# Wallaby  30cc 4 Stroke



## bezalel2000 (Jun 2, 2011)

EDGAR WESTBURY Published the Wallaby in Model engineer 1962 -I was too young to appreciate it at the time but I think its time I should give it a go.

First step - get the castings - better yet Edgar provided pattern drawings for the Wallaby so I best start there.  :

This is my first model engine so I have no idea how long its going to take or how much help I'm going to need - but nothing ventured nothing sprained :big: Got to start some where

To night I started on the pattern for the engine block. Only got part of the right side of the block done and partly filleted. 

I'll add on as I go.







The two lumps on this side of the engine are the oil filler and the radiator hose mount







Since this is going to be a split pattern this is just the first side - the other side has a few more complications I need to work out.


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## steamin (Jun 2, 2011)

Awesome undertaking, pattern making and pouring castings is one phase of model making I have not ventured in too. So I will be following your process with great interest. Thanks for wanting to share.


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## metalmad (Jun 2, 2011)

Good one Bez
often taking the first Bite out of that elephant is the hardest :bow:
Pete


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## bezalel2000 (Jun 2, 2011)

steamin  said:
			
		

> I will be following your process with great interest.



Thanks Steamin

 I'll try not to run you astray in the pattern making department.



			
				metalmad  said:
			
		

> often taking the first Bite out of that elephant is the hardest :bow:



Its taken a while to work out if I should start at the trunk end or the tail ???


Bez


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## steamer (Jun 3, 2011)

Hi Bezal,

I've contemplated this build for a while..but not from the raw pattern stage!

I'll be watching! ;D

Dave


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## bezalel2000 (Jun 3, 2011)

steamer  said:
			
		

> I'll be watching! ;D
> 
> Dave



Well I best not stuff it up then.  :big:


Ive got the camshaft side of block done.
I'm using a water based filler for the pattern fillets I'll take some photos when its dry - don't really want the camera gummed up with that stuff,  

Bez


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## Herbiev (Jun 3, 2011)

Hi Bez. I'll be watching too. Thanks for sharing :bow:


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## metalmad (Jun 3, 2011)

Hi Bez
This gunna be a fantastic post and looking at the drawings of the Wallaby not an easy one.
Making the castings show a whole other side to making engines and u really have my attention.
Pete


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## steamer (Jun 3, 2011)

I started laying out a "Billet" version some time back...but the project list is long..
http://s164.photobucket.com/albums/u27/mcandrew1894/?action=view&current=WallabyAsm.jpg

From what I've heard, the commercial castings are a bit rough, though in fairness, I haven't seen them...but man!  $$$$$$$$$$ !  Big bucks

Dave


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## 90LX_Notch (Jun 3, 2011)

Awsome, I would love to have a home foundry one day. Best of luck with this build. I will be watching this one.

-Bob


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## bezalel2000 (Jun 4, 2011)

steamer  said:
			
		

> I started laying out a "Billet" version some time back...but the project list is long..
> http://s164.photobucket.com/albums/u27/mcandrew1894/?action=view&current=WallabyAsm.jpg
> 
> From what I've heard, the commercial castings are a bit rough, though in fairness, I haven't seen them...but man!  $$$$$$$$$$ !  Big bucks
> ...



That's a neat CAD Dave, is that in google scetchup? 


and Question 2. do you know if the wallaby design is copy right or public domain?

Bez


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## lordedmond (Jun 4, 2011)

be careful how much of the plans you show as they are copyright 

http://www.hemingwaykits.com/acatalog/The_Wallaby___Edgar_T_Westbury.html


Stuart


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## steamer (Jun 4, 2011)

The CAD model was made by me using Alibre.  The geometry was created by me and is not a duplicate of the Wallaby, but a simplification....to make it easier to whittle out of solid.  NO copywrite infringement there

As to copywrite, your right...I wouldn't publish the plans on the forum.

However, what you have done so far I "think" is fine...Hemingway publishs all of that on their website...but go easy with it.

Dave


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## bezalel2000 (Jun 4, 2011)

hi lordedmond

Thanks for the copyright info I wasn't sure if Westbury had assigned the rights to anyone.

I guess we just have to wait another 9 years before it becomes PD (4 May 2020)

Good pickup on the copyright thing in the backdrop to my photos. I hadn't given that a thought (re: copyright), they were just "A nice backdrop" to cover the paint pattered benchtop. I'll watch that now I'm mindfull of it.

 and thank to you too Dave 

Bez


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## bezalel2000 (Jun 4, 2011)

Hi Guys

I chopped up some more wood yesterday for the cam shaft side of the engine.
A couple of blocks for the push rod guides and half a cylinder for the cam shaft housing which runs the full length of the block.

