New camshaft availability

Terry-"duration with valves seated" is not very informative without knowing the valve lash. Also, it would be usefull to know the duration at .050 as it is a big help in comparing to other cams. Thanks!
 
Amen Dan,
Also the timing events would be real helpful. Seat to seat numbers as well as those
at .050

Thanks
 
Picking a street cam is like getting an in depth medical diagnosis. If the buyer/user is to be completely happy, they need to first understand how cams work. They need to be aware that one cam will NOT be optimum for all driving conditions. They need to be aware what is going on in the engine while they are driving as they do. A cam that delivers the best gas mileage at highway speeds will not be best for parades or slow around town driving. A cam that has a lopey drive-in idle will not be good for slow driving. ETC ETC.
Most people are not interested in the basic engineering principles that go in to cam design because it requires a lot of math and engine design knowledge.
People that build race engines will have the necessary knowledge to choose a proper cam for a certain application. People concerned with street engines can rely on the person supplying the cam to tell them what they need by simply telling them what they use the car for.
Knowledge is good but not always useful....
 
Not applicable for a Model A but there is such a thing as a variable timing camshaft. It uses a roller follower and has a different profile along the length of each cam. The camshaft is moved in and out to change which part of the profile is active at each engine rpm. I think that race cars have solenoid activated valves so that the timing can be changed using an engine management computer. I could be wrong.
 
nkaminar said:
Not applicable for a Model A but there is such a thing as a variable timing camshaft. It uses a roller follower and has a different profile along the length of each cam. The camshaft is moved in and out to change which part of the profile is active at each engine rpm. I think that race cars have solenoid activated valves so that the timing can be changed using an engine management computer. I could be wrong.
Click to expand...

Some very large diesel engines use the sliding cam principle for direct reversing the engine, like in a tug boat application. The forward and reverse set of lobes are adjacent on the cam and the area between them is filed in like a smooth hill. When the engine is reversed, the cam is slid back and the roller followers just roll over the filled in area back to the next set of lobes.
The engine is air started so can make extremely quick reversals.

Formula one race engines have had pneumatic valve systems for several years. RPM is the only way a small engine can get the horsepower they do.
They can turn over 20K rpm.
Somewhere on youtube there is a video of a Renault F1 engine on the dyno turning 20K.. On those dyno's they can simulate an actual lap on a race course.
 
Race technology has made it to production cars in the form of DOHC designs.
The beauty of this is that the lobe centers can be changed on the running engine at will, or as programmed by the EFI. This results in extended torque range low and high RPM.

As Pete has mentioned, the induction and port design of a motor will dictate the cam requirements and with all of the options for heads available, flat head, F head and full OHV no cam will suit all. They will all run, but not to the full potential of the motor.

Modern engines can get 1 hp per cu in of displacement pretty easy.
Getting the same out of a Model "A" is a bit difficult, getting 1.5 can be done without a turbo or blower but you have to work for it, a lot of work.

Yes, the older V10 F1 motors were a really awesome, now V6 with electric blower and regen electric motor in the drive. What is really impressive now is the life span of the motors, limited number for the season allowed.

John
 
Bruce,

Yeah that was a few years ahead of its time, aluminum bores and all.

Now technology in racing uses a nickasil or plasma coating on the aluminum block, no cast iron liners.

Let's ask, when was the first DOHC race engine designed and built?

Best, J
 
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