Bar stock inline four. Westbury seal inspired

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Aug 24, 2019
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I have held off from starting any build threads on my last three engines as I have never really been sure that they wouldn’t just be a lost cause. After completing my last engine (the three cylinder radial) which was a great success for me, I think I just need to have a little more confidence in my self.

So it looks like I am starting my first build thread. I am still very much new to machining having only had the lathe for three years and the mill for a couple of months so I really am very open to any advice, criticism or other alternative methods of building or machining parts.

I’m starting an engine based on ET Westbury’s seal major. This engine is usually made from a casting kit but I am having a go at building it from bar stock. I was going to build it just taking inspiration from pictures of the engine found online. So far I have the crank case started and the cylinder liners and valve cages made up. I really wanted to build this engine like my last three engines with no plans at all but after giving it a lot of thought it decided I would purchase the plans and build notes for this engine. I feel that I might learn more from seeing how plans etc are actually drawn up and followed. Although mine won’t be following any of the dimensions from the plans I will definitely be using them for inspiration.

I am looking at 22mm bore and 24mm stroke but this may change. I have purposely left the liners quite thick so that I could over bore the engine later if I feel like it.

There are a few aspects of this engine I’m not completely sure how I am going to approach yet but as with my last three engines most things were decided or adapted as the build progressed.

I am going to try my best to keep a few slightly more detailed notes on this engine than I have on any of my last ones.

Looking forward to having you guys following along with me on this one.

Thanks for reading guys, I will get some progress pictures up soon!
Hey, I have been very busy in he worship and not keeping up to date with the build thread. So much more pictures than info. I will do my best to give a description of all the pictures.

Here we have a rough kit of materials and a little marking out.

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Here I am opening up what will be the lover crank case and drilling the bolt holes for the sump.
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Here I am boring the cylinder openings for the cast liners.

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Here I have drilled out the holes for the one piece valve guides/seats and opened out the valve chest.

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Here I have opened up what will be the water jacket around the cylinders.


I have also made the valves, pistons and liners, crank, bearing housings, and timing case for the timing gears. I will upload more pictures soon. Thanks!
I’ll keep posting pictures until I am up to my current stage then hopefully I’ll try my best to talk through my work as I progress.


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Here are the liners and pistons. The liners are made from meehanite and lapped to size on a home made brass lap with fine grinding paste. The pistons are made from 7075 aluminium. I plan to make the rings from the same material as the liners. Due to some poor machining on my part the top lip on all of the liners came out at different heights. Due to this once the block has had a final cut the chamfer on the top of the liners to help insert the pistons will almost disappear on a couple of the liners. I am hoping I can make something like an oversize valve seat cutter the help re machine the chamfer. The same poor machining also applies the the valve seats so the same thing will need to be done here. Apart from these snags things seem to be going well. I have started on the con rods now, obviously I am making split rods which is my first attempt.
I would probably say that this is possibly not the correct way to make these rods but it’s the way I am attempting to do it. I would love to be corrected if I am choosing the wrong path.
Firstly I marked out all the locations for the bolt and oil holes, these were centre drilled and the bolt holes drilled to tapping size. Then enough material to make the rod caps was sliced off. The bolt holes in the caps were drilled for clearance and the holes in the remaining material were tapped for the cap bolts m2.5 I’m my case. This was a nail biting experience for me . The the faces were finished square and bolted up. Then the material was layed flat in the vice and indicated level left to right and front to back. The first holes were drilled at one end of the rod then the table moved up 52mm for the upper rod eye. Then the big end was opened up to 9.5mm and reamed to 10mm. The small end was the drilled and reamed to 6mm. Now the hard part begins, the shaping of the rod. I countersunk the cap bolts and chamfered the corners. Next the rod was bolted onto the rotary table the have the big end bosses machined, this was a little unsatisfactory as I found it hard to get it perfectly on centre so the bosses came out slightly eccentric. I then switched them over to the lathe. I machined up a 10mm spigot in the three jaw and mounted the rods individually onto this and used a form tool to create the shape. Even on low speed I found that I had a lot of tool chatter. I switched over to using my lathe spindle hand crank and advancing slowly with the tool and some cutting fluid I think produced a satisfactory radius. So this is where I am up to right now. For the angle on the roads I am thinking of using a fixture with offset holes to mount the rods onto individually. Set up in the vise the offset of these mounting holes will give the correct angle. Thank you for reading. Any advice would be great. Thank you!

