Recent content by Peter Twissell

It didn't take long for this thread to arrive at an office topic confrontation...

All good advice above, but most of all, feel free to ask questions! There is a wealth of experience among the members of this group and that should be your most useful resource as you build your first engines. What do you have access to in the way of machine tools and measuring insruments?

I had assumed that the term 'undercut' was being used to describe the gap between the teeth. Certainly, if one is considering the tooth form, it could be described as 'undercut', but then a square spline is similarly 'undercut'. I can see how this may have lead Nikhil to question whether the...

Am I missing something? I don't see how it would be possible to generate an undercut in a single pass with a rotating cutter. If the tips of the cutter were shaped to form the undercut, they would remove material from the flanks of the gear, leaving no undercut and an incorrect form. I can see...

I make copper gaskets from domestic plumbing pipe. Cut the required length, slit along the length with a hacksaw, flatten out and re-anneal.

Certainly the combustion in the cylinders is the source of the excitation, but I do not agree that the firing order is the primary source of gross engine vibration, which is what most of us will first think of when discussuing engine vibration. I have owned a number of Triumph twin cylinder...

When aligning the cylinder faces to the crankshaft, most important is that the faces are parallel to the crank axis. Small errors in the position of the cylinder bores, both along and across the crank axis will not be a problem in terms of the piston / rod / crankshaft geometry. Nice work - I do...

The twin crank engine described could be very well balanced. The pistons rise and fall together, but the cranks rotate in opposite directions, so the pistons and rods could be fully balanced by counterweights, while the secondary vibrations of the counterweights would balance one another. The...

With enough levers, it is possible to control any number of valves with a single cam lobe. Using a single cam for both inlet and exhaust does limit the design to equal inlet and exhaust duration.

Hi Bob, look in the files section, among others, there is a sub section titled errata. Cheers, Pete.

When designing a part in 3D cad, I try to approach it in the same way that it will be machined. I start by modelling the billet, then add features in the same way that they will be machined, e.g. a main bore relative to an end face, concentric features, fixing holes and finally non critical...

Definitely join the group https://groups.io/g/WittleV8 One of the first parts to make is the crankcase. The original drawing is incomplete and there are files on the group which show the missing dimensions.

I built this engine last year. Modifying the plugs was a lot more straightforward than I imagined it might be. At this scale, seating the valves directly in the heads is not a problem. The forces are very small and the biggest issue with heat is keeping it in, rather than moving it away. I did...

The BSA Bantam started life as the German DKW. After ww2, the design was given to BSA. This may go some way to explaining the mixture of threads. I have a Bantam, a D1 model from 1951. There are no metric threads on it. The engine uses Whitworth plus a few specials, while the cycle parts use...

I have made copper manifolds by plating on to 3D printed formers. They are approximately 0.8mm thick and fitted to my flat twin sidevalve engine, which will be fitted to a flying model. My design has the manifolds well protected from damage.