Making the last camshaft proved the adage that “practice make perfect”. Not that I am in any way saying that the camshafts are perfect, far from it! But the last camshaft (I hope) took the least amount of time and for a change very few problems. Each time I nearly made a mistake I managed to stop myself from continuing, which is not an insignificant result believe me!

I now have a camshaft to harden as an experiment, and a completed camshaft for each Seal engine. Their production was not without incident and a little heartache at times, but I must go on record and thank Steve Huck for all his considerable help with cutting charts and giving me confidence when I had doubts, so thank you Steve.

The issue of errata on plans is something I have mentioned before. If you consider the ‘fit for purpose’ test as in the UK then the Seal plans I have would not pass. If the plans were new then an error or two may be expected, however this design by Edgar T Westbury is over 60 years old. Is it too much to expect some obvious errors to be removed from the plans SOLD to the public? Let alone some major issues over the camshaft design. I know I lost some sleep over what was right and what was wrong. One thing I hope to come out of the Seal build is a comprehensive list of ‘issues’ relating to the plans and they will be posted on my main website as well as my Blog for future builders. Additionally a copy of errata will be sent to the publishers of the plans, with a hope they amend their plans. We shall see.

The camshafts are not complete as yet, since as they have some finishing left but the machining is completed. A bi-product of completing this stage of the build is the much diminished fear factor of producing camshafts, since the 3 completed camshafts and the 50% practice camshaft (on a blank I ‘corrupted’ early on) has given me some experience.

So its now onwards and upwards, with the next major items being the two crankshafts……….ohhhhhh……..

Wednesday 4^th March 2009 – Seal engine update

I thought yesterdays brain clogging problems were over. However, whilst I managed to sort out the dimensions for the camshaft by use of graph paper, when it came to machining I was still unconvinced it was correct

I thought I would help myself by marking, in permanent marker pen, the general location of the cams, so I could see if I was going wrong somewhere. In the event these marks caused me even more difficulty! I did a dry run as it were and ran through the sequence written on my notebook. Whilst it finished where it should, the gap between cam blanks seemed too large. So I got the defective camshaft (it broke in the middle) sent by a previous owner of the castings, and when comparing the marked out bar with the camshaft the spacing was fine, but the gaps seemed to large [see photo].

In the end I was so confused I just gave up and thought I would cut the cams as per my dimensions. You may have guessed that after cutting the first two cams everything was as it should be and the cutting of the remaining blanks went without a hitch. I do not know why I got so tied up with the layout (I suspect it’s my medication!!) but it was not only time slow, but also confidence sapping.  I just didn’t believe my own workings and it didn’t even look right on the dry run but right it was. Some optical illusion!

After cutting the camshaft blank I did compare it with the broken camshaft and there is a little variation on the damaged camshaft which may have also disrupted my approach to the work.

My next session will entail making another cam blank but in steel that I will try and harden. I may also need it if I make a mess in applying Steve Huck’s cam turning technique. Now I have done the first blank I am sure the next one (and future camshafts) will be done much quicker. My aide-memoir worked even if I didn’t believe it and I will write it up properly, laminate it and put in the Seal box of bits for the future. I don’t want to got through the last couple of sessions again. No point in learning a lesson if you don’t remember it.

My next task was to stick the 360° paper template onto the cam turning fixture and then I called it a day. photo]

Started today by measuring all the castings and taking notes of the tolerances. I was surprised at the amount they allow.  Also laminated anything that moved so it will last the time needed to build the engine.

The only metal work done was to take a skimming cut of some steel bar for the camshaft blank. I wanted to start with perhaps the most difficult part, the camshaft. I didn't feel well enough to tackle the castings, even with the large tolerances allowed for machining.

It is a start though! I haven't put a timescale (other than the end of the year) on the build but it is the priority project for the year. Enough writing -here are a couple of photo's.

The first one shows the amount of 'spare' casting..... 

The second is the start of the camshaft by skimming the bar which will become the blank....