The half cylinder starts life as a chunk of pine that's been kicking about the workshop for a few months now  So lets turn that into sawdust.






While I was turning this cylinder it occurred to me that a few metal machinists may not know how to turn soft wood without finishing to size with sandpaper. So I posted a How to at 

http://www.homemodelenginemachinist.com/index.php?topic=14644.0 


Here's a few of the bits that make up the cam shaft side of the block.







Well it feels a little embarrassing exposing my naked patterns this early,

but I guess you won't get to see how it got that way if it just turned up sparkly and true.

After assembly it starts to look a little rough, the fillets are yet to be cleaned up and the matching faces still need to be trued up, the top bottom an side draft is still approximate.
but it is starting to look a little like an engine block.












Stay tuned, there is more to come

Bez


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## bezalel2000 (Jun 8, 2011)

Slow progress yesterday

Just added some paint and the sump (outer only - no core yet)


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## metalmad (Jun 8, 2011)

Wow It looks great 
Starting to look like an engine aready :bow:
Pete


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## bezalel2000 (Jun 11, 2011)

Finished adding the flange to the sump pattern today

The important thing with patterns is Good draft, smooth surface and filleted internal corners,

This sump has a lot of (almost) vertical surfaces so I need to pay particular attention to the other two aspects to help compensate, otherwise I'll have trouble drawing it out without damaging the mould 

here it is before the clean up.


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## steamer (Jun 11, 2011)

NIIIIIIIIIIICE! ;D

Dave


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## BillC (Jun 11, 2011)

Beautiful work!

Here's mine...


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## steamer (Jun 11, 2011)

Thanks for that Bill!

I noticed you put in the optional power take off, off the end of the cam that Westbury describes...and also a belt driven water pump

Both things I've considered....NICE looking engine!

Dave


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## BillC (Jun 11, 2011)

Thanks Dave.

I've always been a fan of Westbury and his model engineering. That compensating carburetor works very well too. He designed it for the locomotive that this Wallaby engine was intended for and the engine runs so well that I use it to tune new experimental carburetors too. 

The water pump needs a top bleeder tube which I have never gotten around to. I also had to make a windage tray and oil relief valve to keep so much oil from being flung up under the pistons. Before the rings finally seated, the plugs would oil foul after just a very short run - but breaking the rings in helped too. That oil pump will do some serious oil pumping and actually too much....


Keep rollin' Bez, you're doing great....(keep in mind that some folks buy two casting sets when they decide to build an engine - in case a casting might go out a window or something like that....  This engine was a joy to complete and has been a joy to run - you're gonna love it!

I do some castings too. I made an odd side pattern for an oil pan for a Wall Four that I'm working on. Casting is addictive. I've got to show off my drill press! I'm anxious to see you do these castings!

BillC


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## bezalel2000 (Jun 11, 2011)

Thanks Dave

The sump is cleaned up a bit now and I'm waiting for the paint to Dry - so more Pix when I can handle it again.




			
				BillC  said:
			
		

> Here's mine...



Bill 

A real big thank you to you, you have no idea how much I needed to see some good photos of the real thing. :bow:

or did you :-\

Good pictures o a lot better than 2D drawings.


So now, thanks to your pix Bill, the block pattern I made was apparently just a practice run ;D 
I can see all my errors in reading the drawings.

1. It looks like the cam housing is the wrong diameter; and

2. on the other side ( as you can see in post #15 the water jacket outlet flange is at the wrong end of the block) it was the wrong shape anyway :big:


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## bezalel2000 (Jun 11, 2011)

Well the paint's dry 












Next up - Timing Cover ? :-


Bez


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## BillC (Jun 11, 2011)

Bez,

The block is a complex casting...The core needed is almost as intricate as the outer block. I believe you are going about this right because when I machined this one I saw a few things that I would have done differently but working with the casting as it was did fine. The oil gallery under the cam is due some scrutiny. That is an area that I would change to have all of the oil lines inside of the castings and no external lines except to and from the pump and you could do it quite easily in your instance where you are making your own patterns....

I made a spring loaded oil relief valve (brass part on the line above the pump) and a small needle valve to adjust the volume of oil to the crankshaft. As I said; I made a windage tray for the bottom end because of the amount of oil that pump was delivering - but: that would not have been necessary if I had done the relief valve and needle valve first.

I will be happy to take some photos of this 'nude' block casting if you would like.....Sometimes a drawing just doesn't do it!

