SOHC for LS
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When the SR-71 was retired in 1990, one Blackbird was flown from its birthplace at United States Air Force Plant 42 in Palmdale, California, to go on exhibit at what is now the Smithsonian Institution's Steven F. Udvar-Hazy Center in Chantilly, Virginia. On 6 March 1990, Lt. Col. Raymond E. Yeilding and Lt. Col. Joseph T. Vida piloted SR-71 S/N 61-7972 on its final Senior Crown flight and set four new speed records in the process:
- Los Angeles, California, to Washington, D.C., distance 2,299.7 miles (3,701.0 km), average speed 2,144.8 miles per hour (3,451.7 km/h), and an elapsed time of 64 minutes 20 seconds.
- West Coast to East Coast, distance 2,404 miles (3,869 km), average speed 2,124.5 miles per hour (3,419.1 km/h), and an elapsed time of 67 minutes 54 seconds.
- Kansas City, Missouri, to Washington, D.C., distance 942 miles (1,516 km), average speed 2,176 miles per hour (3,502 km/h), and an elapsed time of 25 minutes 59 seconds.
- St. Louis, Missouri, to Cincinnati, Ohio, distance 311.4 miles (501.1 km), average speed 2,189.9 miles per hour (3,524.3 km/h), and an elapsed time of 8 minutes 32 seconds.
I haven't heard of any methodology concerning that, and I believe that will be a stumbling block that can only be solved by overcomplexity, which I KNOW you'd prefer to avoid like the plague.
As they expand, we will have to measure what that is. It’s not like the camshaft EVER becomes unloaded, so even a “significant” lash shouldn’t mean that the gears are bouncing around.
Again, thankfully, this is something largely external to the engine design, and can be shafts / bevel gears like the old WW2 piston aircraft engines, or belts, or spur gears, or chains.
As they expand, we will have to measure what that is. It’s not like the camshaft EVER becomes unloaded, so even a “significant” lash shouldn’t mean that the gears are bouncing around.
Again, thankfully, this is something largely external to the engine design, and can be shafts / bevel gears like the old WW2 piston aircraft engines, or belts, or spur gears, or chains.
I suspect that cost, cost, and cost are the three reasons why manufacturers revert back to pushrods / rockers and a single camshaft. NASCAR engines with pushrods just appeal to the same crowd that likes Harley Davidson motorcycles. Not because there is some nirvana to be achieved.
One thing I remain steadfast on… things that are NOT in the design 1) do not break, 2) do not weigh anything, 3) cost nothing.
It’s why there’s not 3 or more valves per cylinder, or DOHC. Don’t need it, it adds complexity and usually adds weight, and it’s more things to break.
We don’t really have cost issues, at least not in the same way most automotive consumers might think. The market for this engine is 100 to 1000 units. It’s a niche, in a niche. The manufacturing costs will be absurd, simply because of the low volume. The sales price of the competing engine, new, is $150,000. Engines with close to the power that we envision (500 hp) cost $250,000 now (Lycoming IO-720, only 400 hp).
It’s designed to replace 60+ year old engine designs, with something MORE reliable and more powerful, while eliminating most of the issues present in air cooled designs without computer controls, designed with 1940’s methodology.
EDIT: Let me know when Formula 1, Toyota, Honda, or any other world wide auto engine company (besides US) switch from OHC to pushrods. Thanks.
Last edited by TonyWilliams; Jan 20, 2025 at 02:43 PM.
I helped ProStockPaul STOP his AirCups from leaking, my method is used TODAY on F-1 engines.
Next engine used a TWO rocker arm/flower, one to open and one to close method.
Name that engine Tony ?
I suspect that cost, cost, and cost are the three reasons why manufacturers revert back to pushrods / rockers and a single camshaft. NASCAR engines with pushrods just appeal to the same crowd that likes Harley Davidson motorcycles. Not because there is some nirvana to be achieved.
One thing I remain steadfast on… things that are NOT in the design 1) do not break, 2) do not weigh anything, 3) cost nothing.
It’s why there’s not 3 or more valves per cylinder, or DOHC. Don’t need it, it adds complexity and usually adds weight, and it’s more things to break.
We don’t really have cost issues, at least not in the same way most automotive consumers might think. The market for this engine is 100 to 1000 units. It’s a niche, in a niche. The manufacturing costs will be absurd, simply because of the low volume. The sales price of the competing engine, new, is $150,000. Engines with close to the power that we envision (500 hp) cost $250,000 now (Lycoming IO-720, only 400 hp).
It’s designed to replace 60+ year old engine designs, with something MORE reliable and more powerful, while eliminating most of the issues present in air cooled designs without computer controls, designed with 1940’s methodology.
The one thing that could be addressed within the long block is a good balance job, both dynamic and static. That, plus possibly closer attention to assembly detail, and the blanket inclusion of roller lifters across the board.
Externally, a good basic but well-tuned EFI system, plus a good coil on plug ignition would solve most operational issues.
Nothing wrong with 60-70 year old designs IF they are good designs. The Lycoming, for example, needs refinement, not a total redesign. Even to the extent of including liquid cooling. That plus aforementioned EFI and coil on plug ignition (even dual if they insist) would keep it relevant.
I think your clean-sheet design is going to end up costing far more than $150k once all development AND certification costs are figured in. Clean sheet designs are never cheaper than legacy items, historically speaking.
The Best V8 Stories One Small Block at Time
I wouldn’t waste my time trying to hodgepodge a liquid cooling system on something that was designed to be air cooled.
Yes, it will cost plenty. It will be cheaper than turbines, GUARANTEED>
Last edited by TonyWilliams; Jan 20, 2025 at 09:44 PM.
The compound turbo (130 octane fuel) was tested in the Boeing pressure chamber.
Would you try this method?
Lance
Budget is $15 million for 100 engines.
Last edited by TonyWilliams; Jan 21, 2025 at 01:46 PM.









