Technical Discussion: Ardun Style Heads For a Cadillac Flathead

I was reading George Millers thread about the two piece OHV head he made. I started thinking (dreaming) about how to make a two-piece, Ardun style head for a Flatcad. It would take a LOT of design and machine work, but I can't think of a reason it can't be done.

What do you think? Any ideas on how to do it?

 

if you convert it to overhead valves is it still a flathead?

 

Will the bottom end handle more rpm/hp ?

 

I don't think the bottem end will be an issue. Fiinding the right valve train, and design fitament will be the real issue, I think.

 

Worry about your cam drive first.


If I was going to copy a head design,
a Hemi would be good with a blower/turbo.

Normally aspirated, there is better stuff available.

 

Anything CAN be done-it's merely a matter of focusing the proper level af skill/talent and $ on the project. That said, that proper level of $ might be more than one can handle. It would be easier/cheaper to design and build a set of wedge heads with all the valves in a row as opposed to a hemi with its complex rocker arms and splayed valves.

 

Four overhead cammer?
If you´re gonna do it - then do it!

 

38Flattie,

Well, I'm going to be in Colorado soon, maybe I can stop by Norm's and ask the question. I know he did make a couple of "Miller" type overhead conversions for the V8 Ford awhile back. The set I saw with intake were around $4k, my guess is that it would a "Little" more than that.

What is the bore spacing on the motor, and what is the deck width and length?

 

2011 Bonneville will here before you know it. Quit worrying (dreaming) about OHCs and shit like that and get the Caddy ready to run.

 

Don't worry, I'm just looking at this in my 'spare' time!It isn't for this years build, which is moving right along!

 

Sorry, but I would go with a hopped up 500 Cad and be done with it.

That said, find out what the bore spacing is and compare it to the MOPAR early hemi engines and see if you can't cut and weld up a pair pair of the MOPAR heads to come up with one viable Cad head, then make two of them. Doubtful tho, but I don't know...

And I do like the MOPAR Poli-heads so check PLEASE them out...

pdq67

 

Surely if Duntov could make Hemi heads for a Ford V8 and the V8-60 and MT could make them for Pontiac and 429 type Fords as well as Aries and others making them for BBCs they could be made for a flathead Cad. Not much of a market out there for such a thing I think.

 

I think you're right Rich, in the fact that they ARE doable.

And I wasn't worried about the market demand, I want them for myself. I don't think there is really a demand for any of the Flatcad stuff.

 

Belive it or not, there was rumor about a cat here in the springs getting a set made. I met him. He would not confirm nor deny the idea. He did say that if a guy were to get them made they would be pricey...

 

I would like to some pics of those!

In reference to the caddy heads, it would be cool to see. However personally unless i was building a uber custom car with all fabed parts it wouldn't be worth the $ and besides the vintage stuff will always be cooler. just my .02

 

I'll PM them to you when I get home. I'll PM my number also. When you get to Colordo, I'll buy you a beer. If you want someone to ride to Norms with you, holler!

The only 'vintage' stuff is Cyclone or Edmunds flatheads, and a Burrell 2x2 intake.

Besides, this is a racing motor: http://www.jalopyjournal.com/forum/showthread.php?t=496866

 

Just wait 'til someone unearths all those French Cad Flatheads. There'll be your short blocks and bottom ends!

 

Thats funny!!!

Hmmm, no brilliant ideas out there?

 

The French engines wont be legal for the class.

 

This seems to come up whenever there’s talk about overhead conversions. Do you know of an easier way to quickly inform the listener/reader that you’re talking about a pre-1949 Cadillac V8?

I thought along those lines myself. Overhead valve Caddy = ‘49 331. Hemi 331 = 1951 Chrysler.

But I understand the original poster’s desire to stick with his current engine. For similar reasons, I occasionally think about digging up a 1961 Falcon six to hop up for my car, when it would be way more logical to find a 200ci engine from a later car.

To answer the original question, I’m sure it can be done, it just takes cubic dollars; fabulous engineering and machining skills; or incredible perseverance. Go for it.

