Speed-Talk is running on www.Speed-Talk.com

IMPORTANT: Update your bookmarks to https://www.speed-talk.com/forum/
(Right-click the URL and select "Bookmark this link")

Evolving the Side valve flat head design idea

Engine tech, for those engines, products, and technologies of yesteryear.

Moderator: Team

Nikolas Ojala
Pro
Pro
Posts: 340
Joined: Sat May 03, 2014 11:57 pm
Location: Finland

Re: Evolving the Side valve flat head design idea

Post by Nikolas Ojala »

frnkeore wrote: Sun Jul 19, 2020 3:00 am
How about a Roller cam, 452 CI, OHV Cad V16?
Nope. Different animal.
Nikolas Ojala
Pro
Pro
Posts: 340
Joined: Sat May 03, 2014 11:57 pm
Location: Finland

Re: Evolving the Side valve flat head design idea

Post by Nikolas Ojala »

Nikolas Ojala wrote: Fri Jan 03, 2020 7:02 pm
I'd like to see drawings of Cadillac V-16 flathead engine. Anyone?
I found what I was looking for.
Cadillac_V-16.jpg
You do not have the required permissions to view the files attached to this post.
frnkeore
Pro
Pro
Posts: 275
Joined: Wed Dec 25, 2019 3:06 am
Location: Oregon

Re: Evolving the Side valve flat head design idea

Post by frnkeore »

Great. I had the opportunity to see the OHV version, in '62 or '63, when I was 18 but, I can't remember ever seeing the FH.

It would be interesting to know why the change. I would guess the reason was cost, as the OHV has more power potential. But, sadly, either last very long.
Nikolas Ojala
Pro
Pro
Posts: 340
Joined: Sat May 03, 2014 11:57 pm
Location: Finland

Re: Evolving the Side valve flat head design idea

Post by Nikolas Ojala »

frnkeore wrote: Thu Jul 30, 2020 1:56 pm
It would be interesting to know why the change.
The V-12 was definitely not necessary, since the V-8 developed almost as much power. Another factor was that an all-new body had been scheduled – the long, high, ohv V-16 didn't fit into the picture. Thus, the higher-ups decided on a new L-head V-16 with a 135-degree vee. This new engine, with a square bore and stroke of 3¾ inches, nine-bearing crankshaft, and piston travel of only 1590 feet per mile (with the 4.31-to-1 axle) proved to have remarkable durability, smoothness, and flexibility from any speed on up beyond 100 mph. In comparing it with the ohv V-16, it was nearly six inches shorter, 12 inches lower, 4⅜ inches wider, 250 pounds lighter, and had slightly less than half as many parts. The new engine weighed only 120 pounds more than the 1937 V-8 as used in the Series 75 limousine.
Source: http://wildaboutcarsonline.com/members/ ... ct_1-6.pdf
frnkeore
Pro
Pro
Posts: 275
Joined: Wed Dec 25, 2019 3:06 am
Location: Oregon

Re: Evolving the Side valve flat head design idea

Post by frnkeore »

Thank you for that. It was a great article.
Nikolas Ojala
Pro
Pro
Posts: 340
Joined: Sat May 03, 2014 11:57 pm
Location: Finland

Re: Evolving the Side valve flat head design idea

Post by Nikolas Ojala »

The drawing shows easily what kind of benefits there are available if the flathead engine is either inline or the V-angle between cylinder banks is wide. Both intake and exhaust manifolds may be built on the same side, and there is no need to arrange exhaust ports between cylinders, which would require a longer block. Instead, both intake and exhaust ports are short, and there is some space available for optimizing intake manifold. 
 
Cadillac_V-16_drawing.png
 
 
Now one could marvel if the engine was a flat-twelve instead of V-16. The angle between cylinder banks would be 180° and balance would be same way natural as in straight-six engines. With modern design tools and other modern equipment the manifolds could be arranged better, and also drys sump could reduce total height. The whole engine could be really flat.
You do not have the required permissions to view the files attached to this post.
PackardV8
Guru
Guru
Posts: 6245
Joined: Sun Jul 30, 2006 2:03 pm
Location:

Re: Evolving the Side valve flat head design idea

Post by PackardV8 »

I've worked on that wide angle Cad and on the narrow angle Auburn/American LaFrance V12. Both are interesting. Neither make enough horsepower to overcome the inherent limitations of the side-valve.
Jack Vines
Studebaker-Packard V8 Limited
Obsolete Engineering
Nikolas Ojala
Pro
Pro
Posts: 340
Joined: Sat May 03, 2014 11:57 pm
Location: Finland

Re: Evolving the Side valve flat head design idea

Post by Nikolas Ojala »

PackardV8 wrote: Thu Jul 30, 2020 9:53 pm  
Neither make enough horsepower to overcome the inherent limitations of the side-valve.
 
