if you are not already a member, go to www.vwdiesel.net/forum and look up my thread on this subject. I am trying to gain interest on getting some heads made in either China or Vietnam. In order to offset the cost, I need as much interest as humanly possible. Please DO NOT! PM ME HERE! look me up on www.vwdiesel.net/forum and find my thread on this subject. If there is an adventageous individual out there that would like to attempt this here in the states then more power to you, I would love to do it here, but have found no one that has the capabilities to make cast heads anymore, and I would love to hear from you.
I believe the aluminum head castings on those things don't have the stiffness to keep a head gasket in them when the boost pressures get up there. That said, a low volume cylinder head casting- probably won't ever happen, or if it does, it will cost $$$.
If it's just for drag / dyno, or if you are very determined, consider just working from billet. The cost will still be in the thousands per head but at least the tooling won't run well into 5 figures.
Purchasing from overseas is always a big gamble unless you have built a business relationship with somebody. That said, I wouldn't recommend using other people's money to fund a hail mary attempt to cast parts overseas. If they show up stateside and are garbage, you will be up a creek w/o paddle.
So, again, I'd consider billet. If you do a little research and consider the stiffness of the material, rather then the strength, you'll also find that 4340 is not a wise choice. There are other steels which are cheaper and machine easier, and will work every bit as well.
picked 4340 because of thermal expansion issues, this isn't a pipe dream here folks, i really am doing this, and I am not giving up. I want it, I need it, I am not doing full drag, i am simply building a bullet preoof engine. I am going for about 40+ psi using a custom 17/22 vnt garrett turbo that has a very unique activation setup that is all mechanically controlled. I am sending the pump to Jedi Master Giles and running some very high profile internals. All that is left is building a head that withstand the punishment that will ultimately be unleashed upon it.
Almost all steel alloys are about 50% of the thermal expansion of aluminum. Once you've switched to a carbon steel alloy it's all basically in that ballpark.
Even 1018 versus 4340 is only like a few percent different- both are roughly half of A356, just to pick an extreme example.
Personally, I think if the OE headgasket will survive the difference in expansion of the block, versus the aluminum head- It won't care what the heck steel head you put on there. It just needs something that won't bow up under the cylinder pressure.
I like reading pipe dream threads, so I decided to look it up.
Yeah...where exactly is it? It doesn't seem to be very popular, cause it's not anywhere near the top of any forum viewable by those of us who don't register.
no pipe dreams here, this is real, and even if it isn't I will get it by my hands.
Interesting. If it gets done, then there could be a market for a LOT more than just a hot diesel head...considering the 8v gasser head is 75% similar.
I thought the same thing, however the dynamics of the internal combustion of gasoline vs the sheer violence of combustion in a diesel would make the heads used for diesel much easier to melt under boost. if there truly is a demand for them then perhaps this will get the numbers necessarry to offset the cost of R&D and give a cheap total turnaround cost. The only thing would be to decide which head to use, I would need maps or a junk head to send them, and sheer numbers
4340 for a cylinder head? Are you for real????.... ....I suggest you look up all about metal before making any daft decisions. There is plenty of aluminium alloys out there that will do you. The 7 series or the 2 series I would be looking at.
Thermal conductivity of aluminium is not to be sneezed at and it is this which will transfer the chamber heat to your waterways.
Ill also go onto say that a billet head is a bad idea because of tool access to the waterways above c.chamber. You could possibly use heat pipes as used in the plastics moulding industry to cool any hot spots which you_will_have going the billet route.
Ive been through head design a million times with billet which is why Im casting mine. Seriously, talk to someone that knows whats involved. Pm me if you wish.
Last edited by Brian.G; 07-12-2010 at 10:34 AM.
You do realize that this is for an OLD SKOOL IDI, "that is indirect injection diesel, for the uneducated" head? what that means is that it is not direct injection, the mechanical pump sends the fuel to the mech injectors which inject into the swirl chamber "which is part of the combustion chamber in cc's of vol." fast moving intake charge and slow moving expended exhaust "this generates a lot of heat locally" under boost of the levels that I will be doing 40+ psi I will inevitably melt my pistons and head, which as I am sure that you are aware is a BAD THING, hence the need for a stronger more resillient material to withstand the boost pressures and heat soak under durations of boosted acceleration. Please don't make any attempts to crush my dream, it is certainly a bad Idea, a lesser motivated pipe dreamer would likely be deterred by your smart sounding words, but I have talked to the pro's about this and have made my descision and WILL move forward regardless of scepticism of haters or sceptics.
thanks you for your concern,
Cpl Kevin A. Davies, USMC
Im not out to crush your dream, and I know a lot about heads, but thanks for the info all the same.
Do you know whats involved in milling coolant ways internally inside a head? I really dont think you do.
