from the Egge video posted at the top of the page, it looks 3 piece to me. looks like a flat "blade" in the middle with the two wedge shape pieces that go on either side. pop slide out the center and it allows the two wedge pieces to slide out. I could very well be mis-viewing the video though.
NO All the parts we have made are tougher than nails. Using old pistons which may have the right mix. I have pryed on, beat, dropped, and pounded this piston and there is barely a mark on it. It is my understanding that the pocess known as "Chilling" is responsible for that as the aluminum cools very quicky in the mold surface and is very dense. You can not scatch is almost it is that hard. I saw the device in the video. I would rather not get that complicated unless I was making hundreds. I am going out now as I live on a small farm and I know where there is some very unusual sand. I am going to dig some up a see what it is like. Man this is interesting for me. Thanks everyone for chipping in. I am out on a limb here but that is where I love to be. Maybe I aint dead yet! Don
don, the three piece setup looks EXTREMELY easy to make imo. piece of whatever thickness flat stock you need with two thicknesses on either side. drill two holes to bolt them together outside the mold then attach it all. although, I work in a machine shop. I'd just have one of the guys draw it up for me and whittle away out of billet.
Good luck to you, sir. I'd like to do this too. What is the "chilling" process that your talking about?
Apparently when hot molten aluminum hits a cold steel mold right at that point there is a quick cooling that makes it harder there. One book I have even suggests if you have an area that need to be hard put chill plates (Steel Plates) in your mold. I am no expert (yet) but I am learning as i go. I spent the afternoon making ingots in a small size muffin tin from used pistons. While i waited for the melt I dug up a bucket of the sand I remembered seeing on the farm here. I sifted it by hand. It is a lot better then what I made . I can squeeze it in my hand and it holds the shape . i can even see the lines in my hand in it. I did a couple of impressions in it with an old Dodge Brothers bearing cover. It looks very very good and did not fall apart. BUT I am casting at least the first 6 in steel. I will now though be able to make a good core from my Ameliasburgh Sand. Don
I agree with you BadgeZ28. Dolmetsch I,m sure you are an excellent machinist and obviously a very intellegent individual, but I also cannot understand why you would attempt to make a cast racing piston which will probably cost more and be inferior in quality to a forged racing piston which you can buy over the counter. I admire your undertaking but being a hotrodder I would spend my money and time building something that would add to the perfomance of the slant 6 such as a good intake or crossflow head.
Give him a freakin break! He is retired and CAN do it just the same as he is with his slant 6 tunnel ram. Some times a person just needs to do something to see if he can. Take my flintlock for example, sure a new .30-06 is cheaper and more efficient and I could buy it off the shelf but instead I carved a smokepole out of maple and assembled the spark making rock lock thingy from raw castings................
"time building something that would add to the perfomance of the slant 6 such as a good intake or crossflow head. " Well in the first place the cylinder head is not the problem. Cylinder heads are something I know a bit about. A slant six can be ported to +200 CFM with several porters making 220 cfm (@25"H20) That is more than enough to support 440 HP and yet we are not there. I really really really question the idea that making a crossflow head is somehow the answer to anything. Other than perhaps a bit of heat generated by the exhaust coming out between the intake (and the head is water cooled or warmed anyway ) I doubt very much if the air really knows it is coming back out the same way it went in. I know it looks nice and V8s are that way but that is incidental to that. I know Dr D and all the gurus at some website will disagree. Frankly Scalet, I don't ---- - ----. Air flow is not understood very well. A few days with you own flowbench will teach you many things you dont want to learn. Much of the problem with the slant 6 stems from its huge stroke, 4.12 and its tiny 3.4 bore. Camshafts are not really designed for such set ups. IE if this was a small block chevy with a 4 inch bore the stroke would be 4.847 inches. With the popular cams we have for these chevy engines today this engine (4 inch bore and 4.847 inch stroke) would run like crap. Do i think anyone actually sat down and designed a cam for this (225 slant six)set up? No i dont. I know they have sorted through some lobe libraries to find which worked best but most cams are designed and tested on a SB Chev . Only recently have the big cam companies even served the Mopar 904 lifters high rate ability. I am quite sure they have never sat down with a slant six and designed a cam specificaly for it or any other engine with such a long stroke vrs bore ratio. I have a cam now I had custom made but I am just beginning to explore what this engine wants. So why make the piston? Because I enjoy learning how to do things. It has nothing to do with cost or whatever. It is a learning experience. As I age and my health begins to fail I derive great joy from things like this. If you visted my website you would see it is my hobby exploring stuff for the fun of it. When i am in "the home" with dibble on my chin I will look over at my old pal Vern and say "Remember the days we cast those pistons?" Vern will break into one of his characteristic big grins , cross and uncross his 6.7 frame and say (I guarantee it!) "Don't remind me!" And that my friend will be worth a million dollars. As for intake for the / I am doing my part so far. Don As for cost of this project? So far $22.95 for propane. All the rest was free or we had it anyway.
