--Got a situation where I need to cast a small 3-cylinder engine
block. Trouble is, altho I have drawings for the engine I'm damned if I can
visualize what the patterns need to look like, to do the crankcase, etc.
Would like to chat with anyone skilled in this, particularly if they live
around the San Francisco Bay Area..
--Thanks,

--
"Steamboat Ed" Haas : Whatever happened
Hacking the Trailing Edge! : to Tom Nelson?
http://www.nmpproducts.com/intro.htm
---Decks a-wash in a sea of words---

On 04 Jan 2006 04:22:01 GMT, steamer wrote:

--Got a situation where I need to cast a small 3-cylinder engine
block. Trouble is, altho I have drawings for the engine I'm damned if I can
visualize what the patterns need to look like, to do the crankcase, etc.
Would like to chat with anyone skilled in this, particularly if they live
around the San Francisco Bay Area..
--Thanks,


I have a few questions and one assumes you have casting experience
and a well equiped machine shop suitable for engine work:

1- What material will you cast into the mold? Iron, alumninum, what?
Because you will want to get the correct 'shrink' rule to start making
the pattern pieces. This is mostly important if you plan to use
existing parts like pistons, crank, cam.

2- Is the engine liquid cooled? Because you need to provide for a
water jacket between the cylinders and outer block, and developing
these core pieces is the tricky part. You also have to find a way to
suspend them in the mold cavity as you pour the metal.

An easy visualization would be to look at an existing block and trace
the parting lines. This will give you an idea of how many sections
were used to cast the part. Pay attention to the position of the
steel plugs (blow, frost, heater hole, core, pick a name). These are
the core pattern suspension holes.

The real tricky part is in the "one off" machining to accomodate
existing crank, pistons, rods, covers, etc. Not trying to discourage
you, but you will be developing this one casting and recasting it many
times to get it mostly right.

Try making the engine out of plywood/hardwood and lots of glue. Use
the same thickness you want the engine/cylinder walls to be. If its
water cooled, leave a cavity betweeen the cylinder and outer block.
Cut out any 'cast in place' holes and glue on any bracing or 'spuds'
for mounting bolt holes. Then bandsaw it apart at the corners
(like a productuion engine was - look for the parting lines). From
this you create your pattern and then the mold.

I'd be interested to see where you are going with this.

Pete

wrote:

I have a few questions and one assumes you have casting experience
and a well equiped machine shop suitable for engine work:
--Yup.

1- What material will you cast into the mold? Iron, alumninum, what?
Because you will want to get the correct 'shrink' rule to start making
the pattern pieces. This is mostly important if you plan to use
existing parts like pistons, crank, cam.
--I'd like to do it in iron, but I'll settle for aluminum if I
can't find a good small iron foundry. Have done aluminum at home, but
would prefer, in this instance, to farm it out to a pro shop.

2- Is the engine liquid cooled?
--It's a steam engine; single-acting poppet valve variety; no
cooling channels required. If anything I want it to run hot.

An easy visualization would be to look at an existing block and trace
the parting lines. This will give you an idea of how many sections
were used to cast the part. Pay attention to the position of the
steel plugs (blow, frost, heater hole, core, pick a name). These are
the core pattern suspension holes.
....

The real tricky part is in the "one off" machining to accomodate
existing crank, pistons, rods, covers, etc. Not trying to discourage
you, but you will be developing this one casting and recasting it many
times to get it mostly right.
--Yeah, I kinda figured. Da plan is to make it work, then maybe
make a few spares, as I suspect I'll be beating these things to death..

Try making the engine out of plywood/hardwood and lots of glue. Use
the same thickness you want the engine/cylinder walls to be. If its
water cooled, leave a cavity betweeen the cylinder and outer block.
Cut out any 'cast in place' holes and glue on any bracing or 'spuds'
for mounting bolt holes. Then bandsaw it apart at the corners
(like a productuion engine was - look for the parting lines). From
this you create your pattern and then the mold.
--Yeah, I guess. Cylinders I understand but the crankcase still
eludes me..

I'd be interested to see where you are going with this.
--Sorta like the old Stones song about the guy who's still
inventing ways of making sealing wax; I'm wanting to build the fastest
steamboat in the world. The record is one of the lowest on the books.
A pal in Australia has the fastest steamboat currently floating; he did
around 35mph about a decade ago. Rumor has it there's a team in Italy
working on a boat. I'm just another crackpot with a dream, heh.

--
"Steamboat Ed" Haas : Whatever happened
Hacking the Trailing Edge! : to Tom Nelson?
http://www.nmpproducts.com/intro.htm
---Decks a-wash in a sea of words---

"steamer" wrote in message
...
--Got a situation where I need to cast a small 3-cylinder engine
block. Trouble is, altho I have drawings for the engine I'm damned if I
can
visualize what the patterns need to look like, to do the crankcase, etc.
Would like to chat with anyone skilled in this, particularly if they live
around the San Francisco Bay Area..
--Thanks,

--


The application is way above my pay grade - but when I design cast parts my
best resource is my casting shop. Usually I can just draw what I want my
rough cast part to look like and they design the molds using techniques that
they are used to using. I suggest you select one or more casting shops
first, pick their brains as much as they will allow, then design your parts.
Be prepared to adjust your design to fit their requirements, probably
multiple times. They will design and build the molds. Who actually owns
the mold is a point of negotiation.
--
********
Bill Pounds
http://www.billpounds.com

2- Is the engine liquid cooled?
--It's a steam engine; single-acting poppet valve variety; no
cooling channels required. If anything I want it to run hot.

This would have been useful to know up front. (grin) If it helps to
think in terms of the crankcase layout, first get the crank mocked up
(out of wood is still good - assumes you don't have one) . Then cut
out a large enuff hole in another piece of wood, split that in two to
get two half circles, and bolt it back to gether around the crank. Do
the same with your method of moving the valves and add that to the
'crankcase'. Now box in the 'crankcase'.

It occurs to me that steam engines leak past the piston seals quite
badly (also not a big deal most of the time). If you intend to run
the crank in oil and the crankcase is attached to the cylinder walls,
can you calculate how long the engine will run before seizing up from
the ensuing oil/water sludge?

Pete