Bruce Crower High CR/Late Intake Valve Closing Engine
- Thread starter Soldmy66
- Start date
Do a internet search using "Bruce Crower High CR/Late Intake Valve Closing Engine"
And you will be amazed at the number of results. Many of the results are forums and there is plenty of info.
You have me curious as well. I don't have time at the moment to look at them but i wll later.
And you will be amazed at the number of results. Many of the results are forums and there is plenty of info.
You have me curious as well. I don't have time at the moment to look at them but i wll later.
You might want to search "Miller Cycle" as well. Same principles involved except that Miller cycle engines are normally supercharged.
Sounds like Larry Widmer and Bruce Crower and the Miller Bros learned from engines the most important lesson..non direct injected gasoline engines are detonation limited.
See Widmers Soft Head/ RollerWave engines, either supercharged or non supercharged. http://www.hotrod.com/featuredvehicles/ ... _civic_si/
The soft head gospel is a lot like Crower and Millers, and its all about reverse engineering from a maximum detonation point. The cam became the whole reverse engineering inflection point. Australian Sam Blumstien said it best...there are no wrong cam selections, only wrong engine combinations. Because canted valve engines like the 335 and 385 Fords are great power producers, but poor detonation survivers, that's the kind of engine Widmer majored in. A super charger 50% of the engine size, an 11:1 or 14:1 to 16:1 non s/c compression ratio, and aspirations ratios down to 3300 on a normally aspirated V8...6% more specific power than a NASCAR V8, with 20% less cam duration.
See http://mpgresearch.com/discussion/1985- ... -soft-head
Anyway, the combo's were emission compliant, but the piston design was very specific, a lot like Fords direct injection stratified charge ProCo" (programmed combustion)engines, and as a custom engine, likely to be a sucess, but as a production engine, a bit of a commerical risk.
See Widmers Soft Head/ RollerWave engines, either supercharged or non supercharged. http://www.hotrod.com/featuredvehicles/ ... _civic_si/
The soft head gospel is a lot like Crower and Millers, and its all about reverse engineering from a maximum detonation point. The cam became the whole reverse engineering inflection point. Australian Sam Blumstien said it best...there are no wrong cam selections, only wrong engine combinations. Because canted valve engines like the 335 and 385 Fords are great power producers, but poor detonation survivers, that's the kind of engine Widmer majored in. A super charger 50% of the engine size, an 11:1 or 14:1 to 16:1 non s/c compression ratio, and aspirations ratios down to 3300 on a normally aspirated V8...6% more specific power than a NASCAR V8, with 20% less cam duration.
See http://mpgresearch.com/discussion/1985- ... -soft-head
Anyway, the combo's were emission compliant, but the piston design was very specific, a lot like Fords direct injection stratified charge ProCo" (programmed combustion)engines, and as a custom engine, likely to be a sucess, but as a production engine, a bit of a commerical risk.
It is the Atkinson cycle.
I remember the Hot rod article. It was around the time of the oil-embargo.
The goal was to increase the thermal efficiency for the sake of better gas mileage by using a high static compression ratio while lowering the dynamic compression ratio below detonation limits with a late closing intake valve.
In the late 70s Crowe designed a cam with a late closing intake for the SBC and offered a kit including high compression pistons.
Hot rod screwed up the test by not taking the time to tune the carb or the ignition timing.
I remember the Hot rod article. It was around the time of the oil-embargo.
The goal was to increase the thermal efficiency for the sake of better gas mileage by using a high static compression ratio while lowering the dynamic compression ratio below detonation limits with a late closing intake valve.
In the late 70s Crowe designed a cam with a late closing intake for the SBC and offered a kit including high compression pistons.
Hot rod screwed up the test by not taking the time to tune the carb or the ignition timing.
