HP & Torque For Various Cylinder Heads

Marshall may favor insert bearings. Did he say if he has pressurized lubrication?

IMHO Insert bearings by themselves have only a little to recommend over poured babbit. It offers a stiffer "substrate" as foundation for the babbit surface but you lose a little in "contouring" (bearing edge rounding to match the crank.) And possibly a little more in the groove normally provided for lubrication supply on an insert bearing.

NOW provide pressurized lubrication and both of these negatives go away. Pressurized lubrication theoretically supports the crank on a pressurized film of oil. In an ideal world the crank never touches the babbit. Introduce reality and yes touch is limited but not nearly continuous as it would be with hydrodynamic "gravity" lube.

Sorry. I did a undergrad level thesis paper on bearing lubrication "back in the day" for the BSME.

Joe K
 
Many years ago I ran my widebed on an electric duyno. Electric dynos have both advantages and dis-advantages over water-wheel dynos. At the time I was running a 2-port Riley (long before R2P) and power at the wheels was 60 hp. This was with an all babbitt 'C' engine, stock 'B' cam, glass-bowl Holley carb and B dist. and 7.5:1 compression. With the electric, you can drive the engine with the dyno, I pushed in the clutch, driving the entire drive-train (not the engine) and it took 25 hp, so adding the 60 at the wheels and the 25 meant approx. 85 hp at the flywheel. The 25 would be fairly consistant on all cars using a V8 trans and stock A rear end. My memory is not so good but my speedster on the chassis dyno in Lincoln, NE peaked at 3900 RPM. All babbitt, dip and splash oiling, three 81 carbs, 6:1 Winfield, mild-performance cam, stock sized valves. HP not remembered but think about 90. I have run 167 MPH on babbitt mains and 135 on babbitt rods with full pressure oiling, no failures but mains hold up better than rods. Never any head gasket problems! Babbitt is good, detonation is very bad.
 
Jim Brierley said:
Many years ago I ran my widebed on an electric duyno. Electric dynos have both advantages and dis-advantages over water-wheel dynos. At the time I was running a 2-port Riley (long before R2P) and power at the wheels was 60 hp. This was with an all babbitt 'C' engine, stock 'B' cam, glass-bowl Holley carb and B dist. and 7.5:1 compression. With the electric, you can drive the engine with the dyno, I pushed in the clutch, driving the entire drive-train (not the engine) and it took 25 hp, so adding the 60 at the wheels and the 25 meant approx. 85 hp at the flywheel. The 25 would be fairly consistant on all cars using a V8 trans and stock A rear end. My memory is not so good but my speedster on the chassis dyno in Lincoln, NE peaked at 3900 RPM. All babbitt, dip and splash oiling, three 81 carbs, 6:1 Winfield, mild-performance cam, stock sized valves. HP not remembered but think about 90. I have run 167 MPH on babbitt mains and 135 on babbitt rods with full pressure oiling, no failures but mains hold up better than rods. Never any head gasket problems! Babbitt is good, detonation is very bad.
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Jim, What is your experience with Snyder's 5.5 and 6 heads? Can you see a reason why someone would opt for 5.5 over 6?
 
I have very little experience with any stock-looking head. I have a friend that ran a 5.5, then milled all the relief off, and was/is very pleased with it. I don't know what the ratio is after doing that. I would choose the 6:1. Be careful milling all the frelief off as stock pistons protrude above the block and could hit the head.
 
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I am running a 7:1 Winfield and am very happy with it. I had a lot of trouble with pinking in the early days whilst using an original distributor but since changing to a Mallory the problem has been solved. It would appear that the shape of the combustion chamber has some bearing on the performance and pinking, as a Fraser Nash, raced in the UK with a Model A engine was plagued by pinking issues until he changed to a Winfield head.
 
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