 
Yes, flatheads do not breathe well.
 
I think that most interesting is the hint revealed by Barney Navarro. He said that with high dome pistons and with compatible heads the flow rate could be increased perhaps three times bigger than with conventional low flat top pistons. Three times flow means three times power. I just don't know has this been verified and published anywhere. Until someone does verify, we just don't know. I suppose that flow simulation should also give some results.
Received from Barney Navarro          Jan. 27, 2002
 
I wish to add some information and corrections to the discussion about Pop-Up Piston Design for Flathead Ford V8 engines. Tony Baron’s father, Frank and his Uncle Bob Tattersfield, were both friends of mine in the manufacturing era immediately after World War II. It is correct that they were the first to make a commercial venture of pop-up cylinder heads, but I think there were others who used the principle on an individual basis. It should be noted that I do not call my heads pop-ups; they are listed as Hi DOME HIGH FLOW CYLINDER HEADS.
 
The problem of insufficient compression potential in flathead engines has been around longer than any of the now living enthusiasts. Sir Harry Ricardo probably came up with the first good solution that did not require a special piston configuration; the cow hoof shaped re-entrance baffle. Ed Winfield, who became famous for his wonderful carburetors and cam grinding, used the Ricardo chamber in his first production run of high compression heads for Model A Fords. It was with great chagrin that he found it necessary to change design because the Ricardo patent was still in effect at that time and Chrysler owned the patent.
 
When I made the drawings for my cylinder heads, I felt that the hoof shaped re-entrance baffle would provide the highest compression and highest air flow. A subsequent test by Marlo Pichel using his dyno and air flow measuring system proved the validity of the design. Mike Davidson, the Australian who wrote a book on flatheads, shows a higher air flow rate for those originals than all the other popular heads that don’t require special pistons.
 
Fifty years ago when many of the hot track roadster drivers were running engines with “pop-ups”, that configuration became the “in thing”. I tried the idea also, but the amount of piston projection above the block deck was only 3/8 of an inch. That small distance did not increase the crossectional area of the transfer region sufficiently to make a noticeable increase in performance. As many of us did in those days, I consulted with Ed Winfield. In our conversation, he brought up the shape of a piston in a Miller; he would never bend enough to call those engines Offys. Now what possible relationship could a dual overhead cam’s pistons have to a flathead Ford? Simply this: that big lump of heat absorbing aluminum subtracts from heat of the combustion gasses that help to push the piston down. Winfield agitated for a smaller included angle between the intake and exhaust valves of those engines until Art Sparks pushed the idea and took the undeserved credit for the concept. After hearing Winfield use the Miller piston as a horrible example, I didn’t need to ask any questions about Miller and flathead Ford relationships.
 
In the reasoning process that caused me to use the same radius dome as the early Chrysler hemi, I kept in mind a number of factors that had a bearing on the final choice. Winfield’s lump comment stood foremost in my field of vision. This led me to think that extending the piston’s major diameter into the cylinder head was not the best idea. Since a spherical or ball shape can enclose the most volume for a given surface area the Hemi shape won out. The use of the same radius as the Chrysler should not infer any magical or “trick” connotation. It just so happened that I had a doming cutter from a pair of Chrysler hemi aluminum heads that I made for Henry Kaiser in 1957.
 
C. R. Axtell, many years before the birth of the high domes using the Chrysler radius of 3.305”, often bugged me to make my heads with a pop-up configuration. He cited some air flow work he had done on a 45 cubic inch Harley Davidson flathead motorcycle engine. That little engine produced 60 horsepower. How would you like to get a horsepower to cubic inch ratio like that in your flathead Ford?
 