I suggest you talk to a machinist and a metallurgist as soon as you can.
Then get a ballpark price, then thermally and mechanically test it(takes a long time, remember youll be selling these to work perfect for a long time) Maybe hire an engineer if you dont feel confident to sign it all off yourself.
After doing, and paying for all that decide on a final price(which will be hard as the more you buy, the less they will cost, but how may do you forecast will actually sell when it comes down to it? Sell as in sell, not as in ''Im interested'')
Best of luck with your 'dream'.
(And by the way @ BS4, you cant make a petrol head from steel, or cast, and run high cr, the metal simply cant transfer the heat quick enough to the water, you will get hotspots, and thus detonation) This is the reason modern cars can run higher cr that the old iron headed cars.)
A few ihi cutaways showing port jacket and swirl chamber location,
Last edited by Brian.G; 07-12-2010 at 05:22 PM.
The new metal heads will be cast, in other words the water passageways will likely be molded by foam and melted out when the cast is poured. I do not plan on having the thing cnc machined, although, it was proposed as an option by a couple of machinists that I consulted. The finishing will be machined, such as the valve seats, swirl chamber area and the cam journals "you know, the common machined surfaces" I have a junk head "AAZ engine code" to rape for numbers mapping etc. I would do it myself, but lack the time and resources to do so. I am active duty and going to Afghan soon and want to see this through to fruition, I cannot do it alone, which is why I am asking for help. I know all of the information you have said, and appreciate your candor. I would love to make a forge in my backyard and experiment myself, but I live in base housing, and as of yet there are no rules on having a forge on your property, I do believed that such things are likely severely frowned upon. Oh, I am a member of the Team kai hei tai on battleofthebuilds.com we are going to recieve our car on the 22, and still need to find a toyota turbo diesel and hilux frame to complete our project. I have a lot on my plate I know, I'm crazy, but I like it that way.
For one thing, it would be a foundry, not a forging plant. Two, you DO NOT NEED the high tensile strength of 4340. If you get anywhere NEAR the strength limit of the material, you'll have long past blown your headgasket. I don't think you understand- almost all steels have close to the same stiffness, and it's stiffness you need to keep the thing from bowing, NOT TENSILE STRENGTH.
Basically, stiffness is how hard it is to bend, strength is how far you can bend it before it breaks, or stays permanently bent. You won't come anywhere near the yield point, so who cares what that number is.
So, say your head is made of 1018 (or some other cheaper steel) and heat treated to rockwell 30 C. The stress levels go to 30 ksi- The ehad will hae bowed some arbitrary number, for example, .001", between the head studs.
Go make it out of 4340, heat treat it to rockwell 30c- you'll get *roughly* that same .001" bow between the head studs. What's the point!
And, he is right about the cooling- it will get locallized hot spots. You could try to combat that by making the wall thickness thinner in critical places, to increase the heat transfer- but you'd really be playing with fire there unless you had some serious engineering and design software to work on it.
I'd call it a drag car, and make a billet / non water cooled or with very simple water jackets- head, with direct injection. It'd be easy to drill / tap ports for direct injection, much more so then indirect. Then you can make a run of just a few, or 10, or whatever.
It'd be more important to get something that isn't going to warp to hell as it ages and heat cycles, then something cold worked and heat treated to meticulous strength levels.
Pick a steel that's not too gummy and machines well in an annealed / normalized state.
A casting will be a $100k project, and you'd need to sell hundreds of heads to pay for it... assuming you don't get $40k worth of bad parts from overseas on the first batch and bury your project for real.
We aren't trying to rain on your parade, we just do this for a living. I'd love to cast a a 16v "1.8t" head as well, but the economics just don't work, and that market is WAY bigger then an indirect injection diesel head.
I guess that settles it then, I'll do it. Don't get me wrong, I have talked to plenty of folks who said that it can be done, but it was a matter of more or less will they do it. I'll take Chinese cheapo engineering over good old fashioned American ingenuity "am I really saying this???" I would rather watch it crash and burn somewhere in the west before I never see it through to fruition because of a rediculous pricetag and pure fear. Like guys who never drive their cars because they don't want the value to go down, to me that is like not having sex with your G/F, Wife "you pick" so she will be more appealing to the next guy. I say damn the torpedoes full speed ahead, do it and if it doesn't work I will have an excellent engineered example of one that doesn't work, and I can move from there. WITHOUT RISK THERE WILL BE NO PROGRESS! I am betting it all, I don't know if it willl pay off, and frankly I don't care, I know what my goal is, I came here for help and I got some, thanks to god and everyone. There are no sure bets in life, and fate rarely chooses a time of convenience. I will continue to do the necessary research, because I don't want this to fail because of stupidity, but if you don't want to help or you are expecting a CPL in the USMC, "a public servant I might add" to give up so esily you are sorely mistaken. I don't have that kind of pay , but I will overcome, I must.
