Technical Discussion: Ardun Style Heads For a Cadillac Flathead

actually the more i look at it, the easier i think it would be to make them one piece with a rocker cover. just drill the oil passages from the outside, then plug the ends. press in the guides with the oil holes lining up.

 

I was thinking along similar lines- use the current lifter block area, to house a new roller lifter set up. The push rods could use the current port/valve passage way.

I believe the intake mixture could be introduced to the valve at somewhere around a 45 degree angle. I don't think 'straight 'is possible, bit it will be a blown application. I'd like to make the heads so that a stock hemi, or other stock intake, would fit.There will already be bigger, and more head bolts than stock, on the FlatCad.

The car is in MO at the moment. If we are behind schedule, it will still be there in April. If we are on Schedule, it should be in Ohio.

The drawing helps a lot!

I think you're right on the oiling, and it will be pretty easy to accomplish. Dry sump oil pump, so volume and pressure will be no problem.

I think the proper rocker assembly will be tricky, but doable.

I'm thinking two piece heads, for ease of production. I don't think the actual production will be as tricky, as the necessary CAD work will be tedious!

 

suscribed! this is the stuff i want to do in the future, crazy engineering!

 

Not sure why you need the pushrod guides. Most engines I have seen do not use them. The lifter and rocker arm hold the pushrod in place. On the three engines that it came up on, that I built. I ran an oil line from the gage port to one of the combined rocker shaft rocker box hold down stud which I made to extend high enough to allow a 37 degree end and drilled it to flow oil into the rocker shaft. Worked great every time

 

Rich, That sounds workable, and easier to boot!

What rocker assembly did you use?

 

?? :d

 

nice pic.

I was told the same thing when I said I wanted to attempt a 450 hp Cadillac flathead. Seems there is no info, no parts- simply impossible I was told. Now, in a few months, we'll put it on the dyno and find out how successful we were.

It's not important that you believe. I did not post to get approval, nor validation.

I posted for info.

One thing I am mulling over is the chamber design. The Hemi design would be easier, but I'm wondering if there might be more power in a 4 valve pent-roof design.

 

For the GMC we made our own rockers with rollers and pushrod seats and such bought from Isky. For the Plymouth with the Y block head I used Y block rockers. For the Dodge with the Morton & Brett head a friend found some rockers that were close and I made the stands and shafts spacers and what not and sent the whole mess to Rocker Arm Specialty's who made the finished roller rockers. I looked at putting a Hemi head on my Plymouth. A De Soto head would have fit great, but. There was no way to get push rods to the exhaust rockers. Depends on how close your cam is to the deck surface and stuff like that. That is why Duntov had to use the cross pushrods on the V8 60 hemi heads. It's not easy.

 

Good info Rich!

I know it won't be easy. I'm very curious to compare a 324 CID OHV conversion to the Flatcad. It may be, that the gains, if any, will be negligible, considering the CI difference.

 

lol, it was just a joke....

 

And why not 2 intakes and 1 exhaust? Thus leaving more room to the spark plug.

 

The Plymouth was 213 cid and used the same cam and pistons, rods and pretty much everything as a flathead and with the Y block head. In the same car, seen on left, and at El Mirage it was 23 mph faster with the OHV head, which was much less than optimum.

 

23 mp- pretty significant gain!

I have a couple of questions :

Did both engines have 213 cid-I see you used the same cam and pistons. In our class, as you are aware, we give up 50 cid to go to a specialty head.

You state " which was much less than optimum'. Can you tell us what you mean by that?

In you experience, and opinion, is this a worthwhile venture?

Thanks for the info Rich!

 

Yes both engines were 213 inches and 9.5 to 1 CR. The same rotating and reciprocating assembles were used in both engines. Same cam. Twin plugs on the flathead but it ran the same on one. A 57 Ford Y block head is far from the hot setup when building a race motor. And the bore spacing was close but not right. So every cylinder had it's own combustion chamber. One with the exhaust valve mostly over the deck. One with the intake. Two with both half and half. 3.750 bore was much smaller than width of combustion chamber in the head. But it ran and was interesting and fun. A Hemi or any OHV Cad conversion would be the same. Would it be better than scarring up a V12 Cad OHV engine to run in the same class? Or maybe an International Harvester or other truck engine of 370 cid? Depends on you and what turns your key. For me it was a Plymouth with a Y block head. Worthwhile to me.

 

because the area where the pushrods go would be part of the combustion chamber then. i guess you could make some sort of custom gasket if the area between the valves and cylinder is flush with the deck. so unless you welded it up there would be no compression! also the lifters dont have divots for the rods!

 

I think you have to explore the option of going overhead cam. I personally think that the set of issues it raises also solves bigger issues in the process. With the OHC design, the biggest issue is working out the cam drive, which could be figured out with some type of big timing chain or better yet, belt drive. By using the OHC design, you've made pushrod and rocker arm geometry a moot point. You'll need custom cams obviously, but with Ford's design you'd only need to drive one of the cams, you could also explore the DOHC design and a small secondary chain could drive the second cam. That configuration not only allows the "hemispherical" or "pentasherical" combustion chamber, but also will dramatically increase your rpm range.

