You might be able to cast something as large as a inline six head, but it's pretty iffy. You might make something that large, but few would have the discipline to work out the bugs. It really is like a recipe, but if you mess up you might have to chissel a chunk of solidified metal from your crucible. Once you built good patterns and mastered the technique you could pour good quality castings fairly consistently. Many of the best "how to" books were published many decades ago. Most of the foundry workers never understood the science behind the skill.

Even if you only cast a chunk of alloy billet you would save a bunch over buying the metal wholesale. Many alloy dealers won't deal in small quantities of metal. Try to purchase less than a rail car of coke

Get those diesel pistons if you can. In one of Chastain's books he displays a 165 pound pile of ingots that he cast from junk pistons. "Pistonium" is the best metal. The forged pistons are top quality alloy that would cost much if you purchased the metal wholesale. Some alloy has high silicon content that makes it hard to machine, forged doesn't. Iron is common if you have a hankering for rusty metal, iron machines well too.

Alloy is caustic and will combine with impurities, you can burn most inpurities from iron. If you can get coke cast iron might be the best way to go. If you're the type who could disappear for months at a time to the furnace in the barn a foundry might be for you. You can master 1940s production techniques with a hobby furnace, something as sophisticated as the Ardun heads is within reach.

These days CNC skills are probably more critical to low volume head casting project than foundry knowledge, you can practically whittle the entire project from a chunk of raw metal. If you could cast a rough casting with water jackets the rest could be CNC milled, relatively low cost, cheaper than the $13,000 that the Ardun heads go for

If a new head were to be cast, how would it be different from the stock one? And couldn't the stock one be modified to include these new features. It seems the stock head has a "squish" area and the spark plug is centered in the cylinder. What other features are needed? You know you do have sort of a fixed diameter to work with and only so many valve size combinations will fit. So what's the big deal?
Sorry, just showing my ignorance.

Hey Doc, how about a dissertation on head design?

bwhitejr

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'72 Duster (Performance 360)
'83 Ramcharger (Performance 318)
'80 TrailDuster (360)
'80 D-150 Truck (See Below)
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Ported, Polished and Gasket Matched
P4286813 Springs,0.040 Overbore,
0.090 Shaved Head

Well, I am no doc but I have spent plenty of time on a flow bench. Most heads today have taller runners and longer valves. There are so many simple things that makes a head flow better. Some things you would swear that it would work but it does not, other things work and make no godly since. I have a set of heads on one of my engines that flows 540 cfm @ 28". It has 7" long titanium valves and a 4.625" bore so 2.455 intake valves and 1.90 exhaust valves can be used. That is just pure size allowing more air to pass through. We are going to try to get around 235 or 240cfm out of my slant six heads. Honestly, I doubt if it can be done. I guess it really does not matter because a 70mm turbo is going to force it through. I am making my headers for the t-4 turbo keeping them to only 1 1/2 inch to keep the velocity up.

Pretty intresting cylinder head

http://www.customdesignperformance.com/ ... _head.html

It is for Chevy 292, but couldn´t it be done to slant six too.

That head looks good. There was a guy here in Louisville Ky. back in the 70's that used a cleveland head and put it together like you did. He set national records one after another. It was called TROUBLE MAKER. The guy's name was Joe Williamson.

That's very cool. I've always wondered if that couldn't be done to make a /6 head, ever since I toured the Dart head facility in Troy, MI. They were repairing damaged alum. racing heads. What they could reconstruct from pieces was impressive. I guess the question is, is there a Mopar (or other?) V8 head that shares the bore spacing of the slant 6 that you could make heads from?

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DynoDave
1970 Plymouth Duster
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1977 Chrysler Cordoba
WPC # 12304

The only two heads that I know of that have the same bore spacing of the Slant Six is the classic Jaguar OHC six, or the Toyota T series four. The head bolt spacing of the Jaguar is not quite square as the Slant Six(has to be wider because of the twin cams), the cam drive is complicated to adapt. The '50s pure hemi versions made 260 HP stock high compression, later models with quench pockets and low compression for emissions don't perform as well. The bore of the Jag six was up to 2.66" or so, with 4.19" stroke on a 4" spacing with siamezed block. I believe the basic bore/stroke dimensions of the SL6 came from the Jaguar six.

I like the T Series because its pushrods are in the right location and its a hemi with centally located spark plug. The ports of a cut-and-weld T series OEM head would be too small as a stroked and bored 3TC is only about 2 liters. The exhaust manifold is on the same side as a Slant Six, there would be not much space for an intake, but the SL6 could be mounted more upright.

There are aftermarket CNC milled big port T series heads, this motor is well supported around the world. I am not thinking of a daily driver, or a deal for the regular guy, but a few Hemi heads to dream about. The hemi might not make more power, but it would look great

Actually, just a slight correction re the jaguar heads.
The later versions of the 4.2 did not make power due to tightening emissions, and it's obvious effect on a large, open chamber head like the Jaguar has. The engine was detuned and strangled with cat convertors etc. The camshafts are also very mild. Compression was dropped with the pistons, not teh chambers.
The fuel injected heads had the largest valves of all production Jaguar heads and are also by far the most plentiful.
I used to own a euro spec (no emissions equipment) series 3 Jaguar, and although the car was extremely heavy, that wonderful six did an excellent job, power was definitely there, so teh head must be half decent.

