MustangWorks.com : Ford Forums - View Single Post - The Camshaft Spec "lobe Center" What Does It Mean As Far As "effect" On Performa

ballistic_331LX · 06-10-2002, 01:10 AM

Hey man whats up...please read....i dug deep for this and have read it several times in the past...good luck
LOBE CENTER LINE
Lobe center line, or lobe centers, is the number of degrees between the theoretical center line of the exhaust and intake lobe for a given cylinder, measured in camshaft degrees. On automotive applications the average lobe center is 110°, but will vary between 118° and 100° depending on the application.
The lobe center line of the American automotive camshaft is determined at the time the camshaft is ground and cannot be changed except by regrinding the camshaft.
Contrary to what some cam manufacturers say, very minor changes in lobe centers can alter the power range of an engine sufficiently to make a winner out of an also ran. Subtle changes in lobe centers are one of the top secrets of the successful cam designer. To decrease the lobe centers of a given camshaft, the exhaust lobe would be retarded and the intake lobe advanced. This would cause the exhaust to open later and close later and the intake to open earlier and close earlier.
A camshaft with closer lobe centers will have more overlap (valves
open more at TDC at start of intake stroke) and higher cylinder
pressure due primarily to the earlier closing. The camshaft with the closer lobe centers will always produce more power in the mid range than a cam using the same profile and wide lobe center, and in many applications will produce more power all throughout the range depending on many variables such as the induction system, rod angularity and flow capacity of the ports.
The full potential of lobe center changes can only be appreciated by someone who has had the opportunity to work with an engine that is equipped with a separate cam for intake and exhaust such as the Offy, Jag, four cam Ford, etc. Until a person has been able to change lobe centers at will, he cannot fully appreciate the affects on performance.

06-10-2002, 01:10 AM	#2
ballistic_331LX Registered Member Join Date: Jun 2002 Posts: 28	lobe center.....you gotta comprehend this.....or it will lose ya!!! Hey man whats up...please read....i dug deep for this and have read it several times in the past...good luck LOBE CENTER LINE Lobe center line, or lobe centers, is the number of degrees between the theoretical center line of the exhaust and intake lobe for a given cylinder, measured in camshaft degrees. On automotive applications the average lobe center is 110°, but will vary between 118° and 100° depending on the application. The lobe center line of the American automotive camshaft is determined at the time the camshaft is ground and cannot be changed except by regrinding the camshaft. Contrary to what some cam manufacturers say, very minor changes in lobe centers can alter the power range of an engine sufficiently to make a winner out of an also ran. Subtle changes in lobe centers are one of the top secrets of the successful cam designer. To decrease the lobe centers of a given camshaft, the exhaust lobe would be retarded and the intake lobe advanced. This would cause the exhaust to open later and close later and the intake to open earlier and close earlier. A camshaft with closer lobe centers will have more overlap (valves open more at TDC at start of intake stroke) and higher cylinder pressure due primarily to the earlier closing. The camshaft with the closer lobe centers will always produce more power in the mid range than a cam using the same profile and wide lobe center, and in many applications will produce more power all throughout the range depending on many variables such as the induction system, rod angularity and flow capacity of the ports. The full potential of lobe center changes can only be appreciated by someone who has had the opportunity to work with an engine that is equipped with a separate cam for intake and exhaust such as the Offy, Jag, four cam Ford, etc. Until a person has been able to change lobe centers at will, he cannot fully appreciate the affects on performance.