Thanks. That is good idea I think. Ok No oilite. By chamfering the oil hole on the outside I would also get a bit of a register. I could also mount washers in the shaft with the rockers which would prevent any movement should it happen. Pressed in stuff in aluminum is usually 2 1/2 times tighter then in cast iron. When i worked in the machine shop business I used to get all the exotic stuff to fix (Lotus, Mercedes Jaguar and so on.) Often I had to install seats. With adjustable cutters you could set them up and reset the bore size. With non adjustables you had to wait until the "owner / tyrant" left for lunch and then get creative and hide them. If you hold to the right interference fit there is usually no trouble. Seats I also made a tool to swage a slight flange over and buried them just below surface. never ever had one escape so I am ok with that. No one else in the shop wanted to do them. Nobody bothered you though when you were working on them. We also used to rebuild a lot of VW heads (air cooled) I would get them back from the local foundry who welded up the destroyed heads as he was an expert with aluminum and then I would get the job of carving them all back out to original. i enjoyed this work as a young fellow and if the boss or i should say owner hadnt been such a tyrant I probably would have stayed there forever. My machine shop boss was a great guy but his dad the owner was a horses patoot. He biggest form of excersise which he practiced every moment of the day was jumping to conclusions while having no knowledge of the facts. Don
I have managed to make a tool to punch holes in the styro the ID required with no bushing. i already discovered how to core round holes with a metal core by cutting it down one side, inserting it then fill it with sand. After the pour use a set of pliers to squeeze it and remove. It works well and leaves a smooth hole. I did that several times when making my hubcaps. I have punched out enuf for 12 rockers. I am also revising the design a bit. I checked with my pal at the other shop. He still has a rocker arm jig for my old Souix valve grinder kicking around. So now I can properly radius the wear point. I will work this in when I need a change. Don
First I traced the old first casting. Then I redesigned slightly. Next I punched out all the holes in the stryo (24 halves make 12 rockers) Next I cut out the pattern and traced it onto the styro 2 for each rocker. One half has the holes located , one does not. I can locate them all the same this way and after gluing together perfect them a bit more. I am going take my time cutting and shaping. I am also going to sift the sand finer to see if it improves the castings. It is too cold for shop work today anyway so I am inside keeping warm. I am glad I am the first one in my family to attend Kindergarten. Used all the skills I learned there on this one. Who knew it would lead to stuff like this. Don
Chopped down to managable size. I think it is time to make a hot wire cutter. I have the dimmer control, the guitar string. I need to find a 12v transformer in my Ham junk box . Don
I'v been watching this from the begining, very cool !! I Just finished up building a melting furnace last weekend, burns propane / waste oil I can't belive how much hotter the oil burns than propane. Now I just have to make some molds / patterns. Years ago built model planes with styrofoam using a hotwire cutter, used the wire out of a old toaster and a battery charger, as I recall the frame for the wire had to be spring loaded to keep the wire tight due to thermal expansion. You could stack up all your patterns on a peice of round stock cut out two wood templates one for each end and cut them all at once with the hotwire that way they would all come out identical, thats how I used to cut the plane wings. Been lurking aroud backyardmetalcasting.com lot of cool info, looks like you can use small amounts of wax to fill voids in your foam, also some guys are coating the foam with thin coat of drywall mud and allowing it to dry before placing in sand for a better surface finish. Good luck and keep up the good work and thanks for sharing.
Thanks. As you now know this is a very fascinating deal. My first attemps at casting about 8 years ago were a disaster. Then i threw the book away and fooled around till I got the results I wanted. Now I am having a ball. My burner works in afterburner mode. I didnt plan it . It just does. I light it and the propane torch sound is quite normal for about 3 to 5 minutes. Then there is a whoomp and the unburned gases light and stay burning. It sounds then like the roar of a small jet. It doesnt waste much time melting in that mode. As short as a pot in 7 minutes. 12 is about normal though. I may make a short video of it from light up to afterburner mode. Even though I know it is coming I often jump when it switches mode. I just love fire smoke and noise I think. The little boy in this old body obviously aint dead yet. My pots are made from a buddys busted 64 Chevelle driveshaft. Sized to provide just enough for more than one piston. Budd I am using my flasks now for the styro stuff. They work well. Although I dont need two . (cope and drag) Just pack and pour. Don
I know I was gonna build a hot wire cutter but in this cold snap I was working at one of my inside hobbies (fiddle making) and saw my rocker styro patterns sitting there. I put down the fiddle and grabbed one using the same knife. A few minutes later out popped a good rocker half. I am just going to work away at these this way for relaxation. Same skills but for making a different kind of music! ;>) (zoom zoom )What can it hurt? Don
I had that same question a few time when I made my over head for my model A engine. If you have to ask you probably will never get it. It is some thing inside that makes us do it, especially if some one says it wont work. My engines runs fine I could not be prouder. Way to go Dolmetsch
I couldnt have said it better George. It was you BTW making that head that got me back off my **** and back into the game. Thank you! Don
<TABLE cl***=tborder id=post5955593 cellSpacing=0 cellPadding=6 width="100%" align=center border=0><TBODY><TR vAlign=top><TD cl***=alt2 style="BORDER-RIGHT: #e5e5e5 1px solid; BORDER-TOP: #e5e5e5 0px solid; BORDER-LEFT: #e5e5e5 1px solid; BORDER-BOTTOM: #e5e5e5 0px solid" width=175> </TD><TD cl***=alt1 id=td_post_5955593 style="BORDER-RIGHT: #e5e5e5 1px solid"><!-- icon and ***le --> Re: Casting Pistons <HR style="COLOR: #e5e5e5; BACKGROUND-COLOR: #e5e5e5" SIZE=1><!-- / icon and ***le --><!-- message -->if you get board you can widdle me out some aluminum rockers for my 276 desoto hemi. Why Budd? Do you have a broken hand? Nothin stopping you from doing it. BTW I have a step brother / cousin living on your island. Sells Body shop stuff or abrasives I think. Don </TD></TR></TBODY></TABLE>
Hey Don, if you're looking for a 12v power supply for a hot wire set up you can find them in pretty much any old radio or computer. I tear the transformers out of radios all the time they are usually 12v, computer power supplies work even better as they out put 5v, 12v, 3.3v, and you can get up to 17v as well. That's what i use for bench testing things, very versatile, and you can usually score an old computer tower for free. The computer power supplies require a bit of rewiring to be used, but I think you can handle it.
I actually found two in my Ham radio stuff (VE3LYX) down stairs. However the rockers are all cut out. Took about 4 minutes each so maybe next time. I reasoned that it would take me longer to make the hot wire cutter than to cut them with my tools i use for making fiddles. Now that i have finished i agree with my original presumtion. Thanks Don
No I made 16 and decided that was a wonderful experience. I wouldnt have misssed it for anything but I have other things to do. As my health starts to deterioate with age and abuse I realize I have maybe only a year or two left to race my dragster so I have decided to do the best with it I can. By that I mean as it is. Cash is low and time is fleating. I intend to make the most of it. Still it was an absolutley wonderful adventure. I would now make anything I needed. I kept everthing Don
Funny thing when learn how to do things and get the time to do it, then we are to old to get it done. Great job on those piston Don, maybe some of the younger guys will try to make instead of buying every thing already done.
Yeah! I must tell you it was and is high on my lifes adventure list. I wouldnt have missed it for anything! Don
Well I have welded up many damaged pistons and they have been used in race engines and stock. I wish you had time to finish ur project!
The Jalopy Journal