I can't help but add an unneeded response to Areorocket. You seem to be missing the entire motivation behind a Hobby. Buy a new Toyota and you can save all that time wasted on unnecessary fabrication watching TV. But if you like fabrication more than TV, what should you do?
If you are going to use a sand mold, use "Talcum Powder" as the release agent... Don't go and purchase that fancy stuff from a casting supply company, it is nothing more than Talcum Powder.... I have cast a few items out of aluminium....
I always thought that the main reason for cross-flow heads on an inline is that there ended up being more area so the ports could be made much bigger. I agree that the air doesn't care which way it comes in and goes out, but it probably likes the extra room to move around in.
Here on the HAMB we have Don casting pistons, another individual making a performance head for a model T from scratch, many who have scratchbuilt intakes, headers, and back when a guy tried making his own cell-type radiators. I submit that this is the best audience for iconclastic backroom engineers. I never know what might be next. This is the place to be if you want to learn.
To bad you weren't closer. You too could be on on this great adventure. It is only an hour away though. Thanks for the tip. (My wife casts or molds chocolate. i have no idea why. She can buy the finished product cheaper in the store). She has been a source of little things and tricks she has learned doing that. So far everything she has suggested turned out to be good info. Some of which I had to learn the hard way. Now i listen up. The first piston is not that bad. I believe the second will be better. Once I am on a roll i'll do the other five and a spare or two. I know it doesnt look like much but it is what pistons start out as before they get machined. This is a cast blank. It is enough for me anyway. Once I set the lathe up I can cut the diameter and face the head with the same operation on that lathe. It can cut from both sides and I just need to set three stops. If a head was a Hemi or a pentroof then a crossflow is the natural way to do it. A bath tub or a wedge chamber ? Probably not much if any difference in my opinion.
you mention in post 58 about heating the mold. I was going to ask you about this earlier. I would think that a preheat for the first of the run would be the way to get a consistant result. Although it might be ok to just use the first casting as the heater upper and send that one back to the pot. This is if you are going to be able to run them as a batch. I guess if they come out of the mold ok you could do that. This is a great project you got going here!! Are you going to offset the piston pin? I've found even a small amount (as little as .030 in.) to be a power benefit from a centered pin. Frank
I have thought about it. I havent yet decided. I figured I would get 6 or 7 good blanks and true them up on the lathe then decide on the pin. Here is the whole skinny. I want to use a 170 block and a 198 crank. I know they say you cant but I sometimes dont get it. There has to be a way to make it fit. I e machine counterweights down etc. The pans are the same , the bearings are the same I am hoping it can be done. I have a 170 engine in the back of the truck and am tearing it down today. With the difference in stroke if I can do it the pistons will be out of the hole quite a bit as the 170 is a zero decked engine or close. If I use the 170 rods I need a piston with a raised pin height or shorter compression distance if you will. I plan to make them which is why I am doing this right now. It is very difficult to get even a custom manufacturer to make stuff like this. I had a set of pistons made for a 300 Ford and they came .070 higher than I speced them . The manufacturer said he thought I had made a mistake in my specs and so he made them that way. (like stockers) I was able to do a bit of maching and work around it but it was a pain and there was no return once it was paid for. So i will make this set . If I like it I will probably get a set of super duper forged copys made. Why this combo? It gets away from the 4.12 stroke and gets it back in the land of the living. The 225 block I have now in the rail is 1962. I have bored it 160 odd thou and it is still thick enough. I checked a 79 block and it will barely take 080" so I am hoping the early stuff is why it is thicker. This 170 is 1961 valiant. If I can go with a 3.5 bore or better and use the 198 crank then I can turn this thing to 6500-7000 safely and it will respond to a conventional cam design since it is not rediculously over square but almost square. Ideally i would like the stroke 90% of bore but if I can get closer than I am now I will have a different engine I am sure. I built and raced a 198 in the sevenites. or my wife raced it as you can see from the foto it was successful. It was in a 66 cuda but I bought the car with no motor and bought a NOS 198 block assembly from Minakers in Milford. I will warm the mold next time. I believe you are right. I have also come up with an idea for a collapsable core. Don
interesting that you found some high quality sand. Doesn't molding sand have something else added to it to hold it together??? I've read a little about the process of sand casting and that seems to stick out in my mind. damp sand is very bad as well. maybe I should go hunt down that article I read.....