Regards, Andrew.

The DOHC Jaguar heads could be adapted, but are overkill. I think the hemispherical crossflow Jaguar chambers are good, but the pushrod T series has that too. Pushrods are cheaper and lighter and would make as much power in the reasonable RPM range. The OEM double rocker arm valve train for the T series is adequate, aftermarket parts are readily available.

The Jaguar cast iron exhaust manifolds might be okay to use, these are common in salvage yards. There two sets of threes of equal spaced ports. Aftermarket Jag six headers are available that might made be to fit.

The side draft T series intake manifolds often come in 2 sets of two. If the intake side pattern was based upon the 3TC I think it would be possible to use three off the shelf T series intake manifolds.

The T series fans say that the pushrod hemi T heads can make as much power as the DOHC versions (export only) when fitted with big valves and modified ports. Some say that the pushrod T head has raised ports when compared to the DOHC ports.

I think there might be some common parts to use to make the costs of a Hemi six more reasonable than it might at first seem, although I doubt few would want to use OEM style cast iron Jaguar exhaust manifolds, we might be able to do that. I think some T series pushrod hemis go to 8,500 +RPM.

The T-series is not a thinwall casting, it's very robust. The little motors can actually make more power than a modified Slant Six, especialy when boasted with supercharging. The long inline 225 has similar problems of the Jaguar six, which has torsional block stress as the power increases. The hemi head is probably overkill on the 225 as the block couldn't handle much more power than racers get with the current head.

The Dodge Viper now has variable valve timing via two concentric camshafts in the block in the traditional location. I wish Mopar would build a new inline six, or maybe use the Viper head for an inline five. I've not seen any diagrams of the new Viper camshaft.

And still they persist.

"the basic bore/stroke dimensions of the SL6 came from the Jaguar six"?

And the source of this fact is?

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The source of the admiration of the Jaguar six by Mopar engineers in 1957 is anecdotal, but it is widely understood. When I was a kid a very fast toy car was always a Jaguar Lemans racer. The four bearing bottom end of the SL6 is closely related to a Mopar L-head, such as a 236, but I've never heard a Mopar engineer say that much, it's just recognizeably true. The Jaguar is smooth and torquey, but unreliable and expensive. The SL6 could have achieved most of the finer points of the Jaguar with a little improvement at the cylinder head.

I worked in General Motors design center twenty years ago. A Ferrari was placed at the receptionists desk. The engineers freely admited to admiring certain designs (such as the then new Chrysler minivan). If you were to take a head gasket from a 3.8 Jaguar it would overlay a 225 block deck identically with the exception of the Jag bolt pattern is more widely spaced. The SL6 is an economy engine, but I believe it is fair to state that the Mopar classic OHC six was inspired by the motor of that day which achieved the highest specific power output of any production motor.

http://g-speed.com/pbh/bore-vs-stroke.html

"Compare this to the classic Jaguar 3.8 liter twin cam as fitted in the XK series Jaquars. Don't think that this wasn't a racing engine -- it was the real thing in its day, with a long string of victories that included Le Mans. The Jaguar motor has only six cylinders and slightly larger displacement than the modern Ford Formula One V8. The bore is 3.45 inch (87 mm) and the stroke is 4.17 inch (about 106 mm) or just about the opposite of the F1 V8. The Jag has an incredibly torquey stump puller of a motor, but one with a redline in the 5500 rpm range. Because the rpm is limited by the long stroke and heavy pistons adequate breathing is provided by a single inlet valve in each cylinder. Under square? Radically."

Tim

What is a "Mopar classic OHC six ?"

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David Kight
'62 Valiant Signet, White
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Growing older is unavoidable but growing up is strictly optional.

it's just recognizeably true

Mmmmmm... Science!!!

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Naw, it ain't. It's numerously repeated, which is not the same thing. Having spoken of the matter to one of the primary engineers who was actually designing the slant-6, I am pretty confident saying all variants of the "based on Jaguar" or "much admiration for Jaguar" tale are fanciful ex post facto rumours, nothing more.
C'mon, you can think a lot more clearly than that; I've seen you do it. By this tortured logic, a 2006 Hyundai Sonata was inspired by the 1961 Dodge Lancer upon which it was based. A stupid assertion? H'mm...four doors, four doors. Four wheels with tires, four wheels with tires. Four headlamps, four headlamps. Two taillamps, two taillamps. Front and back seats, front and back seats. Windows that go up and down, windows that go up and down. Six cylinder engine, six cylinder engine. Wheelbase in the neighbourhood of 100 to 110 inches, wheelbase in the neighbourhood of 100 to 110 inches. Do you see the giant flaw in your assertion yet?

I grant you that it's fun to let our imaginations take us on rides from time to time, but it's also important to keep in mind the difference between facts and fancy.

Also, there is no "classic Mopar OHC six", nor was there a 236 CID Mopar flathead-6.

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Too many people who were born on third base actually believe they've hit a triple.

C'mon now. everyone knows the Slant was based off the V-12 Panzer tank motor.

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