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I have an idea for an engine I want to try and bring to life for a small production car company I want to try and create. This came from my original thought for a car with a 12v53 Detroit and after not being able to find the information I wanted I got to thinking about maybe being able to do better on my own, and so I thought about basically combining two 5.9 Cummins into one engine using standard rotating assembly parts, less the crank for obvious reasons, and change it from an overhead valve design to an overhead cam, I think for simplicity I'd go with a direct acting, dual overhead cam setup, since it's a large displacement diesel, torque won't be an issue and from what I know OHC engines tend to make somewhat more horsepower as compared to OHV engines, just look at a comporably sized LS and Coyote engine. I think common rail would be better for ease of building as it simplifies the valvetrain as compared to EUI and MUI, plus it allows me to use off the shelf 5.9 engine-side fuel system parts as long as I size them right, so there's reduced costs as well. My problem comes in with forced induction, I want to do a reverse flow head design since it'd be easier to package with an air-to-air intercooler as I can build more free-flowing intake manifolds for each head as compared to the stock manifolds for the Duramax. I think for more simple exhaust plumbing I'd want to build basically a turbocharger setup in the footprint of an 8v71 blower but then there's the question of boost managment and how to actually do this. I think my idea would be to have a separate intake and exhaust side like a traditional turbo, however I have basically two blower sections, the exhaust side is gear driven to the intake side. Because it'd basically be a Roots style blower setup would I need to worry about non-linear boost levels and therefore need some kind of wastegate? Or am I overthinking that and it wouldn't be necessary? Am I overthinking this whole thing and it wouldn't sell because no one would buy a car because it's such a weird idea and therefor an expensive idea?
 

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I don't understand your thinking. Cummins is an in line 6. Cummins has dual overhead cam engines in the ISX line as the ISX15. That one is 15 liter which is used in HD trucks. They have V12 engines like the VTA1710 or VTA28 which is 28 liter. That one isn't OHC. That one is 6 feet long and weighs 4.5 tons. They have bigger ones too.
 

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If you have the millions in cash it would take to develop this and are going to spend it regardless send me a message. I'd be happy to help make your engine.

If you're like the 999/1000 "inventors" that think their idea is gold and haven't the money nor skill to invest in development then don't waste my time.
 

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My thought was a fully custom engine, from block to heads. The rods and pistons were going to be standard parts from a 5.9, the injectors, fuel rails, and injection pump, from a 6.7 Cummins. I heard back from a company I contacted and this would have been well above my price range, on the order of ten to fifteen million dollars and would've taken about three years of engineering work to bring to life. That alone killed my intent to do this, it's well beyond my means at this time. I thought this post had published earlier but I thought wrong apparently
 

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My thought was a fully custom engine, from block to heads. The rods and pistons were going to be standard parts from a 5.9, the injectors, fuel rails, and injection pump, from a 6.7 Cummins. I heard back from a company I contacted and this would have been well above my price range, on the order of ten to fifteen million dollars and would've taken about three years of engineering work to bring to life. That alone killed my intent to do this, it's well beyond my means at this time. I thought this post had published earlier but I thought wrong apparently
I feel like it could be done for far less if you utilized as many oe parts from a cummins as possible. I wouldn't go overhead cam and overcomplicate it. Have a custom machined wet block made to accept two cummins heads on two banks of six cylinders, two cams, etc. If the intake shelfs were machined off the heads one could be mounted backwards to create your reverse flow setup. A custom crank would need to be machined but thats doable. It would be expensive, but not MILLIONS. Limiting the custom parts to a block, crank, gear housing, and misc. covers would drastically reduce cost. Another thought would be to use two oe cranks meshed together with gears to transfer power to a flywheel. One bank would need to be reverse rotation but thats easy enough. Lots of ways to make this happen with a lot of money and a little thought.
 

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I don't think it matters how you slice it. You're not going to design, prototype, test, produce and support a custom engine for less than many millions of dollars in cash.

Emphasis on the cash part. Nobody would invest in an ICE engine today.

You have to write repair procedures for people to work on it. Emissions certification.

You dealt with many patternmakers and iron foundries these days? Any idea how hard it is to get ONE of something very custom cast? It's far more economical to machine from solid or fab from plate, but that doesn't learn you a thing about the production part.

Millions of $$$ is no exaggeration.

To make one custom engine that hopefully runs, no, it would not cost millions. To develop an engine that is manufacturable. Yes, it will cost millions.
 

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My thought was a fully custom engine, from block to heads. The rods and pistons were going to be standard parts from a 5.9, the injectors, fuel rails, and injection pump, from a 6.7 Cummins. I heard back from a company I contacted and this would have been well above my price range, on the order of ten to fifteen million dollars and would've taken about three years of engineering work to bring to life. That alone killed my intent to do this, it's well beyond my means at this time. I thought this post had published earlier but I thought wrong apparently
How much would you think it would cost you for full customization?
 

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To the OP:

I think it would help, if you'd specify your desired end-point. Are you wanting some specific engine weight/power/torque? Or, what?

Roy
 

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Anything is doable, if you have the resources and the time. The thing I see is very few existing parts will be usable. Pistons, con rods, valves, maybe a few other parts but not much else. Everything will have to be custom, and theres where most of your costs will go. Combining existing engines isn't a new thing. In 41, Chrysler combined 5 inline sixes to create a huge 30 cylinder multibank engine which was powerful enough for tank use during WW2;


Another problem with merging two 6BTs is, the thing is going to be really heavy and all of that weight will be resting over the front axle. V12 diesels already exist, and you could probably find one for not too much (compared to a fully custom design) You may want to try that route.

Good luck
Ed
 

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I think a lightweight 5.9/6.7 Cummins in a VR6 configuration would be neat. Single crossflow head feeding all cylinders. Packaging that would allow it to fit in smaller places than the inline engines.
 
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