Hi everyone. First off, I'd like to say that I'm a third year mechanical engineering student and I've been thinking about some things they don't teach us at school. My first area of concern is how the cores for the water jackets are set up in the mold. I understand the basics of sand casting but never looked at anything with hollow parts. The other part I'm wondering about is once you have the cast head how do you find a zero for machining everything? The reason I'm asking this is because I'm interested in running an engine that has no aftermarket support whatsoever. If this thing had a better set of heads it would have so much more potential. Any help is appreciated. Thanks, Nick
Get some of your ME buddy's together and head down to the Mack Trucks Engine Foundry in Hagerstown, MD. I am sure they would be more then willing to give a bunch of ME students a nice tour.
Contact Bob Walla. He makes nice aluminum 409 heads. Just google him and 409 to get his website. Nice guy.
Hey, Nick; The inside cores are usually "green sand", set hard w/ CO2. & you have to have the outside cores on the plates for the boxes, too. There are lots of ways to do one-offs, but a little experimentation would be nice. A good source for neat old books/info is: http://www.lindsaybks.com/prod/index.html & I think the US Navy Foundry Manual would help. I have it, but not sure where it is. I think it has green sand techniques. If I can find it, I'll check, but you could call Lindsey & ask. I'm curious: what mill, & what type of head (complexity?) ? Marcus...
www.409raceparts.com Here is the Bob Walla 409 site mentioned above, look in the photo section for some cool pics...
follow the parting line on castings to where ever there is an opening. notice that the opening is usually split exactly in half by the parting line. that is where legs of the core passs into pockets in the mold halves and support the core in position. So called "freeze plug" holes are actually more for supports for the water jacket core than freezing. You hear about blocks unable to be bored because the cylinder wall is thin on one side due to "core shift" thats when the core moves within the mold before or duiing the metal pour.
Thanks for the help everybody. I'm going to see if I could get the ASME club to take a trip down to that casting plant. Sounds like it would be really interesting. I'd like to eventually make a head for the big GMC V6 engines. The exhaust port is extremely restrictive as it necks down so much after the valve that i cant even get my finger between the top and bottom of the port. And the chambers are absolutely horrible lol. They are huge and shroud the valves a lot. Hopefully with a smaller chamber it would be possible to get the compression up from 7.5:1 to around 10:1. They have some decent potential if they had new heads I believe. There's a guy on the 60-66 GMC group that built a 522 out of a 478 block. And they just look really cool too which is a big plus. And later on I think it would be really cool to make a set of hemi heads for my tall deck 371 olds too.
Your ME class that covers manufacturing topics should cover casting processes and explain how cored parts are made. Might even do it in the associated lab (my coursework included sand casting lab sessions). Would be a core part of a ME program.
Might want to check with AFS ,American Foundry Society. They should be able to supply you with all kinds of info.
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