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