BillC


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## metalmad (Jun 11, 2011)

Looks like someones been busy !!
It looks wonderfull.
I can not wait till the pour :bow: :bow:
Pete


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## steamer (Jun 11, 2011)

OOOOOH I like it...!

Dave


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## bezalel2000 (Jun 12, 2011)

BillC  said:
			
		

> Bez,
> 
> The block is a complex casting...The core needed is almost as intricate as the outer block.



Thanks Bill
I did a concept sketch of the block core a few weeks back, which I thought would look something like this;





If its way off, now would be a good time to find out. the rectangular section is the water jacket, the cylinders are long but its nearly all core print.



			
				BillC  said:
			
		

> The oil gallery under the cam is due some scrutiny. That is an area that I would change to have all of the oil lines inside of the castings and no external lines except to and from the pump and you could do it quite easily in your instance where you are making your own patterns....



I would like to look into that, on the subject of oil - in particular, the filter and it's connection point. this is not looking too good with this pattern as I thought I could get away with a one piece pattern.
I have rammed up a test mould and the out side of the sump slides out real nice. The sump's inside with its internal filter connection point is a whole different story. In spite of the heavy draft angle it is still to deep for the pattern to slip off without braeking off the core. It looks like I have little choice but to make a separate core. not a bad thing overall as I can make parallel sides on a separate core, and that should overcome the oil filter connection issue.








			
				BillC  said:
			
		

> I made a windage tray for the bottom end



My ignorance to the fore here, what is 'windage' ? ??? ? I was expecting this thing the burn gas not make it.  :big:




			
				BillC  said:
			
		

> I will be happy to take some photos of this 'nude' block casting if you would like.....Sometimes a drawing just doesn't do it!
> 
> BillC




Please hold that thought, I might just cash in the offer if it all starts to go a bit pear shaped here. 
although thinking about it - in cross section, the bottom half of the block and sump is supposed to look a bit pear shaped anyway,



and I got the Timing Cover started, but there is still lot more work to be done there yet.







Bez


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## metalmad (Jun 12, 2011)

Hi Bez
A Windage tray is a short tray on the top of the sump that stops too much oil splashing around inside the engine block and can help bed in rings with hi volume oil pumps etc


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## bezalel2000 (Jun 12, 2011)

Thanks Pete, I've not heard of it before

Bez


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## BillC (Jun 12, 2011)

The windage tray prevents the oil from being swept up out of the oil pan by the turbulence of the whirling crankshaft and connecting rod big ends. It's made of sheet metal curved in a half circle and placed so that there is very little clearance from the crankshaft. Normally fitted in dry sump engines. It is used to keep the oil in the pan and prevent excessive oil on the cylinder walls - too much oil on the cylinder walls will force by the piston rings and accumulate on top of the piston basically preventing the engine from running.

The boss on the side of the oil pan is the oil pump sump pickup connecting point. The pickup lays in that side of the pan. There is also a boss on the bottom for a drain plug.

Your block core doesn't have water jacket spaces around the cylinder liners...the water jacket is one large cavity with liner holes at the top and bottom. The engine has wet liners.

I'll hold on any more photos....


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## bezalel2000 (Jun 12, 2011)

Thanks BillC

So much to learn - So little time



			
				BillC  said:
			
		

> Your block core doesn't have water jacket spaces around the cylinder liners...the water jacket is one large cavity with liner holes at the top and bottom. The engine has wet liners.



If I read this right the long cylinders appear to be the sleeves however the long Cylinders are only there to support the weight of the core in the mould the sleeves are inside the water jacket and therefore not visible - below the water jacket needs boring out to the correct depth to fit the sleeves. 

 it may look different if I draw it this way;

(if you click on the image you'll get 3D walk around)







Bez


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## bezalel2000 (Jun 12, 2011)

BillC  said:
			
		

> There is also a boss on the bottom for a drain plug.



Yep, I need to remember to add that too  :

Bez


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## willburrrr2003 (Jun 16, 2011)

What a really nice job making your patterns  Sand casting is such a fun even in it's own right, but to make an engine from it is even cooler huh  

Regards,


  Will R.


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## bezalel2000 (Jun 16, 2011)

Thanks Will 

I'm having fun - and its a challenge

Your never absolutely shore the pattern is right until the metal goes hard :big:

Do you do your own casting ?


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## willburrrr2003 (Jun 17, 2011)

yes I do, been awhile since my last pour though... have to build a new lid for my foundry. I can see myself doing several pours for this hobby though  I got into sand casting through the Dave gingery series of backyard metal casting, I built the foundry and have halfway completed my gingery lathe. I haven't done anything with it since I moved a couple years ago ...at that time I came into a good deal on a mini-lathe and then cnc'd it.  I would like to finish the lathe though and may start back on it soon.