Molding sand uses either water or oil to hold the sand together. Often other additives are added to the sand, ie: clay, in order for the sand to keep from breaking apart. The sand must hold its shape. A quick test is to squeeze the sand in your hand, without any moisture being squeezed out, while retaining the shape of your hand.... I believe it is in India, where they pour directly into sand on a beach.... I remember seeing a picture of this on the net when I was researching DIY sand casting a couple of years ago... Wow....
I don't think I would like pouring into or onto wet sand or wet anything. Might find the pour coming back at you. I have poured aluminum into several heat riser ports in heads to isolate the center two exhaust ports on Chryslers. One time, for some reason the heads owner spayed WD 40 into the port. Big, hot bubble when that oil boiled. No good.
I agree- pouring something that's hotter than water's boiling point into a wet mold will turn that water into a gas that expands rapidly... not good at all.
heres an interesting video of exploding aluminum, http://www.youtube.com/watch?v=A796N_YZTm8&feature=player_embedded i remember back 30 some years ago i worked in a shop that cast aluminum survey markers, we would pour about 100lbs every other day, or every three days, the pot was all one piece and had to be tilted when you poured into the hand held pot, two people were needed to do the pour, that second pot was cast iron and had to be heated with a tiger torch or it would pop. the guy who was my boss and ran the foundry learned his trade at the place in my home town of Bridgewater NS, long gone now, i should of tried to learn more for him. http://www.oldmarineengine.com/history/Acadia/Acadia.htm
This sand is not wet but not dry. It must have some clay in it because like the Candy man says you can squeeze it in your hand and it holds the shape. You can break it off in chunks afterwards but your hand is not wet. I read that it occurs sometimes natuarally. Casting in the sand is normal thousands of years ago. Huran was the guy who cast the stuff for the temple and yes I did look that up in the big black book and read it over several times as well. What got me thinking about our sand was a sand pile of local sand just down the road at a township site. It had a loader tire track in it very distinct. We had several hard rain storms and rainy days and each day i drove down and looked to see if the impression was gone. It is still there good as ever. I thought I have sand here on the farm and I know exactly where it is so I grabbed my shovel and dug a pail up. It is fabulous stuff although I spent all that afternoon putting it through a flour seive. It is much better natural than my homemade oil bound sand. I know about pouring into wet and I once tried pouring into a home made plaster of paris mold (unfired) and got the big bang. Luckily I was only making an emblem so there wasnt much aluminum around. Now I am more careful. I got the metal core out of the piston today and have started to work on a collapsable core. I weighed the piston blank afterwards. It was 674 grams . I will lose probably 100 in machining. I also chucked it in the lathe. It is remarkably true for being a rough cast core. Not much over .020" runout so probably .030. would clean it well. It has a diameter if 3.540 " I would like a finished size of around 3.5" so If I am careful it will work. I can also see inside the piston the cold section of the pour. Preheating the mold hopefully will take care of that. Don
Well guess the mold maker who gave me a few lessons was wrong using a "oil based molding sand" or "water based molding sand" for "sand casting". Oh well..... One has to remember, the molding sand is only damp with moisture, you cannot squeeze out any moisture from the sand... Research DYI sand casting on the internet, you may just be surprised....
Simply amazing. Now you (and I )have to throw away all those parts already cast because it can.t be done. There is nothing to say here is there? Don
wow.. must have been doing it wrong. Both when I did some of this for research (yes they even gave me some papers saying I know what I'm doing) and now that I'm doing it at home. Casting is done with a "green sand" a mixture of sand, bentonite clay, water and sometimes oil (not needed). The water helps the clay stick and keeps the mold in shape. Yes, you need to be careful, but with the right sand mixture you can make some great castings. Don, have you considered just sandcasting your pistons? from what I've researched it's an easier method because the heat and gasses escape so much easier from the mold through the porous sand then it does through the metal casting die where you have to allow for gas escaping or you may get gas inclusion. On the tempering part of it, see if you have a extrusion company close by (you'd be surprised how many there are) they should have a huge tempering oven and may be able to let your pistons hitch a ride. I know I helped several home tinkerers in the past when I did extrusion tempering.
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