DH Gipsy engine 1/4 scale

[kendo57]

Bought these castings from an internet site , they were made a few years ago and probably
been sat under a bench . They came with a set plans which looked quite daunting at first look.



I Decided to start with the crankshaft , a piece of en8 steel bar was purchased , milled down then the
centres for the main and big end bearings were centre drilled



Then more milling to form the rough shape



Transfer to the lathe , mount between the pre drilled centres and turn the bearings



Quite a lot of work later I have something resembling a crankshaft

[iansoady]

Lovely, I look forward to seeing more.

[Yambo]

Oh goody, an engineering build thread. I'll be keeping an eye on it!

Are you khd?

[Lutin]

Oh goody, an engineering build thread. I'll be keeping an eye on it!

I'll second that.

Top work, that man!

[kendo57]

Are you khd?

Yes I was KHD


So I realised that maybe I should do the crankcase first because if I mess that up the
rest will be irrelevant .

I started by machining the base to give me a datum to work from



Then machined the top flat and bored through for the cylinder openings



I drilled and tapped the mounting holes for the main bearing caps and after machining the cap bases
flat I drilled through the caps and fitted them.
Next I set the crank up on my lathe and bored the main bearings





Also line bored the camshaft bearing

[GuzziPaul]

Great we're getting it from the start. Whish I had the tools and the skill.

[kendo57]

should have posted this earlier , machining the timing gear case on the end of the crankcase.
You can just make out the punch dots used for marking the boring for crank and cam



A piece of phosphor bronze bar to make the main bearings , first it was slit down the middle



The two halves were soldered back together ready for machining, if I did it again I would use super glue



after machining they are re heated and split

[kendo57]

Piece of cast iron is mounted for turning the cylinders



After turning the basic shape the piece is mounted on the mill and the fins cut using 0.5mm saw



Then back on the lathe to bore



Machining channels for the mounting studs



Finished cylinders and you can see I have bored through for the eight camshaft followers.

[Bomble]

Absolutely amazing work. Would It be possible to give an idea of time for each process?

[Lutin]

What a neat way to make the split shells for the main bearings.

Do you need special tooling to machine the cast iron? Looks like it doesn't produce swarf but rather small chips.

Great stuff. Really enjoying this.

[kendo57]

Absolutely amazing work. Would It be possible to give an idea of time for each process?

Not really , it varies so much , sometimes I spend hours and feel I have got nowhere then
other times I have a really productive run. A lot of time is often spent setting up the work piece
and cleaning up afterwards.

[kendo57]

What a neat way to make the split shells for the main bearings.

Do you need special tooling to machine the cast iron? Looks like it doesn't produce swarf but rather small chips.

Great stuff. Really enjoying this.

No special tooling , the cast iron bar I used is really nice to cut and produces a lovely finish.
The downside is it produces chips and a lot of dust , so much that I hate using it.
When I cut the fins I was covered in dust along with my mill and lathe , unfortunately the dust is abrasive
so I needed to strip and clean everything afterwards.
Some cast iron forms a very hard skin when its cast which can be a problem to remove .
I have heard of people having to grind the surface off to get to the machinable material underneath
but luckily the bar I use is not like this.

[kendo57]

Each cam lobe was formed individually out of silver steel then hardened



Eight cam lobes , three bearings , two spacers and the shaft all in silver steel



Each lobe was bonded to the shaft with Loctite using a 360 degree rotary table and dial gauge to set
them correctly



Finished camshaft

[kendo57]

Con rods are roughed out of alloy plate



Then milled to final shape

[iansoady]

It gets better and better. Can't wait till it's started up!

[kendo57]

It gets better and better. Can't wait till it's started up!

no pressure

[Yambo]

no pressure

You gonna remake the piston rings then?

[hilldweller]

Respect with a big R.

A good way to fend off cabin fever.

[G.P]

Marvelous !

I (would) rate this thread a five !

[Skub]

Proper engineering.

Awesome work man.