Regards,

  Will R.


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## BillC (Jun 19, 2011)

Hi Bill

I wonder would you mind giving me a little more detail on your thoughts about running internal oil lines. 

In particular what changes would I need to make to the patterns to permit these internal oil lines.

I'd be happy to discuss this publicly, in the thread if you wish, but I just wanted to ask privately first.

With the experience you already have with this engine I'm keen to make use of that experience if you are happy to help me with it.  

kindest Regards

Bez
-----------------------------------------------------------------------------------------------------------------------------------------------------------
Bez, 

I would incorporate a boss on the oil pump end of the block for an internal oil relief valve, then allow a means to drill the delivery lines internally. The needle valve is a basic restrictor and could be included at the point where the drilled lines intersect at the corner at the end of the main gallery.

Some builders may still prefer the external lines (I used 1/8 brass bent to fit using cerrobend) then nickel plated. They make the engine look like 'real' old school...

Happy to help out Bez, let me know if you need those photos....

BillC


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## bezalel2000 (Jun 19, 2011)

Hi Bill

Thanks. 

currently the timing end of the block has a boss that is shaped to the timing cover itself.

If this extra thickness were extended across the whole block at that end the oil line could feed in any suitable spot.

Directly above the pump outlet looks a good option.

By modifying the Block core, to be cylindrical,(follow the red line) in lieu of following the external surface, it could make room for an oil gallery above the crank shaft (and off to one side). 

An oil feed to each main bearing could be drilled upwards to meet the horizontal oil gallery. (The green line) 

I modified Westbury's sketch to help explain the idea. The Blue section is the core.






Do you think that has a chance of working as intended?

One possibility I may need to consider is to make room for a long twist drill, since longer drills are usually bigger, I may have to reduce the crank to block clearance to minimize the possibility of breaking through to the crank space or worse - out into the fresh air.


Cheers Bez


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## steamer (Jun 24, 2011)

Hmmm I'd leave more meat in that area. The drill will wonder, and the start machining point will too with a casting.

Seems kinda close to me.

If you went to the oil gallery above and to the right, I think you would have more room...

I'll think about it....but of course it's completely up to you.


Dave


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## metalmad (Jun 24, 2011)

Hi Mate
U back from Tassie yet?
Dont forget the Conrod clearance in that area with the green dot Buddy.
U may find, u need it all, once the Crank comes around to 90 degrees. 
When we gunna do the Pour 
Pete


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## gbritnell (Jun 24, 2011)

I agree with Dave. It looks like you could have a problem putting it in that area. While you're making the patterns why not run a longitudinal boss along the outside of the block in the same area. This way you won't have to infringe on the internal room and it will give you enough meat to drill, even if the drill does wander a bit.
gbritnell


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## steamer (Jun 24, 2011)

Hi George,

Maybe up a little just to the right of the breather cap maybe?

It's a tough call.  Not a lot of room!

Dave


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## bezalel2000 (Jun 24, 2011)

Hi Guys

Thanks for the feed back. Some good ideas there.

I've been stranded in T-ash-mania all week, just got back last night. :big:

I like the idea of adding a gallery to the outside. i think I might go that way.

Pete, We should be able to pour a casting this week sometime.


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## bezalel2000 (Jun 27, 2011)

A few posts back I made a trial mould for the sump and found I needed to build a separate core box for the inside of the sump.
I haven't taken any pix of the core box yet, but you'll see how I did when I get some.  

I got a full day in the shed today and Pete got his long awaited look at some liquid metal as we set about to pour a casting for the Wallaby sump. ;D

Unfortunately my choice of gate location wasn't suitable for this shape casting so the first casting was a miss pour. I tried to feed the gate in from end and with the thin walls it just froze up before the mould was full.  :-[

Any way the position of the gas holes showed where the gates needed to be so a second pour gave a better out come.

Disappointing for Pete because he had already left.

Any way here's how things turned out.













Bez


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## metalmad (Jun 27, 2011)

It was a good Day Bez.
I learned a lot and had fun :big:



SANY1752 by metalmad2011, on Flickr




SANY1753 by metalmad2011, on Flickr




SANY1754 by metalmad2011, on Flickr


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## metalmad (Jun 27, 2011)

sorry mate my computers playing up again



SANY1756 by metalmad2011, on Flickr




SANY1757 by metalmad2011, on Flickr




SANY1760 by metalmad2011, on Flickr


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## metalmad (Jun 27, 2011)

SANY1761 by metalmad2011, on Flickr




SANY1762 by metalmad2011, on Flickr




SANY1765 by metalmad2011, on Flickr


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## bezalel2000 (Jun 27, 2011)

Thanks for the pictures Pete  :bow:

It's hard to do a self portrait while your trying to maneuver a bowl of liquid Al.  :big:

I might just add a few words to explain whats in the pictures and how they all fit together.

