Bar stock inline four. Westbury seal inspired

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Thank you for the comments guys they really help! I’m finding it harder and harder towards the finish line to maintain a steady and careful pace. There are areas on my other engines that I feel could have easily been improved if I spent just a little more time on them. Although there are still areas of this engine that I could spend more time on I feel that it will still be an improvement in quality over my last engines.
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.
The last few parts have now been finished up. We have two clear polycarbonate engine covers, one for the lower crank case opening and one for the coolant gallery around the liners.


Then I needed to make two angled manifolds, one for the water inlet on the cylinder head and one for the oil filler/ breather. These were interesting to make but quite satisfying.


I had left no provisions for engine mounts so this took a little thinking about. Looking the the seal engine it has lovely neat little mounts cast in. I Came up with some small right angled bolt on mounts. Although this design of inline four should be well balanced I wanted these to be flexible mounts so I came up with this lower foot design to help absorb some vibration.


With all parts now made I began the assembly and set up.

I’m sure the first run or at least first few “pops” won’t be far off now!!
Hey guys, it runs!! Took about 15 mins of cranking over with regular pops to build up compression and I got a couple of short runs until eventually it kept running and just got better from there. The first run was very cobbled together, had a few oil leaks and a borrowed flywheel that wasn’t really big enough for slow running. After the first couple of sustained runs I then made a new heavier flywheel and fixed a couple of oil leaks. I’m now uploading a couple of videos.

Now I need to make a nice base and finish the cooling system properly.

Thank you for all of your comments guys. They really mean so much. After looking at so many of your engines in total awe of the quality of workmanship it has driven me to really try to step up the quality of mine. I still believe I have a long way to go but I am enjoying the learning.
If anyone had any questions or comments I’d like to hear them.

I had a go at making some silicone plug caps for the engine yesterday.
I was inspired by a brilliant and very informative post I found on this subject by Gail Ignition boot molding

This silicone is mould craft gp310 rtv. This is one of the softest silicones they make. I didn’t realise until I had purchased it that I could buy it in different hardnesses. This has been very good to prove the mould and practice with. I have ordered some of the two part putty like Gail uses in the write up.

I had been having a some issues with the spark jumping across the outer terminals on the distributor cap so I thought I’d try setting the cap with its wires into a mould with some of this silicone. It has worked surprisingly well and I’m sure it will be even better with some slightly stiffer silicone.


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