Mamod SE3

This a twin cylinder Mamod SE3, stationary model steam engine, made in England in the late 1960’s. It is in almost original condition. The safety valve boss has been replaced and the pistons have been replaced with CJW Steam adjustable pistons. However, we are keeping  the original pistons so that the machine can be restored more closely to its original state, if need be.

It has the later type top lever whistle but still has the lovely brass meths burner, rather than the later solid fuel type used in the the late 1970’s.


Seems there are a lot of tarted up engines out there. These look very pretty until you steam them. Then all the paint melts – or catches fire. Alternatively you find them with pin-prick holes in the boiler, often due to dezincification.

Fortunately, this beauty suffers from neither of those problems. There were, however, some minor issues:-

  1. Base was distorted and would not sit flat. May have happened in transit, may be due to uneven tightening of boiler mounting loops. May be a bit of both. Fixed by slackening mounting loops a little, gently straightening base and re-tightening evenly.
  2. The whistle and the chimney was not quite vertical. We fixed this by rotating the boiler very slightly while we was fixing the issue with the base.
  3. The pistons were different lengths. One was 3mm longer than the other! That’s why we replaced these with adjustable length pistons. These are specially made for Mamod engines by a chap in Sussex trading as CJW Steam, who specialises in these things. Seems Mamod used a variety of different piston lengths. The adjustable pistons mean one can get the length within about 100 microns of its optimum. Pretty good really.
  4. Then there was the water level plug. Don’t think we have ever seen such a mashed up example. Somebody had even forced the lugs round into a strange bull’s horns shape! Also the threads where stripped bare. Obviously we replaced this with a nice new one from Model Enthusiasts in Sussex.

We did the usual replacement of all washers. Also soaked the whistle in vinegar for half an hour or so, in order to remove any limescale and ensure that it seals properly when not in use. We also greased all the threads and washers with non-sticky silicone grease. This is amazing stuff because firstly it helps everything seal with a lot less force and secondly, it means that valve and filler plugs can be unscrewed very easily. I.e. no more having to use pliers or Mole wrenches to remove jammed filler plugs!

Finally we oiled all the moving parts, making sure that we filled the oil pots on the cylinder backplates. Then we filled the boiler and the burner, lit it, waited a few minutes, et voila!

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