3 cyl Pip engine

Here you can see the cylinders just needing the second slot finishing on the left
hand rocker posts

With the cylinders drilled and tapped I need to make the valve seats/guides.
These are made n one piece out of 660 phosphor bronze.
A piece of bronze is turned down and threaded m10 fine to match the Cylinder, then
the first 2mm is turned down to 8mm and the step is turned a 45 degree taper.

continued from above
This taper will be the seat for the guide when screwed into the cylinder.
A 3mm hole is then drilled and reamed through the centre, the front half is opened
out to 6.5 mm then a 45 degree valve seat is formed as in the pic below.

I then placed a bit of alloy in the lathe , tapped it m10 and screwed the guide into this
so I can reduce the top halve to form the guide. Two small holes are drilled either side
of the valve guide and a tool is made to insert into these which will allow me to screw the
guides in.

finished guides

While I was making the guide I made a small collet to slide over my 90 degree
cutter to enable me to keep it square while I cut the seat for the guide.

cutting the seat

The guides are screwed in with green permanent Loctite

the holes drilled in the cylinder head actually
came out in the correct place in the combustion chamber. I am happy to say the jig did its job.

Next job is to drill the inlet / exhaust ports.
These are drilled from the centre at a slight angle to the valve guides.
The cylinders are nearly finished so each operation becomes more nervy ,
I would be gutted to mess up now.

You can see from this picture were the drill breaks into the valve guide.

Finishing off the cylinders, I made a jig to cross drill the rocker posts and then
rounded the tops with a file

The cylinder liners are made from seamless 4130 aircraft grade tubing. The tube will only
need a light hone ready for use.
I made an expandable reamer to hold the tubing while I cut the short lengths so I didn't
crush it. I turned a small chamfer on the inside edge to make it easier to fit the pistons.
These will be a push fit held in with Loctite

That's it , all cylinders done , crankcase next

The crankcase has a timing gear fitted inside, this is one of the few items I need
to buy for the engine. It is an internal ring gear , 60 tooth , 48dp which I managed
to buy from HPC gears . The gear will need reducing in width and diameter so I
turned a boss on the end of some alloy bar. The gear was then tapped onto the boss and this was enough to hold it
in the lathe.

I then transferred it to the mill and drilled the holes for mounting .

To start the crankcase I cut a piece of alloy bar and mounted in the lathe.

After turning the ends square I started to turn the inside to the dimensions shown
in the plans. These consist of shoulders and pockets for the bearings, ring gear and clearances
for the crankshaft.

Then the outside is turned to shape

The crankcase is transferred to the mill and a flat is milled at 120 degree intervals
and a .75 inch hole is turned central on each flat for a snug fit of the cylinder liner.