Engines > Restoration of Model Engines

Our Heinrici resto….

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Alyn Foundry:
I thought I’d share a short video of our Reeves of Birmingham Heinrici replica we finally got running recently.

I bought the model some 25 or so years ago from Jonathan ( scalemodel ) Vincent being the intermediary between us.
Knowing the Achilles heel of this model, the displacer piston, I stripped off the hot end to find a massive Brass piston and connecting rod. Having got so many “ Irons in the fire “ the model was shelved.

When Jo presented her rescued ETW prototype and then a “ rouge “ set of Aluminium castings that had been sold on eBay, it prompted us to have another peek at our engine. Just for clarity I say “ rouge “ because I had bought the patterns and sole rights to produce from the original owner. Jo’s set of castings must have been sold before this happened.

Our engine was pretty roughly built. The flywheels were a very poor fit on the crankshaft. We decided to sleeve the shafts and bore them to fit the now oversized dimensions. The sleeves were Loctited in place. One of the bearing standards had been over tightened and had cracked. We prepped the crack using a Triangular file and then used an Aluminium solder to join the broken parts together. I was really surprised by the strength of this, new to me, filler rod and it held up to being reamed out to the new size of the crankshaft.

We now turned our attention to the displacer piston and rod. This IS the problem area that most builders who follow the drawings end up with a non runner. The design is way too heavy and being made from Brass tends to conduct the heat very quickly to the cold end. The answer is quite simple, we used an empty aerosol deodorant canister. Once relieved of any further propellant you can pull out the plastic valve with a pair of pliers. We used a short length of 5 mm Brass rod and pushed it into the hole where the valve had been. Suitably roughened at the joint and a healthy glob of Epoxy resin to both hold and seal the assembly. Whilst the glue was setting we made a small PTFE bush that was a press fit into the much larger Brass bushing.

Being the impatient type that I am the new bush was slipped onto the displacer rod, pushed home through the top cover before the rod being squadged flat in the heavy duty machine vice. We could now rotate the assembly and gently adjust the piston to make it concentric with the hot end tube. With the crankshaft set at TDC we could then line up the rod with the short conrod to drill the pivot hole.

The bearing standards were then re placed on the top cover and checked for alignment. Once everything was turning smoothly we checked for leaks. It turned out that the bottom of the hot end was leaking. It had been made from Steel tube with a disc Silver soldered into it. This isn’t a very good idea at all because the direct heat will definitely melt the soldered joint. My solution was to turn up a Steel “ U “ shaped cover that came partially up the sides of the tube. After a thorough roughing of the tube the whole assembly was flooded with Silver solder, Tenacity No 5 being the flux of choice. Once cooled we checked again with the soapy water and this time no bubbles formed anywhere.

The engine had come fitted to the familiar fabricated Steel base so we refitted it and used a little camping gas stove to provide the heating. After several attempts with zero results we rigged up a small submersible water pump and put on a cooling reservoir. The engine ran almost immediately after heating.

Not the best of restoration’s but an interesting exercise non the less. I’ve attached a couple of pictures of the process.

The last photo is of the cast Iron base that I got with the original patterns all those years ago.

 :cheers:  Graham.

Alyn Foundry:
It seems I forgot to add the YouTube link but I can’t find the additional bits on the forum that AdeV was referring to.

                  #Invalid YouTube Link#[/youtube]

Ah, I think I’ve found it…..

 :cheers:  Graham.

Alyn Foundry:


Still not working ....  :killcomputer: ....

You could place the address as text just for the rest of us to Copy & Paste  ;)

Well the good news (from you) is that you got it running now  :ThumbsUp:


You have to delete the" https://youtu.be/" part and insert only the remaining code into the forum button.


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