This sump pattern is a split pattern, which means it separates into smaller parts and part of the pattern is above the parting line in the top flask(the cope) and part of the pattern is below the parting line in the bottom flask (the Drag). 

Here the top half of the split pattern is being rammed up in the cope.


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## bezalel2000 (Jun 27, 2011)

When the cope is turned over ( it is now upside down) and the second half of the split pattern can be added.






In this case the second half of the pattern consists only of a core print to locate the core that makes the cavity for the inside of the sump.


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## bezalel2000 (Jun 27, 2011)

The core is made of sand in this case it is a greensand core so there is no need to bake it.

To make the core the required shape a core box is required.

In this picture you can see the two halves of the core box and the core - note the truncated 4 sided pyramid that matches the core print of the split pattern seen previously.


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## bezalel2000 (Jun 27, 2011)

This next photo shows the core located into the core print in the drag.








After the pouring sprue and runners have been cut out in the cope, the pattern can be removed. (note: this casting is just a little too thin in the walls for this runner to properly fill the mould.






The Cope is then lifted onto the drag ready to pour

When the melt is almost ready to pour - all the lifting hardware is preheated to help keep the metal liquid as long as possible during the pouring operation.






Next step is to fill the mould with metal


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## steamer (Jun 28, 2011)

OK !  AND?

 ;D


How'd they turn out..How'd they turn out? th_wwp

Dave


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## bezalel2000 (Jun 29, 2011)

Hi Dave

That last series of photos was way out of chronological order - Sorry about that. 

The outcome was posted first in reply #43.

Although the results are much better than the miss pour Peter saw, I'm still not fully satisfied with the gating for this casting, because, if you look very critically at the outside of the casting there is evidence of a cold shut running horizontally from the oil line boss. This occurs when the metal traveling in two different paths arrive at the same place at different temperatures.  :-[  In future moulds I will vent the mould better and gate from both sides to flood the mould quicker and this should eliminate this issue. 



			
				Bezalel  said:
			
		

> A few posts back I made a trial mould for the sump and found I needed to build a separate core box for the inside of the sump.
> I haven't taken any pix of the core box yet, but you'll see how I did when I get some.
> 
> I got a full day in the shed today and Pete got his long awaited look at some liquid metal as we set about to pour a casting for the Wallaby sump. ;D
> ...


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## bezalel2000 (Jul 8, 2011)

Its time for another post.

I've been working out how to build the core for the engine block. 






A bit of a challenge because there is a crank bearing seat across the middle of the block separating the two lower halves of the block. each of these separate cavities is connected to the water jacket cavity by a thin length of cylinder. I was a little concerned that this core may not support its own weight in the mould.  I think its sorted now.

Here is the core supported by the core prints at the top and bottom of the block. {after baking}







here is the sequence of events that shape the core in the corebox.






The core box is made up of 4 shaping blocks 2 core prints and the 4 outer boards that hold every thing together.

 The top core prints and water jacket former are placed in the box first.






Next the two formers for the lower half of the block and the bottom core prints are added to the box.






Then two of the sides are clamped into place to line everything up.
The camshaft cavity can't be accessed after the box is closed so it is rammed up while the box is still open on one side. a small wooden reinforcing stick is added during ramming to give some green strength to the core before baking. 






The box is fully enclosed and the core sand rammed up with a 9" nail






when its all rammed up the clamps are removed and the sides taken off.






The top core print former is rapped free and removed followed by 
the water jacket formers.






Next the lower formers are removed.






The bottom core print former also contains the former for the center crank bearing seat. so when that's off - its ready for baking.







This is my first baked core so I followed Tel's already proven formula for core sand - with flour and molasses.

Thanks Tel, that stuff is GoooooooD - I think a few bricks of that will be going into the next dunny I build - That aught to stop the emus kicking it over :big:


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## ShedBoy (Jul 8, 2011)

Thanx for the informative core build up pictures and explanation. Great work and keep the pics coming. What sort of casting sand do you use?

Brock


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## steamer (Jul 8, 2011)

Looking good Bezelel

Dave


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## bezalel2000 (Jul 8, 2011)

Thanks Dave
I see your up bright and early again.

