December Engine Project

[SchmidtMotorWorks]

I'm making plans for a December project.
here's what I have to work with:
* 20 vacation days
* 2 credit cards with high limits
* Bills caught-up
* All current projects will be finished by then so the shop and machines will be empty.

So here is what I am thinking, since I rarely make any money on the stuff I make for the existing racing market, maybe I should just make something for fun that I have wanted to do forever.

I am thinking about making a set of patterns to make head and block castings for a 60degree V12 with 5.0 bore spacing. I am thinking of making it a 15 degree valve angle hemi that the rockers share one shaft. I have done a layout and the rocker geometry works out nice when the cam is raised very high as it needs to be for a 60 degree V. Maybe I should just copy an existing valve train but kind of want ot to be a little unique and not just a clone.

Then starting January start casting, buying and piecing the other parts together.

The billet carb idea and the EFI idea just don't seem to have the attraction needed to make them into projects.

So unless someone has a better idea of something else to make, a V12 will be it.

Open to any other project suggestions.

[bobqzzi]

Sounds exciting. Hoe about making a DOHC 4v V12? You could even use an existing straight 6 head.

GM makes a 4v 4.2 I6 that makes 291HP- so even if you left it stock you'd make 600hp.

You obviously have tremendous fabrication/casting/designing skills and I'd like to see you build something modern.

[SchmidtMotorWorks]

You could even use an existing straight 6 head.

GM makes a 4v 4.2 I6 that makes 291HP- so even if you left it stock you'd make 600hp.

Thanks for the suggestion, I considered that but there already are small 4v V12s out there, you can find a BMW V12 in the wrecking yards here for $1500 sometimes.

Using the 6 cylinder head is a little tricky, I have one here. One head would have to be turned around and the cam drive would be a big problem. Plus it has small bore spacing and kind of low ports.

I general I am afraid of DOHC because of the cost of 4 cams and the cam drives. Plus it makes an already too tall engine even taller.

I will make the head bolt pattern so that it will be useful for a DOHC so that it will be possible in the future.

[bobqzzi]

8.4 liters is small!!!!!!!

[SchmidtMotorWorks]

8.4 liters is small!!!!!!!

Yes, compared to: 907 cubes (14.86 liters)

4.625 bore
4.500 stroke
12 cyl

[bobqzzi]

8.4 liters is small!!!!!!!

Yes, compared to: 907 cubes (14.86 liters)

4.625 bore
4.500 stroke
12 cyl

And you're worried about the engine being too physically big!!

[katman]

When you finish making the thing just ship it to KC and I'll mount it in my 79 Camaro and test it for you!

[SchmidtMotorWorks]

And you're worried about the engine being too physically big!!

Yes, I want big block dimensions and in a 60 degree V the engine gets rather tall. So I chose a pushrod design partly becuase it has better power density than a DOHC engine.

I have a design for a compact SOHC design but again the cost of developing the cams and rockers will be very high since they act directly on the rocker arms.

[WeRMany]

I just shake my head in awe at your idea of a project.

I've always wanted to see a modern retooling of the Merlin engine. Get the piston speed up there and the head really working. Do it with stroke to spare the valvetrain.

4V is an uneeded expense, and "Hemi" a quaint bit of history.

I think I'm suggesting a really big, long, Kaase engine.

[bobqzzi]

And you're worried about the engine being too physically big!!

Yes, I want big block dimensions and in a 60 degree V the engine gets rather tall. So I chose a pushrod design partly becuase it has better power density than a DOHC engine.

I have a design for a compact SOHC design but again the cost of developing the cams and rockers will be very high since they act directly on the rocker arms.

I have to disagree about the power density of pushrod designs being greater. Pound for pound a DOHC design will make more power. I know you've expressed your concern for the physical dimensions of the dohc being too big, but it seems most manufacturers manage to get them into cars just fine. A big block with 2 extra cylinders sticking off the front is going to be harder to fit in a car than a shorter, but perhaps taller dohc design. A DOHC 90 degree V8 does get wide, but the 60 degrees of a V12 wouldn't be as wide. The height issue could be ameliorated by an efi manifold that didn't rise much above the top of the heads- afterall, you have quite a bit of room where the cam went.

Gigantic displacement (while extremely cool) seems a poor way to make up for an inferior design. I just can't see a reason to design a whole new engine around this arcitecture.

In any case, I'm sure whatever you build will be quite interesting.

[Ron E]

...But doing a DOHC 4V motor would be a recreation of what every manufacturer is doing. What would really be the point?


If nothing else, validate the concerns of all those around you who, in the past, questioned your stability.
Give'em, something to talk about!

[SchmidtMotorWorks]

I have to disagree about the power density of pushrod designs being greater. Pound for pound a DOHC design will make more power.

I'm not sure that's right, The Ilmor Mercedes 5001 3.4 liter pushrod V8 made 1024 hp at 9800rpm. It had similar overall size but larger displacement than the DOHC stuff 2.6 liter at Indy in 94. The Ilmor engines had 12.5 boost and the DOHC stuff had 10. The Ilmore engines dominated that year.

If it is just hp per cubic inch, of course, the DOHC has an advantage.

In any case, the development cost of the cams and drive systems are more than I can afford in time or $. The push-rod is a slam dunk by comparison.

Engineering a cam with rocker arms is a really big deal becuase the contact point changes through the lift range and ramp angle. I would estimate the cost of engineering a cam like that to be more than the entire pushrod engine will cost.

[SchmidtMotorWorks]

..But doing a DOHC 4V motor would be a recreation of what every manufacturer is doing. What would really be the point?


If nothing else, validate the concerns of all those around you who, in the past, questioned your stability.
Give'em, something to talk about!

Exactly!

[Joe Mendelis]

Schmidt, It's fun to think about a 907 inch engine (man that's nice and big!), but if you came out with a bad dude cylinder head design you could make a lot of money off of it! Not many guys will spend the money to build a 907 inch V12 exept for special projects. You seem very smart and have the cad capabilities. I would think LS1 or small block ford would be a good way to go. Nobody has a really good LS6 casting yet. I know it's not very original, but there is a big market for them. Small Ford?
How bout EBAY?
Do a CAD design for a $20,000,000 POS?

[katman]

Contact Jay Leno, He might fund it. He likes big, different things.