yours always, and Semper FI,
Cpl Kevin A. Davies, USMC
Last edited by NintendoKD; 07-13-2010 at 12:38 AM. Reason: additional information
I will agree that the use of high dollar steel is not needed for the head of an IDI diesel, plain old cast iron would probably be fine, I will say that the heat transfer issue is not an issue.
the diesel does not suffer from pre ignition like a gasser, so the hot spots are not such a big deal, as long as the head does not get too hot and melt in those spots(unlikely) it will be fine. also the flat design of the head(no hard edges, and the ones that exist are made of inconel) the hot spots will be minimized anyway.
heat transfer away from the prechamber is one of the things that make the IDI less efficient than its DI counterparts, so the lower thermal transfer of the iron would help us make more power, burn less fuel, and start easer when cold.
I wonder if one of the companies already casting new heads from aluminum would be able to cast a limited run of iron ones for us much cheaper than getting them made from scratch.
YEAH! shrink rate .... I said it first though....... just couldn't remember the name "dman memory" LOL The thing here is I want help getting this done If I can do it in the good ole US of A I want to, but I really cannot wait much longer. I may die in Afghan, and no one will carry on my legacy
Fwiw, if you get bad enough localized heating in cast iron, it'll more then likely cause cracking in that region given some time. Cast iron is not very forgiving in that regard.
I guess I'm sort of struggling with why one would want to cast a more complicated IDI head, to a simpler direct injected casting- which will make more power. It will be cheaper, and all the know-how is already available off the shelf in the form of TDI parts. Even if you want to still go ahead with a steel or iron head.
I suppose if the moulds or forms were done though, it might not be too difficult to re-cast some in aluminum? The only real reason I'd think it's a good idea would be to replicate the eurospec huge port/valve heads without having to go through the effort of porting and polishing everything.
Ok, so cast iron will crack and be hard to weld, 4340 is out because it is too rigid and hard to Machine. An engineer that I talked to suggested 4340 because of resiliance and thermal properties, so under 40+ psi of boost in a small engine what would be the best material to cast the head in, and to clarify, yes, we need waterpassages. what do the cummins guys use that run XXX boost numbers "not really, but you get the idea" I understand that their rigs are directly injected with vgt turbos and computer controlled everything, and I am running an IDI with a mech pump mech controlled VNT with like three wires to the whole engine but there has got to be something to this. As I understand it the IDI thing was given up due to lack of new technology/materials in the field we have space age ceramics, and different materials as well as computer designed swirl chamber ability, also as I understand it the IDI is more efficient and produces less pollutants than it's TDI counterparts up until here fairly recently. I am shoving this and a custom driveline into a 2001 MR2 Spyder, and am kind of doing something that has only been really attempted by the finns "love and hate both come to mind" I want to one up them and stretch the abilities of this engine to it's limits, and to do that the key component is going to be this head. Shoot, couldn't we make the whole thing from ceramic?
I forgot to say, Ive spent 4 yrs on r+d for my head(the one Ill be casting myself) This entailed reading every night for 3-4 hrs, 7 days a week, buying a book on metallurgy which cost me 443euro, and doing countless tests upon tests upon tests.........
Have you the money to pay for someone to do all this for you? A casting company is just that, they cast stuff.
You still have to figure out if it will work off the drawings, make patterns, plan the machining, know what to leave on the casts for machining, the shrink, the material, the gate locations etc. The casting company wont do any of this for you. They may' suggest where to place the gates, but you will have the last call. You wont know if its all ok until you have one fully machined up, and tested. Then, you can carry on with that cast plan. If you come on voids, or it shrinks a little more in one spot, will you know what to tell the casting guys what to change? And will it make it better or worse?
You say you need more chamber area support/stiffness/strength, how are you going to decide what is enough, or too much that you will have a massive hot spot/mass of metal?
You need to understand Im NOT trying to put you off, just make you aware, that is all
I also would not like to be paying someone to machine 4340, and as complex as a head.
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fascinating, there are so many compounds and metal combinations, it would be really difficult to come up with just the perfect thing. I suppose it is time to do some more research. I really can't spend my whole lif on this, I need something that fits the bill and not re-engineer the entire head. In order to make this there will be a lot more than just redesigning the cast to compensate for thermal expansion? I don't really need to worry about that, even cast is better suited to the temps and pressures that the head will ultimately be subjected to.
GIVE UP??? I want what you're smokin I don't understand that concept. Try getting off of the "everyone says it's too hard", or the common "ugh, just too much work for me" prescription and perhaps you will not only succeed in you aspiration but also fare much better in life. I think that the best lessons are earned through hard work, but we have no choice but to stand on the shoulders of giants, however, to redesign an idea that already works is never an unwise choice or fruitless effort.