Bez


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## steamer (Jul 8, 2011)

No rest for the wicked.....got machines to design.....


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## bezalel2000 (Jul 8, 2011)

ShedBoy  said:
			
		

> Thanx for the informative core build up pictures and explanation. Great work and keep the pics coming. What sort of casting sand do you use?
> 
> Brock



Hi Brock

My normal casting sand is a fine white (the likes of which is preferred for kids sand pits)
to this I add 8-10% foundry grade sodium bentonite "TRu Bond" is the brand I use. 

Although in Queensland you don't have to buy it - on the unsealed clay roads, on the west side of the great dividing range its just white bull dust. 
You can also buy it as a stock grain feed supplement at any produce store "Tru feed", its the same stuff just a bit granular - their no different at all when wet. 

For the moisture content I use an old spray starch/ Windex bottle to spray and mix till it feels right. A key safety matter when it comes to moulding sand - If the sand sticks to your hand when your mixing it, then it is probably too wet to use without the risk of a steam blow back and that's not good for anyone in the vicinity. 

For the core sand I used the formula Tel described in reply #4 on this thread

http://www.homemodelenginemachinist.com/index.php?topic=1461.msg10683#msg10683

I hope this is helpful.

Bez


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## metalmad (Jul 9, 2011)

Hi Bez
does this mean we can eat the core after its been poured?
U go first :big: :big:


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## bezalel2000 (Jul 11, 2011)

Hay Pete

I don't know how he knows, but Tel says you shouldn't eat the cores after they are baked.

And, I've heared uncooked flour is not good to eat either  : so I won't be joining you in that feast. 

Bez


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## bezalel2000 (Jul 17, 2011)

Family matters have drawn me out of the shed for little while,

but I'm back into it now.

first up I got the pattern for the block finished 









So with that ready I was able to make a mould.











and put in the core I made a little while back.

made of couple of castings to see which way up worked best.

I turns out it is best cast with the cam side up. 












This how the underside turned out both before and after cutting off the runners












and the top with the sump.













The rough surface on the the right side of front end of the casting occurred because the pattern needed trimming to fix a draft problem. I didn't have time to seal it before the melt was ready. It is made of MDF and sucked the moisture out of the surfacing sand leading to a small bit of erosion. Next time I use the pattern it will be sealed.


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## steamer (Jul 18, 2011)

Very Cool Bez!  Oooh Oooh when the video?

Dave


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## metalmad (Jul 18, 2011)

Thats not a bad idea
next time,` I will make a video of Bez doing his magic. :bow: 
I may as well make myself useful :big: :big:
Pete


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## bezalel2000 (Sep 16, 2011)

Wow where did the last two months go? ???

Well Pete was keen to knock some swarf off the new castings so he promptly set about doing just that - in the process he identified there was not enough machining allowance on the top and bottom of the casting.

(Also noticed the height of the push rod boss as published is 1/4" too low at 1-5/8" should be 1-7/8". So that casting is destined for a return trip to the furnace )
I appreciate the sacrifice you made there Pete.

So the pattern was due for some alterations. 3mm on the base and 6mm on the top that should allow plenty of room for a good cleanup.











Now the core prints have moved so the corebox needs to be changed to suit.

(The previous top core prints weren't a good fit in the mold so I'll take the opportunity to fix that up) 

To fixthe top core prints I needed a more precise tapered hole for the top of the core box.

To make this tapered hole, I took an old 1" wood spade drill and ground away to the desired angle (ensuring to keep it cool so as not to lose the temper){the steel not mine} :






carefully checking for symmetry as I go.






Next is the corebox itself, which is now about 9mm too short.

I added 6mm to the top of the water jacket formers - At the bottom I left the corebox unchanged and just made the core print on the pattern 3mm shorter, there by making all correct again - in theory at least.

All that is left now is to cast some more and see what comes out.












and Here it is
















Cheers

Bez


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## fltenwheeler (Sep 16, 2011)

Is that an alien engine? I have never seen an antenna on a casting before.

Tim


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## ShedBoy (Sep 16, 2011)

Beautiful work as always Bez :bow:

Brock


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## steamer (Sep 16, 2011)

Looks Great Bez!

Dave


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## kustomkb (Sep 16, 2011)

Beautiful patterns and castings!

My father is a retired pattern maker.


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## Colh (Sep 17, 2011)

Hey Bez

Did you do a set for me? Remember I left those old pistons with you.

Col


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## bezalel2000 (Sep 17, 2011)

fltenwheeler  said:
			
		

> Is that an alien engine?
> Tim



Hi Tim

No, this one's not an alien - but I must admit there has been a few castings I've pulled out of the sand that didn't look any thing like the pattern I put in it! 