Axtell described the Harley combustion chamber quite thoroughly, even down to the little triangular peninsular projection between the intake and exhaust valve. Testing had demonstrated that it did not impede air flow, so it was inserted to help the compression ratio. Another aid to compression is the island over the exhaust valve. No matter how much you are able to whittle my high dome heads or anyone else heads, the Harley cannot be matched because of stud and water hole locations in the Ford block.
 
When Tom Gerardi first entered my shop, he asked me if I was interested in up-dating my cylinder heads. I told him that I was very interested if someone had a car or was building one to establish some kind of record. Tom showed a great deal of enthusiasm and assured me that he was my man. I told him about the information I had received from C. R. Axtell and showed him the extra core boxes for the water jacket cores and combustion chambers. I had some of the essential parts for a flow bench since I needed one to further refine an air flow measuring fuel injection that I developed for my Indy car. Prior testing of that injection system was done at Garrett AiResearch, the turbocharger manufacturer.
 
When the flow bench finally reached a usable condition, I took one of my standard nostalgia heads and cut a flat dome 11/16 of an inch deep. Of course this destroyed the head for any engine installation. What was accomplished was to produce a cavity that could be partially filled with clay. There were many tasks for me to address to keep my shop functioning, so I was pleased to have Tom run the flow bench at my direction. Templates were made to scrape away unwanted clay and to produce the desired curvatures. The 3.305” radius dome was compared with the flat dome and was found to be slightly inferior. There wasn’t a great difference, but it was observable. Until some dyno testing is done no one can positively say one is better than the other. As for Tom’s assertion that the air flow rate had been increased to three times what is was when we started; reflect on this - three times the air would result in three times the horsepower. Applying a claim of such magnitude to a 200 horsepower flathead would mean that you would get 600. When casting time rolled around, four flat dome heads were made. Tom took two for future dyno comparisons with the round dome type. Since Tom became a trader, instead of a racer, a car never materialized. He sold the flat toppers to someone in Oregon and the other two heads stayed on my shelf until recently. Tom purchased four pairs of heads and sold them through advertisements in Hemmings. At $350.00 per pair, during the loss leader introductory period, his friends were expecting an impossible discount.
 
The most interesting part of this saga took place shortly after flow bench testing started. Tom came to my shop with a couple of drawings illustrating a plan view and cross section of the Harley combustion chamber; of course we couldn’t use them because of the dimensional differences from a Ford. What was really accomplished with the drawings was to confirm Axtell’s description.
 
My choice of the hemi-type dome for production is based on the possibility of too much heat loss from the portion of the flat top piston projecting above the block deck. The second objection, is the dead gas space between the piston crown and extension of the block’s cylinder wall that extends into the head. The only way that this question can be resolved is through an unbiased dyno test.
 
As for someone taking over the production of my equipment in the very near future, I haven’t had anyone approach me with a BIG ROLL OF GREEN. My patterns and core boxes are not wooden with wax filets, like the competition, so someone attempting to duplicate casting quality without my foundry equipment would find it impossible.
 
Source to the quoted text above: https://web.archive.org/web/20030518034 ... avarro.htm
Nikolas Ojala
Pro
Pro
Posts: 340
Joined: Sat May 03, 2014 11:57 pm
Location: Finland

Re: Evolving the Side valve flat head design idea

Post by Nikolas Ojala »

There is another and obviously more recent source that claims only 30% increase which is still quite much and easier to accept than 300% as in previous quote.
 
This design, along with the pad over the exhaust valve allows for good compression along with excellent breathing characteristics. These features along with larger valves, radiusing the combustion chamber walls behind the intake valves and filling a portion of the valve bowl, produces over 30% more airflow and a similar resultant gain in horsepower. A 2-pattern cam should be used with these heads since the 1 1/2" exhaust valve doesn't have to open 7/16 to 1/2" like big intake valves. 
 
Source: https://web.archive.org/web/20190301201 ... _dome.html
frnkeore
Pro
Pro
Posts: 275
Joined: Wed Dec 25, 2019 3:06 am
Location: Oregon

Re: Evolving the Side valve flat head design idea

Post by frnkeore »

The only way that I can see a flat head type engine breathing, would be in the T configuration, with 4 valve per cylinder. That requires 2 cams for inline engines but 3 cams for a V. But, I don't know how you could developed compression with that design. It might also require dual spark plugs.

