Injector Progress

Not content with getting all excited over the governor body casting, another significant milestone was been reached in the back burner department  in January. The injectors. The idea that we needed to source injectors from the dawn of time has always been somewhat daunting, given the precise nature of these components. 

Fortunately the Armley Mills archive did include a set of drawings for them, however these lacked some of the information we would have liked on materials and tolerances. The blog entry for 25th May 2019 illustrated the injectors borrowed from the MDB2 together with an illustration from the McLaren-Benz Catalogue which captures the complexity of these wee beasties, reproduced here too.

For understandable reasons, no-one from the world of 21st Century Diesels was going to make a little batch of injectors like this, however some contacts at Mercedes-Benz were very helpful with materials and tolerance advice. Paul Turner took the McLaren drawings and cadded them up. As these are Benz components being manufactured by McLaren the old drawings were already in metric which kept things nice and simple.

Eventually we found a company that are interested in manufacturing small batches of fiddly components, Grange Square Engineering. They turned our order for ten sets of bits round very quickly. 

Before and after, one of the new injectors together with a sample borrowed from the MDB2 engine.

It must be emphasised that despite appearances, these are a set of bits which require assembly by somebody who knows what they are doing to ensure that the fit and finish is right.

These are parts C and D, the needle valve body nut and the needle valve body. We have not got all the bits A to Q (no sprayer valve spring, part F for example) but is great to have money spent and a box full of bits. We don’t have to worry about making them, now the fear is getting them to work.

After getting all excited about that we are heads down and on with more drilling to prepare the cab sides for riveting.