D H Gipsy mk1

[David KParticipant @davidk77137]

I was going to do a full build thread but time and forgetting to take pictures as I went along means it will be more of a quick build.

So i purchased these castings second hand complete with plans ,

It took me a while to decide where to start but eventually took the plunge and started to machine .

Boring through for the cylinders

[David KParticipant @davidk77137]

Brief build thread

[Clive BParticipant @cliveb55652]

Hi David,

Looks like you're making good progress. I have almost finished the crankcase on my own Gypsy Mk1 and am about to start on the crankshaft. Please keep the pictures coming.

Clive

[David KParticipant @davidk77137]

more machining of the end plate

Using an extra long centre drill to mark through for the camshaft

Then open out using standard drill bits

[David KParticipant @davidk77137]

Then the same for the main bearings but finished off with a home made boring bar

Happy with the final finish

[David KParticipant @davidk77137]

Sitting a piece of bronze for the main bearings

I soldered the two halves together before machining, if I was to do it again I think I would use super glue.

Machined then heated and split again

trial fit

[Lee RogersParticipant @leerogers95060]

Thanks for posting this. Memories of freezing cold mornings standing on the cowling and trying to undo the fuel cap with a heavy brass spanner.

[David KParticipant @davidk77137]

I couldn't find a reasonably priced piece of flat bar for my Crankshaft so I ended up machining

some round down to size

I milled out the basic shape

Then transferred to the lathe and machined the bearings. I made some spacers to fit into the gaps between the crank webs but they seem to have disappeared in this picture

Edited By David K on 01/03/2020 16:03:07

[David KParticipant @davidk77137]

I bought some extra long drills to put in the oil ways

Finished crank needed minor alterations to fit into the main bearing caps

[David KParticipant @davidk77137]

Camshaft lobes being formed on the mill and rotary table

Lobes , bearings , spacers and shaft

Loctite the camshaft parts using rotary table and Dial gauge to set lobes

Finished camshaft

[David KParticipant @davidk77137]

Machining shop supplied cam gear

Timing gears with idler gear

[David KParticipant @davidk77137]

Cast iron blank ready for machining to shape for cylinders x4

Cutting the fins with a slitting saw, hated this job , everything was covered in black dust including me.

Recess for the cylinder studs

[David KParticipant @davidk77137]

Boring the cylinders

Finished cylinders

[David KParticipant @davidk77137]

Conrods basic shape

forming the rods on rotary table

Finished rods

[David KParticipant @davidk77137]

Turning the pistons

Milling the cut outs and reaming the gudgeon pin hole

[David KParticipant @davidk77137]

Parting off some piston rings from cast iron

Made a small oven to set the ring gap

Heat to cherry red

rings before fitting into cylinders and adjusting ring gap

[JC54Participant @jc54]

Enjoying your posts David. Could you please explain how the holder for the shop bought gear works please? I am still very much a beginner and have some gears to alter for a clayton steam wagon differential. Many thanks John

[David KParticipant @davidk77137]

Hi , that piece of Alloy I used was in fact an older jig I had lying around from a previous build.

I had cut the four slots so it compressed slightly on my four jaw chuck in my lathe.

As for the gear , all you need to do is turn a recess slightly smaller diameter than the gear and then tap the gear in with a soft mallet. The steel gear will slightly cut into the alloy as its tapped in and this is enough to hold it tight.

Remember to bore a hole through the centre of the jig so you can drift the gear out when finished.

[JAParticipant @ja]

David

It is nice to see a build blog. I have not looked at it very closely but I have a few questions:

1. How long has it taken you so far?
2. Do you know the providence of the castings? You mentioned they were second hand, do you know where they came from?
3. What were the aluminium castings like to machine?
4. Were the castings good to drawing? That is, was there always excess material?

Many thanks

JA

[JC54Participant @jc54]

Many thanks for the explanation David. Just need to dig in the useful box for some alloy of suitable size.

John

[David KParticipant @davidk77137]

Hi JA, Just looked at the date on my first pictures and it seems I have been working on this for just over a year.

Must admit I did not think it was this long but I do tend to make one part or so then take a break.

I believe the castings were made by a ' Les Chenery' , I know there are a few around but rarely come up for sale.

The castings are good , a few small 'blow holes' have appeared but nothing to cause problems. I have tapped a lot of small threads into the casting and they seem to be holding up so they must be pretty good..

Drawings are very good , a few decimal points on the dimensions have been in the wrong place and there are a couple of mistakes but so far the build is going well.

The castings were quite solid and I have removed a lot of material from them , the only place were the material has got a bit thin is the side wall next to the camshaft bearings and cam followers. If I could start again I would move the crankshaft a few thou over to one side which intern would give a bit more camshaft clearance.

[David KParticipant @davidk77137]

Cut some alloy blanks for the Cyl heads

Turned the combustion chambers on the lathe then moved to the mill to drill and cut the valve seats.

Cutting the fins was more problematic than the barrels, I found it better to use no fluid and to cut in the same direction as the saw , 'climb cutting'

[David KParticipant @davidk77137]

Removing more material to form the top shape

Tapping the plug holes, the digital gauge has proved very useful since I purchased it.

Finished Cyl head , I made five so one spare.

[JAParticipant @ja]

David

Many thanks for the reply.

I occasionally look at models of Gipsy Mk.1 engine at show and think that it may be an interesting model to make. When I start a model I always think that it will be a quick build, it never is. Now on my fourth model I am beginning to understand castings:

1. The aluminium used in alloy casts is always nasty to machine
2. I have yet to experience chilled, hard, cast iron but I know that it is a topic of conversation
3. The quality of the casting is always variable, usually poor
4. One has to be careful when setting out the initial datums.

I did have a quick look at a sectioned Gipsy Mk.1 engine this morning. Major Halford was one of the great aero-engine designers and the only one that progressed from piston engines to jets.

I wish you good progress with the model.

JA

[Clive BParticipant @cliveb55652]

Hi David,

I'd be interested to know where you found errors in the drawings. I believe I have found some errors in the camshaft drawing and am redrawing this part in CAD. Also don't buy 10T 32DP gears for parts 151/147 (as I did) without checking the dimensions first.

Regards,

Clive

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