HC Heads

S

saxman657

Member
I’ve recently come across a number of old cast iron heads, some of which seem to be in pretty good shape. All are cast with the information below on top of the head - if pictures of both top and bottom help, I have them. I’m hoping to get a bit more knowledgeable on what this fellow has: 1)Harry Miller, 2) Leon Duray, 3) Winfield 8069 (is this an 8:1?), 4) Winfield (a 7 on top is all I could see 7:1?), 5) Pop Evans Turbulence A-Head, 6)Burlington Heat (pat 1800188), Super Winfield. He also has several Riley Heads.

Note - I already have a cast iron 6:1 Winfield yellow head, but these other heads really intrigued me. Appreciate any thoughts or background that anyone might like to share.
 
Original Winfield heads were marked with a serial number but no other indication of the CR, so that 8069 is just the serial.
 
Without tons of research I don't have a good idea of these heads in my brain. Some photos would help.

Generally the higher the compression ratio the higher the torque. Horsepower is improved but without a high flow intake system, including carburetor(s), you are not going to get the best horsepower.

That said, the combustion chamber design is also important. It must allow free flow from the intake port to the cylinder with nicely contoured sections. The squish area should have a 1/16 gap between recess in the head and the piston.
 
Winfield combustion chambers were different between the 6:1 and 7:1 - not all 7:1 heads had Super cast into them. The Simmons had an unusual combustion chamber design. If I remember he paid Chrysler a fee to use the design.
A lot of the repro heads do not have the piston relief cut and you may have interference if your pistons protrude above the block. (Don't trust my memory on the Winfield compression ratios I put on the pix).
As has been mentioned combustion chamber design is critical. Flathead car engine production pretty much died in the 1950s. But the search for a better combustion chamber went on. Not by any automotive manufacturer but by Briggs & Stratton. Jim Brierley used some of the tricks they came up with when he designed his 7:1 head. His head also has a thicker deck and is taller allowing for improved water circulation.
 

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For what it is worth, the photo in the middle, the Winfield 7:1 head, is more like the high performance heads used by Harley Davidson and Briggs and Stratton. In my opinion that would provide the best performance of the 3. The Simmons head does have a good squish area design and the Crowfoot head has too sharp of an area area where the air turns down into the cylinder, also in my opinion. Plus, the Simmons head is shrouding the valves which would restrict flow.
 
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Just curious , but why is the ignition source and compression chamber not directly above the piston for better down force ?
 
headonz said:
Just curious , but why is the ignition source and compression chamber not directly above the piston for better down force ?
Click to expand...

That is a characteristic of all side valve engines. With the valves beside the cylinder, the head must cover them and the cylinder. There MUST be clearance around the valves for the gasses to enter and leave efficiently. That means there is a large chamber around them. If the chamber were to be enlarged so that the spark plug were over the cylinder, the compression ratio would be ridiculously low.
Side valve engines are less efficient than overhead valve ones but they are cheaper to make and restore, they are quieter and have fewer moving parts. Each has an advantage over the other IMO.
 
The basic head combustion chamber shape was designed by Ricardo in the 1920's. He did extensive tests to come up with his design. The squish area, the place between the top of the piston and the relief cut into the head, pushes high velocity air into the combustion chamber to provide lots of turbulence. That increases the speed of the burning of the air/fuel mixture for improved performance. The plug is usually placed in this turbulent environment. The combustion gasses must then move down into the cylinder to push on the piston. That is one reason why a generous radius is needed where the gasses turn down into the cylinder. Like all things that are Model A, it gets more complicated when you get into the details. A lot of smart engineers were involved in the design of the Model A.
 
Brierley’s combustion chamber was modeled after the Harley Davidson motor cycle racing heads
The effect of moving the spark plug closer to the bore shortens the fuel burn time as to reduce the amount of timing lead required

Additionally it is true that the depth of the chamber in the transition area between valves and bore does influence the airflow if you try to raise the CR too much

J
 
John, Some high ratio combustion chambers have a crown at the edge of the cylinder so that there is more room for combustion gasses to flow.
 
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