-Dave

 

If Buddy wanted to run in XX class with a LaSalle size flathead Cad he would need some sort of OHV conversion. As is is he is in XX class by being over 326 cid but under 375. So which has the greatest potential. A 324 inch Hemi "Flathead Cad" or a 374 cid true flathead Cad? Who knows? That's what the salt is for.

 

On paper, the Hemi should be stronger, even though it is smaller.
But that assumes you can rev it higher, to take advantage of the improved airflow.

 

Well, in 2011, we'll see what the FlatCad does.

...and I think in 2012, we'll see what a hemi headed, OHV conversion will do. It would be nice to make it so that a Hemi blower intake would work

 

Pete Ardema Spelling may be off.

 

Thanks Rich! I'll contact Aardema this morning!

 

Much to pre-plan. Lots of coffee, beer, with the brains cells churning. But, of course, it CAN be done. The fabrication is the lesser part of the equation. The initial design is the major potion. Although, both parts are critical. If you accomplish this feat then I bow down to you. ANYTHING can be done, just take any problem and beat it to death with hundred dollar bills. (smiling) Please keep us updated on whatever takes place with this idea. At least, it seems as though here's a true hot rodder who doesn't BUY all his bits amd pieces from a catalog.

 

Thanks! Have you seen the current build? Between the original build for the Lasalle, and the Current build for the FlatCad, almost everything for the engine has been designed and built by HAMBers!

Where at in south western Nebraska? I'm a Nebraska boy at heart, having grown up in Bridgeport- my mom still lives there. Go Big Red!

 

never seen the inside of a caddy flatty. but, it would be a matter of making push rod guides where the valves went, that continue up into the head. thread the top of the guides into the top of the head lower half, with a machined stop/seal at the end where it will stop at the head. you will need to make sure that you feed an oil line into those somehow. so you could maybe have an oil feed go into the head, then drill one continues hole from one end to the other, then plug the hole in the end. then drill feed holes in the rod guides where that oil feed is. that would make for easy cleanout too. also drill a few holes from the top to feed the rockers. depending on what rockers you use would determine how they are fed. but maybe 235 rockers would be easy to adapt, because they have an actual line feeding the rocker assembly. then you will need to make a feed from the push rod feed i talked about earlier. possibly a top bottom valve design. intake being on top and exhaust on bottom. to keep the flow "thru" the head.

 

38,
I have also thought about the addition of an Ardun-Hemi style head on an AMC Inline. I have many drawings and doodles of port layouts and such. Mind you I said doodles, I'm nothing more than a AMC/Jeep guy with a little knowlege and an Idea.

For your application, Lets atart with the lifter area. As you've posted the Cad has a relitivly empty lifter valley. Could this emptyness be used to create a modified lifter block to take advantage of possible lifter/pushrod angles? If your going all out I figure why not. Also being a previos flat head there could be considerable room for a pushrod in the old I/E ports.

Would you need more-bigger head bolts with all the 'extra' movement and forces going into the heads?

The heads themselves would not be that disimilar than any other Ardun/Hemi head. It would all be in the packaging. I would assume that a shaft style rocker arangment would be used just for ease of attachment, oiling and availability. For that matter alot of the geometry could be borrowed aswell.

Port design I have always tinkered with and thought about. I always liked the Idea of a straight intake port, In my mind the flow would be better being 'pulled' stright down into the valve rather than bending around it. Maybe you could use a swirl or twist port to keep the AF mixture in suspession? Maybe that would have no affect at all just a thought. And for the exhaust a smooth graceful arc after the valve would creat a good trasition into the header. I aslo seem to remember reding somwhere that if you do not cool the upper half of the exahust port the temp differance created will aid the airflow being pushed out of the cylinder.

I'll be in Denver/Colorado Springs over the Easter holiday, I'd love to see the car and engine if they're in town. Good luck on the Salt.

Jeff

 

dont know if this makes any sense but this is what i was thinking in my head. granted this is without the cooling system.... i mean i did it on ms paint theres only so much i can do hahaha.