Mini Engine / Mini 16v project | Last Minute Motorsport

The engine.

The last Mini I owned had a 1275 turbo from a Metro Turbo. But I always fancied a 16v head after seeing a KAD 16 head at a show. The cost put me off though, and I knew that somewhere someone had built a motorbike cylinder head onto the A-series block.

Sourcing the engine

Finding the 1275 motor was the first challenge. But again this was found locally, half buried in a shed in a field.

After finding the project shell and engine, I knew that I had to build a 16v engine. A short internet search lead me to Specialist Components website and the fairly well known BMW head conversion.

I ordered their manual and set about plans to build myself the engine I wanted.

Sourcing the head

Finding the head was simple enough on eBay. I'm always looking for a bargain so I don't want to buy the most expensive parts I can find. I know there are different cams available in the BMW head, but I was happy to settle for whatever cams I could find. To me, it's not about achieving maximum power, it's about the building process. I do things because I can.

The block

The block was stripped bare and checked over. the head steady bolt had been snapped and drilled out poorly to the next size, but apart from that, it seemed all good. I started by blanking all the holes in the block that were no longer required and sent the block off for machining.

The engine was bored out to +60" and new cam bearings fitted. New pistons and bearings were also supplied.

My original intention was to run an open block with the coolant passing through the head gasket. But eventually I changed my mind and dry decked it as so many others have.

Early attempts

I have an annoying trait that I believe that if someone else can do something, then I can learn. So I set about making the adaptor plates myself using the tools and knowledge I had.

Early attempts required a plate with holes cut with a hole cutter and adjustable plates bolted on to hold seal. This would have worked, but would not have looked fantastic.

I had to try a different route to make this better.

The world of 3D printing

For a long time, I have been able to use basic CAD packages to design what I need, but having it made was a different problem. So I went to learn how to use newer CAD packages and quickly moved from Solidworks to Fusion 360.

Having full access to these programs through work and experienced staff for guidance, I was then able to design anything I wanted. 3D printing then allows me to make these parts at low cost to try them out for fit and function. This new world of making plastic parts for trials is fantastic. All parts I make are printed and trialled before making from metal.

3D materials

Whilst most of the material used for 3D printing is PLA, different materials can be printed. PLA is cheap and easy to print which makes it ideal for templates, but it does have its drawbacks. It will start to go soft at around 50 degrees C.

There are other materials available that will take a higher temperature and withstand being in an engine bay. I may use this for brackets etc, but also possibly to make the intake manifold.

All printing is done at home so I can make parts overnight to try the next day.

Machining

Plastic parts are great and easy to make. But making them from aluminium is a different game altogether. Luckily we have the equipment in work, it just required someone to show me how to use it,

After spending some time over the summer break learning how to use the machines, aluminium plates were made to replace the plastic ones. With these fitted, time to make brackets etc.