Besides the 90 deg flow path (180 total), you only get about a 180 deg, flow curtain, at best. A T combustion chamber, with a highly boosted turbo might be a option for power but, it still wouldn't keep up with a pentroof 4V.
learner1
Member
Member
Posts: 55
Joined: Sun Apr 17, 2016 2:15 am
Location:

Re: Evolving the Side valve flat head design idea

Post by learner1 »

I can't see a 3x flow rate improvement with out changing to an OHV design. I think most of the gains will come from improving the combustion efficiency on these engines.
PackardV8
Guru
Guru
Posts: 6245
Joined: Sun Jul 30, 2006 2:03 pm
Location:

Re: Evolving the Side valve flat head design idea

Post by PackardV8 »

I think I mentioned a conversation with the Harley KR guys toward the end of development. Their bottom line, "The tradeoff and ultimate limit in flathead horsepower is you can get a flathead to breathe or you can make compression. You can't do both." The best factory race engines were always between 6.3 to 7.2 compression, depending on the track.

Image

300% is ridiculous and 30% isn't possible either
Barney Navarro . . . said that with high dome pistons and with compatible heads the flow rate could be increased
Guarantee the H-D race team tried every conceivable piston and dome and found it just wasn't so. Still, slightly better than one horsepower per cubic inch is good flathead numbers. By the end, the best engines were making 48 hp @ 6,800 RPM from 45".

Lagniappe: Mert Lawwill won the finale for the KR with the 1969 Grand National Championship. “That was one of my all-time favorite bikes,” he says. “It had a soft kind of power you could really control on the dirt. Because the KR wouldn't breathe on the top end, it had a wide, flat power band. Even being allowed 750cc, the KR wouldn't make as much power as the better 500cc OHV Triumphs and BSAs, but to make their horsepower, it had to be all at the top end. I was always amazed that Gary Nixon could control his Triumph on the dirt, because the throttle was almost like an ON/OFF switch."
Jack Vines
Studebaker-Packard V8 Limited
Obsolete Engineering
Truckedup
Guru
Guru
Posts: 2490
Joined: Mon Jan 21, 2013 2:41 pm
Location: Finger Lakes

Re: Evolving the Side valve flat head design idea

Post by Truckedup »

PackardV8 wrote: Fri Jul 31, 2020 5:13 pm

Lagniappe: Mert Lawwill won the finale for the KR with the 1969 Grand National Championship. “That was one of my all-time favorite bikes,” he says. “It had a soft kind of power you could really control on the dirt. Because the KR wouldn't breathe on the top end, it had a wide, flat power band. Even being allowed 750cc, the KR wouldn't make as much power as the better 500cc OHV Triumphs and BSAs, but to make their horsepower, it had to be all at the top end. I was always amazed that Gary Nixon could control his Triumph on the dirt, because the throttle was almost like an ON/OFF switch."
The Harley has better traction on dirt tracks
with its 405-270 crank compared to the Triumph 360 degree crank. But those flat head dinosaurs put one good race..
Gary Nixon has broken his hand in a crash and the next week was a race he had to win...He could not control the throttle with hand in a cast..His mechanic wired the throttle wide open and Nixon used the the kill switch to control speed going into the turns. He won....
Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire
PackardV8
Guru
Guru
Posts: 6245
Joined: Sun Jul 30, 2006 2:03 pm
Location:

Re: Evolving the Side valve flat head design idea

Post by PackardV8 »

The greatest tribute to Garry Nixon came from Dick O'Brien, the H-D factory racing chief.
"We have the best machines, spend the most money, try to get the best riders and that little-red-headed-shit comes out and blows off all of us - with fifteen less horsepower."
Jack Vines
Studebaker-Packard V8 Limited
Obsolete Engineering
Pete1
Member
Member
Posts: 71
Joined: Sun Nov 10, 2013 9:41 pm
Location:

Re: Evolving the Side valve flat head design idea

Post by Pete1 »

I often wonder why H-D when they had an almost unlimited development budget, didn't think about bigger ports and valves.
While bigger is sometimes slower flow with N/A, on a flathead Ford it means more hp if the volume goes up. We did flow testing back in the late 50's with
ports enlarged by welding steel tubing in machined out blocks and the bigger we went the bigger the dyno numbers.
Ron Main found this in later years by going over 300 with a flathead.
Post Reply