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3 cyl Pip engine

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David Kenyon 209/01/2019 19:19:55
205 forum posts
151 photos

Valves first start off with a length of silver steel

Reduce the shaft to just over the valve shaft diameter then cut the groove for the collet.

David Kenyon 209/01/2019 19:21:20
205 forum posts
151 photos

Now reduce the shaft for the whole length of the valve until a nice fit into the guide

David Kenyon 209/01/2019 19:22:51
205 forum posts
151 photos

Next turn the top slide to 45 degrees and cut the valve face

David Kenyon 209/01/2019 19:25:09
205 forum posts
151 photos

Part of the valve

Flip the valve in the collet and using a grinding stone finish the valve face

David Kenyon 209/01/2019 19:26:24
205 forum posts
151 photos

Then repeat to make six plus two spare

Ryan Norton18/01/2019 11:22:39
190 forum posts
774 photos

Beautiful work!

David Kenyon 218/01/2019 20:10:30
205 forum posts
151 photos

Cheers Ryan

David Kenyon 218/01/2019 20:11:18
205 forum posts
151 photos

Rather than make each rocker individually I machined the rocker profile along a piece
of bar and then parted off each rocker from the bar.
Starting off with a 22mm round piece of Stainless mounted in the lathe , faced off and centre drilled
both ends then a 5mm hole is drilled then reamed through the centre.
The piece is then mounted on the mill using the rotary table and start milling the shape.p1040768 (medium).jpg

David Kenyon 218/01/2019 20:12:11
205 forum posts
151 photos

Next a set of 1.6mm holes are drilled p1040773 (medium).jpg

David Kenyon 218/01/2019 20:13:01
205 forum posts
151 photos

and then tapped m2 for the adjusting screws p1040773 (medium).jpg

David Kenyon 218/01/2019 20:13:45
205 forum posts
151 photos

The profile can be seen here
p1040774 (medium).jpg

David Kenyon 218/01/2019 20:14:22
205 forum posts
151 photos

Each rocker is then parted off
p1040775 (medium).jpg

David Kenyon 218/01/2019 20:15:32
205 forum posts
151 photos

To finish the rockers I then carefully milled the sides down to size p1040776 (medium).jpg

David Kenyon 218/01/2019 20:16:52
205 forum posts
151 photos

Then after a de burr and clean I pressed in a bronze bush , fitted an adjusting screw
and then fitted them to the cyl head.

You can also see the valve caps I made but forgot to take pics. p1040795 (medium).jpg

David Kenyon 218/01/2019 20:20:44
205 forum posts
151 photos

The engine works similar to a 2 stroke in that the fuel is fed into the crankcase and then
transferred to the inlet ports.
The diffuser is basically a fan designed to push the fuel mixture around the crankcase.

David Kenyon 218/01/2019 20:21:32
205 forum posts
151 photos

Starting of with some Alloy bar in the lathe the piece is turned to correct diameter
and a groove is turned to mark the depth of the fan.
A 5mm hole is drilled through the centre and this is then opened out to accept two
press fitted bearings 9x4x4

p1040812 (medium).jpg

Edited By David Kenyon 2 on 18/01/2019 20:22:52

David Kenyon 218/01/2019 20:23:48
205 forum posts
151 photos

The piece is then transferred to a rotary table placed on the mill table vertically.
A series of holes are drilled 15 degrees apart either side of the 180 degree mark.
These holes will have small pieces of steel inserted in them later to enable balancing
the fan.p1040813 (medium).jpg

SillyOldDuffer18/01/2019 20:24:05
4838 forum posts
1017 photos

Good stuff David - please keep the updates coming. Don't get discouraged if not many people comment directly - build threads tend to be enjoyed quietly.


David Kenyon 218/01/2019 20:25:30
205 forum posts
151 photos

The rotary table is then placed horizontally and a 4mm hole is drilled .312 inches off centre,
this is the same measurement as the stroke of the engine as the fan is driven from a pin
inserted into the big end . You will see this in a later picture.
The table is then tilted 15 degrees and a 3mm end mill is used to start cutting the fins at
30 degree intervals.

p1040816 (medium).jpg

David Kenyon 218/01/2019 20:27:46
205 forum posts
151 photos

The mill is moved along the 'y' axis and a second set of cuts make up the rear of the blades

Then its just a matter of removing the waste between the fins

p1040819 (medium).jpg

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