Who know, maybe with some extreme modification, a DOHC Ford Modular head could be outfitted on your flat cad. That would be EXTREME

 

Not having looked at Cad flatheads much, most flatheads are flush with the deck surface between the valves and bore. That's why people relieve them. So that they wont be. Also when I converted the Plymouth from flathead to OHV I used lifters from an OHV engine (International Harvester Red Head) that were cupped. When I converted the Dodge Bros. I simply removed the adjusters from the Dodge lifters and installed cupped inserts that I made. All much simpler and better than your guides. Look at the motion of a rocker arm. It swings in an arc. The pushrod must be free to follow that arc. Yes I made my own gopper gaskets

 

I don't believe a DOHC head is legal in XXO/BGAlt

 

The area between the valves are flat, except for a small relief on the intake. I think filling that area, and milling it, is the best option. Here is a pic that shows the area pretty well.

And you are correct as usual Rich-No overhad cams allowed!

I have a tentative plan here, on how I'm going to do this. Having very little experience at this, correct me where I'm wrong.

I already have the current head design on CAD, so I'm going to make a 'blank' head, with only the head bolt holes, and holes for the push rods and valves. I'll scribe a circle to represent the cylinder bores. Then I can try and get the valve train to work, and I'll know what areas I need to leave material in when machining, for the valve train.

Once I get that figured out, I can work on the chambers, and valve seating.

Sound like a plan?

 

Yes. A little welding and decking and your home free. Good time to fix that crack. The challenge is finding someplace for the pushrods to go. You may find that a very tall lifter helps with your angles. You will have lots of fun noodling over this one.

 

gotcha, i guess now that i think about it i feel kinda silly. i guess you would have to make the gasket continue past the area and just make a hole for the pushrod. because if not wouldnt that leave the gasket weak if it was to thin there?

 

Don't feel too bad- you're drawing is very helpful to me, in imagining how to set this up!

I think Rich is right, in the fact that getting the pushrods in a place that will work in relationship to the rockers might be tough. Right now, it seems to me the intake rocker will run 90 degrees from the top edge of the head.
The exhaust rockers will have to run at an angle, or angles. The center to cylinders will probably prove to be the most challenging.

Rich, I sure as hell wish you were closer, so that I could pick your brain about this.

Lucky for you, you're not!

 

If possible get a Dodge or DeSoto junk head. Whichever has a bore closer to your Cad. Cut it up so that you can place one chamber on a Cad block at a time. It's good if you can see inside the chamber. Now try to visualize where your head bolts and pushrods will need to go. Drill holes in the piece if you need to for head bolts. Think about some cross between Johnny Bondos idea and just running pushrod from the existing lifters. Maybe something in the valve guide with a cup just below the deck will give you an angle that will work. It's good that some people are thinking about this. I thought about the Plymouth for years before cutting metal. I to heard that it wouldn't work. Wanna see the trophy?

 

I wanna see the trophy!

Great idea Rich!

Looks like I'll need a 241 Dodge Hemi Head-3.4375 bore- that's the closest. Ill try and find one!

Ok, rustybucket sent these files to me,in .jpg and .SLDPRT, based on the measurements of our current heads. I think between making this 'blank' head, and finding a Dodge 241 head, I can get the valve train pretty well figured out.

...maybe!

 

Ok, what's a 'wedge' head? Any pics of the valve alignment?


Ok, I've taken the search for info a little further, and you can find that info here:

http://www.jalopyjournal.com/forum/showthread.php?t=557169

And for those of you that don't know why I want to do this, you'll find the reason here:
http://www.jalopyjournal.com/forum/showthread.php?t=496866

.

 

Manche, I'm starting to like this idea!

Except, I think one big intake valve, and two smaller exhaust. The chamber diameter will be small-3.3", so this might work good. The Chamber is two small to get two valves in that are big enough, but this is one solution.

I've been looking at the Dodge slant 6, since cylinder bore diameter is close -3.4". The valve train would be far easier to set up than the Hemi 241!

 

If you plan to make a set plan on making 2, I want a set. I have no idea how to do what y'all are talking about and am not that machinist oriented, but I want a setup. If anyone can make it happen you can, and I'm serious put me down for order #1.

and hey I wont be racing ya with those small HP numbers, ha lol......

 

I think the plan is to have two intakes because the small ports promote high velocity and good cylinder filling at atmospheric pressure. With the pump I don't know. But if I had a choice I would go with the two intakes and have some heads with maximum versatility for future use.

 

Hello, I was just reading a HONK, Aug. 1953..Flathead Cad out of a tank was bored to 3 5/8 and the stroke was 4 1/2, total of 368 CIs.. A Winfield SU-1R cam actuates the valves. The heads were Cyclone with 8.6 to 1 compression..
Thought you might like some history on the Cad..
Duane.

 

Wyatt, when I get them done, you can have the set after the prototypes!

ya, I wish we could make REAL HP!

I'll research this further Rich. It's the only way I can see to get enough air in and out of those small chambers! Good thing is, on the dummy head, I can flowbench both and see how it works. I thought the huffer might be ok with one big intake, and get the gasses out quickly with two small ones.

...but I've learned that you're usually right!

Hi Duane!

Do you have any more info on that engine?

I'm surprised they went with the SU-1R, and not the 1A. I had both of those grinds for this engine, ground by Jim Brierly. He suggested the SU-1A for the stick, and the SU-1R for Keepers automatic.