So next up was the oil sump, this has had to be made in two parts as I didn’t have the material to make it from one. It has and intermediate spacer to lower the oil pan. The lower oil pan was machined out using a fairly blunt 13mm ball nose end mill. Having only had the mill for around four months my stock of milling cutters is fairly limited at present, I need a few projects under my belt to work out what sort of arsenal I should put together. This still worked ok it just didn’t leave the nicest finish. The radius on the outside of the oil pan was cut with a 1/4” radius wood router cutter.
The lower oil pan also needs to have an oil retaining tray, according to the build notes for ET Westburys seal engine this is designed to help stop the big ends making a dent in the sump oil as with the big ends rotating at higher rpms there wouldn’t be enough time for the oil to return. I think that the theory is that the holes in the pan let oil through but as the big ends swing around it has no where to go but to be swooped up by the big end.
This pan needs to be as closely fitted to the crank as possible. It took me a couple of tries with some plasticine (from the kids toy box) to get this clearance about right.
The cams for this engine weren’t too much of an issue as I already have my cam grinding jig that I made during the build of my v twin engine. This produces in my opinion fairly good repeatable individual cams that will be locked into place with a grub screw. I do have some excellent instructions from another very kind member of the forum on how to produce the cam for this engine as one piece but for now a built up cam will be fitted.
The cam followers were made from water hardening silver steel they were given a slight radius, drilled down to within 3mm of the bottom to help keep them light and then hardened. This is the first time I had used water hardening silver steel and I am very impressed with how hard it became.
Next up is the distributor, in the plans for the seal engine this has the ignition points built in but I am hoping to have try with some sort of electronic ignition set up in the future so I have built distributor with no provisions for fitting points inside, for now the points will be mounted on the opposite end of the cam shaft. This distributor is probably a fair bit larger than it needs to be but it’s my first one so I wanted to keep it simple for now. If everything works ok there’s no reason why I couldn’t have a go at making a smaller one. I’m not sure how small you could go without the spark jumping across the electrodes inside.
The inlet/ exhaust manifold was next. Again this was a learning curve for me to match up two halves with mirroring cutouts. Thank goodness for the digital read out is all I can say! I might have a go at another manifold with slightly different design once the engine is proven, I’m wondering if I could make the manifold a fair bit slimmer as the ports are only 6mm round then drill the exhaust ports right through both parts of the manifold to the outside and mount a tubular manifold onto that, this might help keep some of the heat out of the manifold.
I have nearly finished all the parts I’m just trying to put together the write ups for all the parts as I get chance. Whilst we are on lock down here in the uk we have our children 6yrs and 2yrs at home 24/7 so I don’t get a lot of spare time. This means that when I do I don’t want to be sitting indoors on the PC. I want to be out in the workshop finishing off the last few parts.
I’m finding it difficult to not start a careless sprint to the finish line as cant wait to hear this engine run! The first time you hear an engine running is so good. Hearing the voice of the working engine you have created from chunks of material. Also I don’t want to finish this and then end up with weeks more on lockdown and wish I had spent more time on finishing parts. I’m trying to come to a compromise between getting it together to hear it and making sure he parts are finished to a good enough standard.
Thanks for reading guys, your comments really help push me to better the quality of the parts I’m making.
