KEILKRAFT K6 RESTORATION

Here is the engine as we received it from Adrian.

Let's get it dismantled and assessed for repairs.

Oh Boy, what looked like a not so bad engine on the outside had some hidden rottenness that will need to be removed in order to bring this old English gentleman back to a state of good health and running order.

 

Apart from a good clean the main issue that needs resolving is the obvious broken piston and a seriously flogged out rod and gudgeon pin, which has left the liner not to bad but definitely needing some love.

First step is to clean everything up and prepare the good parts to be reassembled once the replacement parts have been manufactured.

OK so having cleaned and measured all the other main parts we've found further issues.

Unfortunately the crankshaft is badly worn on both the main journal and the big end which has a 0.1 taper towards the back of the engine worn into it so the rod is going to always want to rub against the rear face of the case if this is left untreated.

Sooo a new crankshaft will now have to be manufactured and so we will take the opportunity to make it as a 1 piece unit with slightly altered flywheel layout.

We decided to start with dismantling the original piston assembly and manufacturing a new con rod and piston.

Here's the new piston blank all ready for final machining to size. We have replaced the riveted together multi piece setup in favour of the much more user friendly pressed in gudgeon pin set up.

 

All our replacement conrods feature a lube hole in both the top and bottom bearing to ensure good lubrication and long life.

Here is the cylinder liner all cleaned and rebored ,lapped and ready for the new piston assembly to be final fitted and reassembled onto the rest of the engine.

Now it's onto final machining the new piston to size and fitting it up to the reconditioned cylinder liner.

Out with the old and in with the nice new piston/rod assembly.

Ready to go back on to the rest of the engine.

And here's the cylinder assembly all finished and complete with the intake assembly all ready for refitting to the rest of the engine once the new crankshaft is finished.

Now we'll carry on with the new crankshaft and reassemble the engine for test running.

Here's the first stage of the new crankshaft.

Next step is machine in the big end journal, counter balance, then center drill the lube hole.

And all finished ready to refit to the engine.

Here's the front housing all reassembled with the new crank and a replacement spinner nut, the old ne was just not good enough and the thread was somewhat less than ideal.

New piston and rod now fitted to the cleaned crankcase and front housing assembly, new gasket for the front housing was also made when assembled.

And ready now to reassemble for test running, Almost!!

Well that's always a good sign, they went together easily and play nicely with each other, good.

All that remains is to fabricate a new exhaust muffler and we're all set to turn some fuel into noise and smoke. YAY!!!

Well, after a somewhat tediously long time and no small amount of effort and the odd bit of blood mixed with a goodly amount of sweat it's finally finished, phew. As the original part was made from steel, we decided it was best to follow suit and make our one from steel as well.

And ta dahh, already for the application of some fuel and spark............

Now it's off to the test stand to make him breath some fire.

 

Well after a bit of faffing about we discovered some minor technical issues with our spark ignition setup so we have opted to do the initial test runs on glow fuel.

First pop run.

Hot restart test run.