Its amazing what steam can do to your casting if you don't make allowances for it.

Matter of fact that's exactly what these antennae are for.

A 2mm spike is inserted into the corners at the extremeties of the mold.
These are referred to by some as Whistlers as they allegedly make a whistling noise when you fill the mold.

This whistler does two things.
Gives the steam an easy exit from the mold in low permeability (fine) sand, and 
it allows any loose or eroded sand grains in the mold to have somewhere to go, that is outside the casting instead of collecting in the corners and putting pox marks in the casting

Bez


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## bezalel2000 (Sep 17, 2011)

Brock, Dave, KustomKB

I appreciate the compliments.

Thanks

Bez


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## bezalel2000 (Sep 17, 2011)

ColH  said:
			
		

> Hey Bez
> 
> Did you do a set for me? Remember I left those old pistons with you.
> 
> Col



Hi Col

Yeh! about those pistons-
They're Just big enough to get jammed in the top 1" of my graphite crucible. 
Took forever to get it out again. (ah! I just remembered what I've been doing the last two months) ;D
Too hard to chop up in the band saw 
They don't want to melt in the normal temp range of typical Al Alloys. ???
They're still as hard as nails at 600*C +. and you can't even break pieces off the skirt even when its glowing. :'(


The good news is the chips do dissolve in liquid Al - eventually  :shrug:

 :idea: I might just plug up the gudgeon pin holes and use them for crucibles :big:


That said I acknowledge your kind gesture :bow: of leaving me 10Kg of ................... 
"??Something??" metal that we all thought was Cast Aluminium, so I'll throw a core in the oven for you and use some different Ali that's got less Titanium and or Chrome in it. 
I'm assuming you want to be able to machine it when you get it. :big:

Oh! if I don't get it done by Wednesday Morning when are you next in town?


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## ShedBoy (Sep 17, 2011)

Thanks for the whistler tips Bez, handy to know. My problem is remembering all this info when needed, always seem to click after it is needed. Dam hindsight.
Brock


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## bezalel2000 (Sep 18, 2011)

ShedBoy  said:
			
		

> [it] always seem to click after it is needed. Dam hindsight.



Yep, the casting often tells me I forgot something in the mold preparation. Too late then, just call it 'On the Job Training'.

Steam holes are a big problem, particularly with thin castings when some times even a stack of whistlers don't cure it.   :wall:

That's when a little extra head pressure does wonders.







Not recommended for use with an open top riser.  *club*

Removing both ends of the can is recommended, for getting the best results.

Bez


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## metalmad (Oct 1, 2011)

I really doubt, u will have much of a shortage Mate :big:


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## bearcar1 (Oct 1, 2011)

Beautiful, clean work Bez. I only messed around with casting in high school shop class about a gazillion years past and my grandfather made quite a few patterns and had full size castings made for steam engines he would build. Your work brings back some memories for me and has also been quite informative. Well done indeed Thm:
I am truly enjoying this thread and will be watching the progress attentively.

BC1
Jim


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## bezalel2000 (Jan 16, 2012)

Thanks for the compliment Jim.

My apologies for not responding directly and also to anyone else who may have fallen asleep waiting for my next post. 

My SWMBO projects are complete now (I think ) :hDe: So here it is.


The Connecting Rods.

Looking at the drawings I decided that this might best be done on the mill in 1/4" Ali plate.

I could machine one half of the con-rod and use the same pattern on both sides of a match plate. (I'll show how this is done latter). For now I have to work out how to mill this thing, since there is only two pairs of surfaces that are parallel. One parallel with the parting line the other ( the sides of the big end ) is too short to be much use.   

I drilled the locating dowels 4mm at the center of both big end and little end. 






This i can use as a reference that is parallel to the centre line. With a Piece of 1/4" key stock I could dial in the job to be straight on the rotary table and clamp down. 

I needed to mount it on the rotary table to get the sides of the rod lined up correctly at 1.55o ether side of the center line.









A 6mm ball nose cutter would thin out the web between the two sides. 

So offset the rotary table 1.55o cut inside and outside of the line down one side from little end to big end.

Rotate the table 3.1o cut both sides of the line on the other side.

That should do it right?


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## bezalel2000 (Jan 16, 2012)

Well, apparently, Ali plate, a brand new rotary table and my current skill set is a less than ideal combination for making conrod patterns.  Nuff said ;D

Time to find a different way to attack this.

Basically the con rod is a 7/64" thick plate with a channel down the middle and a round piece added on at each end.

I have some perspex about that thick and the round bits can be made on the lathe.

line it up as before.







