For our purposes we've been using it for working prototypes and for tooling models for castings. The paper laminations are impregnated in a machine with a resin (not sure what kind), put under pressure, then placed in an ultrasound oven for cure. The result is pretty darn impressive. You would never guess that it was paper and I've been told by the techs that it might even make a pretty good intake manifold since the resin is stable up to over 350F. There are some joining techniques for aluminum that could work for a cylinder head. One that we've used is called dip brazing or furnace brazing. The parts are cleaned, then coated with a very thin, fluxed brazing material, then joined under pressure. The assembled layers are then placed in a furnace and heated to a specified (pretty high- 1200F?) temp, then cooled. When you pull them out, they look like one piece. When you cut them apart you usually can't tell where the material starts and the braze begins. Any secondary machining or heat treatment is done afterwards and the parts look pretty good. One other technique that looks interesting, but I have not personally seen in use yet, is the weld deposition method. Basically, it's a robotic MIG that deposits a metal weld like an inkjet printer, building up the part as it goes back and forth. It is driven by CAD software like Solidworks and reproduces the model in steel, aluminum, or bronze. I kind of like this idea.....go out and "print" a new manifold or cylinder head.
That DHOC head looks like a killer setup, but something tells me that the bore spacing will not be the same as the stovebolt block. I've done my back, so cannot move my stuff to check ..... bugger it all! The Aussie x-flow doesnt come anywhere near fitting the stovebolt block, its way too short and the bore spacing is too close, as stated above.
Hmm, weld yourself a new head. Now that would be an accomplishment if you could manage it by hand. I imagine the machine to do it robotically is buckets O cash. Furnace braze should be tough as hell.
Back in the 60's a bloke I knew in Sydney wanted a 12 port head for his drag racing Holden grey motor. (GM Australia product, inline 6, 139ci) He scoured the wrecking yards looking at cylinder heads, and finally found (I think) a Vauxhall (English) cylinder head that had the right 12 port configuration, but was a good half a cylinder too long for the Holden block. He sliced the head up into one cylinder sections, cut a slice off each one, and welded the bits back together so the combustion chambers sat directly over the bores. The mis-matched bolt holes were fixed by welding up the wrong ones and re-drilling them, and the mis-matched water jacket problem was sorted by building an external copper pipe system to deliver and remove water to the head directly from the radiator. The biggest problem he struck was the exhaust and inlet ports on the head were wrong way round to the cam lobes. (intake valve on exhaust cam lobe etc), so he got a 'reverse grind' camshaft built to his specs. That car ran like the proverbial 'raped ape' at the drags. The inlet manifold was just a set of six tubes, each with a single barrel 1 1/4" SU carb mounted on it, and the exhaust was six straight dump pipes leading out through the front wheel well. Maybe you shpould spend a bit of time at the wreckers or cylinder head shop with a tape measure and a digital camera. Look at every inline 6 out there, US, English, European, Japanese. Find something that's fairly close and preferably too long, and cut and shut it to suit. 'Chopped and channelled cylinder head anyone?' Cheers, Glen.
I've heard that the Humber Snipe may be a good head to look at. Its a "Hemi" design. I've not seen one though, but it may be an interesting project. Glenn - your story reminds me of what my late friend from Qld would do. Max Knight built a lot of things just for the sake of it, or to prove that it could be done. He supercharged the original 216 that was in his '39 chev roadster ... why ... because he had it, and because some-one said it couldn't be done!! I have the blower set-up now, and will run it on my coupe
The Pontiac Sprint etc. SOHC engine is a derivative of the Chevy 194/230/250/292, and has the same 4.40" bore cnter distance as the SBC. I'm not sure the 235/261 engine series is the same, but I doubt if it's as small as 103mm. The biggest BMW I can find is 100mm - much too close. The Oz etc. Ford 200/250 stuff is too close at 4.08". Ford 240/300 is probably too big at 4.48"., The AMC 232/258 head may work at 4.38". To figure the bore spacing error: Let's call the error the difference in bore pitch (AKA bore spacing, bore center distance) between new and old. For example: Buick BB to Chrysler B (common manifold swap in the day) is 4.75" to 4.80", or .050" misalignment between each pair of cylinders. Assuming that the water, bolts, oil etc. can be cured, the offset (error) of each successive cylinder is smallest if the new head is centered on the old block, with #3 & 4 sharing 1 error. If (example only) your engine is 4.30" and you use a head at 4.40", the error is .100". The 3 & 4 would each be offset in opposite directions away from the center by .050", #2 & 5 would each be offset by a full error plus the adjacent error or .150". #1 & 6 would each be offset by a full error plus the adjacent errors or .250".
FTF, yes, we know, and we can't get one of those either (lucky fellah that you are), has anyone pulled impressions of the passages in that head (the two part expanding stuff is what I'm talking about).
The Stovebolt heads don't have equi-distant bore spacings between the cylinders, like most other engines have. So, finding any head that is going to be a bolt on, is remote at best. On Inliners, we've been able to conclude, using 21st century CMM measuring technology, that the only practical alternative will be to graft several heads together, similar to what Leo has done in his book for the 292's! We've also been able to create 3D modeling of an entire 235 head with valve centerlines and intake and exhaust ports and head bolt locations relative to the cylinder bores and spacing for the Stovebolt , and could produce tooling to create new head patterns with better port layouts for casting if so desired as well as improved head porting technology, or a new 235 12-port version can evolve easily from that research also! Of course....$$$$ being the main limitation at this point!
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