Restoration Projects

Tale of a Mamod Minor

My experience in making and repairing things has been mainly in electronics and my ability in metalwork very limited. However, I had to start somewhere.

My starting point was with an old Mamod MM2 Minor static engine that I bought in the early 1980s from a bric-a-brac market stall in Wokingham in Berkshire for the princely sum of £4-00p.

It looked sad, neglected, no burner tray, no safety valve and very dirty. I had to rescue it and knew exactly what I had bought. Unfortunately I didn't know how to get it into a fit state to steam - well not for a while anyway!

Eventually I took the bull by the horns (well engine by the steam chimney to be exact!) and very carefully took it to pieces in the same way that I did with radio sets. I cleaned everything up and checked that the boiler was perfectly serviceable without any nasty holes where there shouldn't be. I then carefully rebuilt it.

I already had a Mamod TE1a Traction Engine that I steamed occasionally and realised that the safety valve and its burner tray fitted the Minor. My next step was getting steam up and running it.

My inexperience in rebuilding was not punished. The Minor ran beautifully after being oiled, filled with hot water from the kettle and having built up a good head of steam. I was very pleased that it ran so well. Nothing to do with my abilities, more to do with the fact that this Mamod engine was (and still is) very robust and just needed some TLC!

Well that is the story of my first rebuild. There will be more. I would like to try my hand at more restoration whilst learning new metal working skills including soldering and metal cutting and bending.

Pre-1957 Mamod SE1

I was very pleased to find this engine as it is now the oldest Mamod in my collection.

My feelings on restoration so far is to keep things the way they are without re-painting. However, this little engine seems to have been repainted during its lifetime and not to the normal Mamod livery of red base plate and black firebox. I decided that a full re-paint restoration was in order. A new exhaust pipe between the cylinder block assembly and steam chimney needed to be fitted as it was missing.

Apart from doing a little restoration on a couple of Mamod MM2 Minors and other small repairs, this was my first major restoration. It was a case of working out what needed to be done, how it was to be done, then do it! A minefield for a novice like me so I had to do a lot of swotting by reading books, checking fellow modellers’ web sites and practicing on old metal scraps to learn how to do silver soldering. The following text and photos show what and how I did it.

Stripping Down the Engine

Before stripping off the old paint the following jobs needed to be done:
Soak all the nuts, bolts, screws and moving parts in WD40 to allow them to be freed up.

Remove the safety valve and ensure that it was perfectly serviceable, in this instance it was. It just needed a little cleaning and a drop of oil.

Carefully remove the piston and cylinder from the engine block assembly and crankshaft.

Disconnect the engine steam feed pipe from the boiler by unscrewing the pipe coupling on top of the boiler.

Undo the screws securing the engine block to the base plate and remove it from the base plate with the steam feed pipe still attached. This pipe did not need to be removed from the cylinder block.

Loosen the pulley grub screw and remove the pulley from the crankshaft. The crankshaft was then withdrawn from the engine block assembly.

Remove the nuts and bolts securing the boiler band to the base plate and remove the boiler, boiler band and firebox from the base plate.

Cleaning and re-painting

The next phase of the project involved cleaning all the moving parts and polishing the boiler, boiler band and steam pipe. The next job was cleaning up the cylinder (inside and out) and piston ensuring that the piston moved freely in the cylinder. The same was done for the crankshaft and pulley. To assist with removing that stubborn dirt I soaked all the parts in white vinegar. Other cleaning materials used were Brillo pads, Brasso polish and a duster.

NOTE:

Care was taken not to score the cylinder bore and piston surface.

Material needed for repainting were:

A proprietary paint stripper for metal.
Spray tin of Red heat-resistant metal paint for the base plate.
Spray tin of Black heat-resistant metal paint for the fire box.
Fine grade emery cloth.

Before proceeding with paint stripping and re-painting, I read the instructions on the containers and thought hopefully that I couldn’t go far wrong.

PAINTING TIP:

Don’t be tempted to re-spray in one coat as this will result in runs in the paint.

Several thin coats are better, allowing the paint to dry between applications. If necessary use a fine emery cloth to smooth down between coats of paint.

The base plate and firebox were the items that required repainting. The stages were as follows:

The engine block assembly was in no need of repainting, just cleaning.

Remove the old paint on the firebox and the base plate using a proprietary paint stripper for metal.

Wash off the paint stripper when it had done its job and clean up the exposed metal ensuring that it was grease free.

Spray paint the base plate in red and the firebox in black.

I allowed all re-painted items to dry thoroughly so that the paint hardened before the engine was re-assembled.

Re-assembly and Steaming Preparation

The engine was reassembled. Steaming the engine was the next step. All moving parts were oiled. Having built up a head of steam, leaks from the boiler and pipes were checked for. Any problems were then resolved.

The new exhaust pipe will be fitted when I have the pipe to finish the job. That will involve silver soldering and I have gained a lot of knowledge from Mooseman‘s excellent silver soldering video on his web site. I need to add some insulating feet as well.

The result of all this work is a very presentable old and restored static engine that I’m very proud to have in my collection.

Acknowledgements

I would like to thank all those (listed and unlisted) who have provided a great deal of information and tips (from their books and / or web sites) that have helped me in this restoration project:

Live Steam Toys - A User’s Guide by Roly Williams
Appendix C in Toyshop Steam by Basil Harley
Silver Soldering from the SteamEnthusiasts Web Site
Roly Williams Web Site
Mooseman’s Web Site

Many more web sites too numerous to list here. For some of the web sites see my Links Page.

TE1 Traction Engine

This engine comes from the 1965 to 1967 era but an exact date could not be determined (not that it really matters!). It was in a very dirty condition with some scratches on the boiler. I decided that renovation was going to be kept to a minimum as the engine was in a robust condition anyway.

Some items were missing and other parts needing replacing. The missing parts were the scuttle, fuel tray and front axle spring which I bought for the engine. The two items that needed replacing were the overflow plug and safety valve which I had among my spares.

The cleaning procedures that I used are almost identical to those I used on the old SE1 engine previously described in this section. Some dismantling was done i.e. engine piston and cylinder, flywheel as it was screwed onto the engine crank shaft, and removal of the crankshaft from its mounting on top of the boiler. Cleaning was then started and when finished everything was re-assembled. I am very pleased with the end result as shown in the second photo.