Cut the channel and the outsides at 3.1o.







drill a 4mm hole through the center of each round piece and push them onto the 4mm pins already in place.

The round piece at big end is cut in half and a 5mm spacer added to allow for a kerf to cut the big end in half to fit on the crank.









The out side shape is then cut with a scroll saw with the table set to about 4o to get the draft for the pattern to drawer out of the mold.


then the pattern is trimmed up on a sanding wheel. 
The wood block on the Dremel table is tapered to about 4o to maintain the draft angle while sanding.


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## bezalel2000 (Jan 16, 2012)

Using a match plate

The match plate should doweled to the flasks so that it cannot be incorrectly oriented.

Then the pattern dowel holes are drilled into the plate such that they line up with the dowel holes that are exactly on the center line of the half pattern.

With the flask, match plate and pattern doweled together in the flask the sprue and runners can be added.







When rammed up the flask can be inverted, the match plate lifted and the half pattern removed.






The match plate is replaced and the half pattern fitted to the same dowel pins, but on the opposite side of the match plate.







The drag is then placed onto the match plate (the flask will be inverted again later) with longer dowels lining up the flask and match plate if required.






The match plate, the half pattern, runners, sprue, risers and gates can all be removed from the mold before closing ready to pour.






you will notice that the cope has a divider and is only half filled, this is because I wanted make another half pattern in the same flask. without ramming up a whole flask just for a 20 gram casting. ;D


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## bezalel2000 (Jan 16, 2012)

Well we had a brief break in the rain.

So I grabbed the chance to heat up some metal.

I wanted to use ZA27 alloy on this casting for the bearing quality and strength.

This is how they looked coming out of the sand. 







and after a quick buff up (it takes quite a nice shine )






Thats all for now.

I'm off to make a piston

Bez


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## metalmad (Jan 16, 2012)

Looking great Bez
I can not wait to get my grubby little hands on em :big:
BTW did you take any pics when you cast up the Timing cover?
Pete


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## bezalel2000 (Jan 17, 2012)

Hi Pete

yes I have got some pix of the timing cover.

The timing cover pattern is a one piece pattern.

here it is looking at the inside (obviously) ;D






Below it is laid out in the flask with the other patterns and runners.






When rammed up and turned over it looks like this before the sand goes in.

The small redblocks are the gates joining the runners to patterns.
The long red bar is a riser connection to assist in flow of the melt through the cavity
Inside the timing cover there are three clouts pointing up. 

These are necessary because the inside transition at the parting line is quite sharp and consequently the sand core is very weak at this point.

The clouts provide additional strength to the mold and prevent the core tearing away from the drag during rapping of the timing cover, prior to lifting off the pattern.






Bez


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## bezalel2000 (Mar 11, 2012)

Well It has been a while since I posted. The best excuse I can come up with is the motor on the wood lathe kicked the bucket. This led to a range of challenges that have finally been overcome and we can get back to the wallaby castings.

This next casting or pattern at least is the piston. 

The outside of which is little more than a very short broom handle. The reduction in diameter is a chucking piece this will be left in the chuck when the finished piston is parted off.












.

The cone is the core print to hold the core in place. 

The inside is a little more complicated, with a reduction in diameter near the top and spigots (if that's the right term) for the gudgeon pin to pass through. about half way up.

This will be an interesting core box.

Here are a set of cores fresh out of the oven.






And this is the core box, with the two gudgeon pin bosses ready to insert into the core box to leave metal for the gudgeon pin mounts.






I planned to use Zinc allow ZA27.  I wasn't sure how much shrinkage will occur around the core. (as it turns out, there is Nil shrinkage around the core) so there are two different size core boxes in the block.

Bellow is the core print pattern that sits across the end of the core box to make the end of the core tapered to fit in the core print in the mold.






Core box partly assembled.








Ramming up the core 







The finished Core 






From here the cores are baked for about 40 min. 180oC

Here is one piston, out of the first set of pistons cast. The inside diameter is oversize 

So the next ones will made using cores from the smaller end of the core box.






It shouldn't be a major problem that there is a little eccentricity between the inside diameter and the outsite diameter as the outside has to be machined be concentric anyway.


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## metalmad (Mar 11, 2012)

Hi Bez
Those pistons are looking very slick my friend :bow:
For those who do not know, Bez cast up the Block, Sump and Timing cover for my current Work in progress "The Wallaby"
The Castings are excellent with no hard spots or blow holes.
As this is my first castings Engine its difficult for me to compare with others, but its hard to imagine they could get much better although im sure they will!!
Pete


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