, I need a very thick piece of metal for that.

mc_mc

I finally managed to get the soldering right (third time lucky). The tricky bit was filling in the large hole between the ports so that steam didn't leak out the side of my joint. I thought I'd got it at first, reassembled then engine and gave it a try but I hadn't quite managed to seal it, steam was leaking out the side of my joint.

It was tricky not to block the steam ports holes with solder whilst trying to fill in the other hole, in the end I bunged them up with matchsticks to stop the solder flowing in. They charred a bit but it seemed to do the trick nicely and when I removed them afterwards there was a decent hole for the steam. I stopped trying to use flux as it seemed to make the solder just drip off my work piece rather than stay put and cling round the pipe, I expect the problem was that I used too much.

Here's some pictures of my repair, not the neatest job but the big blob on the left hand side was needed to fill the gap.

Here's a video of my first run this morning, I was a bit excited I'm afraid, it really rewarding when you see something actually working for the first time, I think I must of fired that engine up at least 6 times previously with no success.

Still lots of steam leaking from around the portface and the 'sandwich' joints so I do plan to make another one if I can acquire some suitable material (its finding something thick enough, I certainly don't want to make another sandwich having seen this one).

The plastic tube I installed between the boiler and port face tube was obtained from a pump action bathroom dispenser bottle, putting this in made things much easier to work with, my first attempts trying to solder everything directly to the existing boiler tube were doomed to failure I think as it was a little too short. The tube into the boiler is soldered with the same gold brazing material and so I didn't want to touch that end as it was nicely steam tight already, so cutting the pipe was the easiest option.

Thanks for all the advice everyone, it's really good to know that if you mess things up someone will know what to do.

Wallace

Well done mc.

Runs nicely, and a job well done.

Always satisfying seeing them in action again

tmuir

Success at last!

Glad you got it sorted, I remember my first restoration was a Te1a that I had to replace all the pipes on. Took me ages to get it all working but was worth it in the end.

I'm guessing the engine isn't even run in as it would of never worked from new so after a few more steamings it will probably even free up a bit and run faster.

Cranko

You Definitly should feel some sence of accomplisment now. Well done

Sandman

Perseverance pays off.

Great result mate.

Steve_S

Great stuff. It's alway rewarding when they burst into life after a struggle!

James

Well done MC! That's really great

Cranko

Wells is not an engine I have heard much about , is there a site out there someplace

SillyBilly

Nice one!

James

Cranko, nope, they were built by students in the 70s. they did a TE and this stationary.

tmuir

Cranko have a look here to see some info about how wells engines are made.
http://modelsteam.myfreeforum.org/about2927.html

Cranko

Thanks , I have heard of the school boy traction engine but didn't make the connection with the stationary

CJW

What size lump of brass were you looking for to make a new one ?we might have a piece knocking round the workshop

mc_mc

CJW

HE HE Thought it was going to be a big lump

Got loads of bits around that size.
Going steaming this afternoon,so will find some later and if i get time on monday might even be able to run it through the mill to get it perfect size.

Cranko

mc_mc

Cranko

YES YES YES Please!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

CJW

He he nice machine but cost a fortune to get delivery,then you need a nice 8/10 inch vice ,add to that a few tool holders and the accountant has a fit.

He then sue's you for stress related heart attack.