Thursday 24 May 2018

Engine in assembly

Before I started assembling the engine, I tried to make sure everything so far was able to be assembled. I am in two minds about the benefits of good daylight: you can see what you're doing, but you can see what has gone wrong with the paintwork.  On examination, I find the paintwork needs to be improved for complete coverage, and then another coat is likely to be needed to make a good presentation: I even have a better brush with which to apply a final coat. I shall need to look critically at all the details to make sure that potential dirt traps are suitably filled. The domed nuts for fixing on the sides can be seen.  The central tube of the engine has been put in place temporarily - it seems to be a good fit, but the upper fixing may need to be filed out so that the mid-way support fits the superstructure comfortably.  Although the tanks are stainless I thought they would look better with  the same finish as the rest of the car.

...and a view of the rear of the car so far.  Some paintwork is not yet finished.

Now for the newly arrived parts:  This shows the arrangement of the steams ports in the cylinder. Not shown is the work I have done to widen the central hole to 6.5 mm diameter and tapered the cylinder ends of the holes to improve the steam flow (without any experiment I don't really know how effective this work will be)


This last picture shows that I have started on re-shaping and polishing the central exhaust port to hopefully improve the outgoing steam flow.

The next task will be to fit and assemble the crank shaft and bearings - I have little experience of fitting parts which have an interference fit, so I am hoping that my efforts will be successful without needing to use too much hammer aided persuasion.  The next instalment is expected imminently, as long as FedEx don't lose it!  So I am assuming that I shall soon have the pistons and connecting parts in place, and then some more painting.  Some of the engine parts are likely to get warm, so I shall look out for some higher temperature paints for them.

Tuesday 8 May 2018

Engine Coming

FedEx lost part of my engine. The latest kit contained 2 packages; one was delivered.  They have now said that the 2nd package has been traced. The missing part was the frame - I now have the cylinder blocks and crankshaft pieces.  It is no real hardship to be delayed as I have some extra time to finish some more painting.  I am painting over any bolts which form part of the main assembly and which I do not intend to undo again.  I have gained some bumps and chips to the paintwork, so another coat will go on when the re-assembly has been done.
Thinking about the next stage. ... In principle , I believe that all steam channels should offer the least resistance to the passage of steam.  The routes should be free from any unnecessary constriction and should be smooth with no sharp edges.  An opening with sharp edges has a discharge coefficient of about 0.6, but that for a smooth opening is about 0.98.  I think that any "fitting" activities will involve smoothing sharp edges and irregularities, polishing the sides and maximising the opening area - all to reduce pressure losses.  I was surprised to see that the steam route from the port to the cylinder end comprised three drilled holes next to each other.  To reduce pressure loss along the way, I shall taper (/streamline) the ends of the holes so that they more resemble a venturi,  the holes might allow for some widening, and the holes could be smoothed, probably with a needle file.  I am not sure if there would be any undesirable side effects from combining the 3 holes into a single slot - could it reduce the strength of the cylinder, or cause distortion, or cause a stress concentration/ fatigue cracks?  I shan't be touching the steam ports as I don't want to upset any valve timings.  The GA of the engine gives an indication as to the dimensions of the valve gear - it should be possible to make a simulation.to better understand any problems with timing set-up.
The exhaust port is not centred on the exhaust pipe fitting - I shall try to reduce any irregularities by filing and smoothing. 
Pictures to come.