Slant Six Forum :: OHC! A fun mental exercise.

Another, perhaps more practical discussion would be one on combustion chamber design. I have been told the slant combustion chamber is bad, but dont; know why. What can be done to change it? How hard would that be? Do you weld it up,and then grind to suit? What can we do to existing heads that is somewhat cutting edge, short of trying to redesign the entire thing with hemi shape, cross flow, and canted valves. Any thoughts on this?

I've sometimes been tempted to measure the bore spacing on a BMW M20 or other small inline six. Of course, every time I suggest that to the local BMW shop, they ask why I don't just transplant in a BMW motor.

Of course, every time I suggest that to the local BMW shop, they ask why I don't just transplant in a BMW motor.

Author:	sandy in BC [ Sun Dec 02, 2007 7:33 am ]
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The Jag head swap uses the stock cam for the dist drive and has a small chain drive from the cam sprocket to the head. I used 427 Ford SOHC parts....I like to use the aluminum block for easy machining but the iron block works fine as well. The stock Jag cams work fine. EFI is easier than setting up carbs on the passenger side. Most people can dop this swap in a weekend. Total cost $800 The biggest problem with this bolt on swap is a lot of people just dont believe...... HOAX HOAX........yeah its a hoax

Author:	66aCUDA [ Sun Dec 02, 2007 7:45 am ]
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Sandy You need a disclaimer on that. I bet I will see this pic on another forum.LOL Frank

Author:	slantasaurus [ Sun Dec 02, 2007 8:13 am ]
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Where has Doug been for this whole debate ???? I'm sure he's stayed awake at night thinking about this before. And Sandy.....cut that out !!! LOL !!!

Author:	Doctor Dodge [ Sun Dec 02, 2007 8:48 am ]
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I have been watching... (Truth is that I am spending every extra minute I have rebuilding engines for the 2008 racing season, currently have 3 going, not counting Twiggy) Making a OHC SL6 is a nice "dream" but there is so much engineering work and other custom parts that would be needed. I am keeping my "pipe dream" focused on a aftermarket "new technology" cylinder head for the SL6, once I have that going, maybe we can use that casting equuipment to put OHC provisions onto the top of it. DD

Author:	Aggressive Ted [ Sun Dec 02, 2007 8:30 pm ]
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Very cool! Now that is worthy.....get back to work! I want one.

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Author:	68barracuda [ Sun Dec 02, 2007 10:03 pm ]
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Quote: Another, perhaps more practical discussion would be one on combustion chamber design. I have been told the slant combustion chamber is bad, but dont; know why. What can be done to change it? How hard would that be? Do you weld it up,and then grind to suit? What can we do to existing heads that is somewhat cutting edge, short of trying to redesign the entire thing with hemi shape, cross flow, and canted valves. Any thoughts on this? I agree all the way

Author:	Sam Powell [ Mon Dec 03, 2007 5:01 am ]
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Doug, you can count me in as a very strong supporter and a very likely purchaser of your new head design. I would not get too hung up on the OHC part of it. I think the slant could function very well indeed with a good push rod head. Are you thinking cross flow, with exhaust on the pass side? Do you plan on using the stock intake? That would simplify things I suppose. I would not have to redo my EFI manifold. Sam

Author:	MindforRent [ Mon Dec 03, 2007 5:33 am ]
Post subject:	Well, that was certainly enjoyable.
Wow, I'm impressed with the shear amount one can learn simply from asking a single question. I don't know what else there is to be said. From what I've read, it seems that the feasibility of this project is low, and best left for mental work rather than metal work. The valve train is not the limiting factor of our engines and their ability to make power, that stems more from the induction and combustion limitations afforded by the head and bore/stroke ratio. So until a merciful/slightly loony millionaire agrees to set up tooling for a sparkly new head, we're going to have to make do with what we've got. I do like the way that Sam's thread is progressing and it should prove to be interesting. But hey, if it provokes a few of us to thinking, then it was still a positive outcome.

Author:	440_Magnum [ Mon Dec 03, 2007 10:42 am ]
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Quote: I've sometimes been tempted to measure the bore spacing on a BMW M20 or other small inline six. Of course, every time I suggest that to the local BMW shop, they ask why I don't just transplant in a BMW motor. Because you want the engine to actually RUN for more than a week at a time?

Author:	slantvaliant [ Mon Dec 03, 2007 11:53 am ]
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Quote: Of course, every time I suggest that to the local BMW shop, they ask why I don't just transplant in a BMW motor. If I were gong to put a BMW engine in a car, it'd be this one: (5.0L V12) It would make a good stand in while Sandy finishes welding those two Slant blocks into a V12 for me.

Author:	68barracuda [ Mon Dec 03, 2007 12:35 pm ]
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Welding 2 blocks up to form a v12 is not far fetched On discovery they showed a chap from england who converted 2 X 6 cylinder kawasaki 1300cc engines into a 2,6L V12...... now where is that rich uncle and a pile of welding rods and a full equiped machine shop 450 CID twin slant........YUM

Author:	sandy in BC [ Mon Dec 03, 2007 2:15 pm ]
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the connecting rod journals are wide enough.......

Author:	heckshemi [ Mon Dec 03, 2007 3:41 pm ]
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There's really no need for a ohc unless you turn high rpms or run 4 valves per cylinder. Compare the ford modular V8 to the new hemi or Ls1. I know which one(s) I would rather have. But I think there is something to be gained by going crossflow. I've thought about converting a ohc head to pushrod. I have looked at the bmw heads. There are basically two families of bmw sixes. The bmw "big" six bore spacing is very close to the slant six. It's a semi-hemi with nice sized valves and ports. I picked one up off of ebay cheap. My next slant six will have a crossflow head. But which one? Still working on that.

Author:	Sam Powell [ Mon Dec 03, 2007 7:06 pm ]
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How do you deal with the cooling passeges lining up with one another? Can you fill those holes and drill new ones that match the slant gasket? Sam

Author:	THOR [ Wed Dec 24, 2008 1:55 pm ]
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For anyone who couldnt read the text on the picture of the OHC slant for sale, go to the picture, hover over the picture, then press CTRL (bottom left 'o keyboard) and then use the scroll wheel on the mouse to zoom in on the picture. Voila! ~THOR~

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