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Just a suggestion. Instead of putting a taper on each cylinder
just make a single taper ring/hoop. you put this on the piston
it squeezes the rings into the grooves and then the piston/ ring
slip into the cylinder. I use this all the time and it works great.
It also allows you to mill all the cylinders to 1 height.
It also allows a nice gentle taper.
I like this idea, some of the manufacturer special tools that we have for working on motorcycles are piston ring compressors made this way. The only problem I have with this method is that the liners already have chamfers on so one of the liners I think will lose it totally and one of the others only half whilst the other two will keep theirs.

I made a little more progress on the rods today. In between important family duties (children’s nap time) I got a couple of hours in the workshop.

I made my mounting block for the rods to machine the taper up to the small end eye and got all four rods tapered. This was the first time I had tried using a datum point (if that’s what it’s called) and it worked great. You can see the 5mm hole that is drilled in the corner of the fixture, this is where the tool would start from every time a rod was swapped or flipped over. This way no matter how off centre the outsides of the rods were, now they would all be fairly accurate according to the bores of the rod. I also managed to get two slimmed down to the depth the big end bosses were cut to.
My next task is how to achieve a nice radius around the small end eye and decide if and how I am going to add any detail to the side of the rods. I am thinking if I make any detail I can use the same fixture as for making the taper but I can cut the detail into the side face of the rod.

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When setting up on the rotary table, I will often machine a fixture in situ.
My rotary table has a 24mm bore through the centre. I made a shouldered plug which fits in the bottom of the bore and has an M10 thread tapped through. To make a fixture, I turn the end of a piece of stock to 24mm and tap it M10.
The fixture can then be attached to the rotary table with a stud, plus a clamp or bolt into the tee slot of required.
With the blank fixture in place, I can machine a register on the mill true to the rotary table axis.
Thank you that is great advice, I had always machined my register/fixture on the lathe then transferred it to the rotary table. It seems obvious now you point it out that if I machine the register on the rotary table itself then it will be true. Thank you very much!
I finished up the small end rod eyes by hand, this may be slight cop out but I Was very worried about screwing up the rods now after so much work.

I have made up some piston pins drilled them through the centre and made up some brass buttons for the ends , these are a light press fit with some locktite.

Hi all, i have been very busy in the workshop and not really allowing time to keep up dated here. i will do my best to catch up again.

So following on from the last post after finishing the rods and making the pistons i pressed in the liners with some "suzuki bond" this is a grey three bond engine casing sealant. I then pressed in the valve chambers with wurth bearing fit locktite.
Due to my apparent inability to make four liners all the same, once pressed home a couple were very slightly proud of the block as were some of the valve chambers so i gingerly milled these flat then gave the top of the cylinder block a face with a fly cutter. This didn't leave the finish i was hoping for, it seemed like the cutter was dragging some cast iron filings over the aluminium and lightly scoring it.


Some of the valve seats were half gone due to my mismatched machining so I made up a valve seat cutter inspired by George Britnell's design. This worked perfectly and I re cut all valve seats to the same depths.



After a light clean up on a sheet of glass with some fine grinding past the finish was satisfactory.

I then built up the crank, rods and pistons into the engine to test fit the big ends, there were ever so slightly tight so these were lapped in with some ultra fine grinding paste. now the crank turns freely and all of my journals line up well. Next i chose to make some gears to drive the camshaft.

These are m0.5 module gears and were made my home made indexing jig. I am not one hundred percent happy with these as one is very slightly eccentric for now it will be ok for setting up but before the first test run i will make another. The cam gear will also turn the distributor on the front of the timing case.


Next up was the cylinder head, this was a fairly straight forward operation, especially now as for the first time i have been keeping drawings of everything that i am making so i knew where all of my cylinder head bolt locations were. The trickiest part was probably the combustion chamber but i think it worked out ok. First the valve reliefs were cut square with the head then the head was tipped up in the vice to start cutting an angle upwards away from the valves and then swapping over to a much larger end mill for the final plunge cut of the squish.
The head was then turned over and the counter bores put in for the cylinder head nuts.


The head was then slimmed down along one side and some water ways machined into it. this will allow me to fit a cover that will sit flush with the spark plug side of the cylinder head.
Next was to angle the head over on its side to drill and counter bore the spark plug holes.


Next on the list was to make up the cylinder head water way cover this was another simple operation. This cover has one row of its own screws along one side and pics up the cylinder head studs on the other. It has a slot cut along its length on the underside to allow the cylinder head to hold a little more water.


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Wow, cool build. This is gone be a big seal.

Keep on Posting your fantastic work.

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