Need Valve Event Timing Advice
Thread Starter
TECH Enthusiast
Joined: Nov 2002
Posts: 593
Likes: 1
From: Chicago Heights, IL
Need Valve Event Timing Advice Lets say I had a cam that had valve events of:
Intake Valve opens - IVO 4 BTDC
Intake Valve closes - IVC 44 ABDC
Exhaust Valve Opens - EVO 46 BBDC
Exhaust Valve Closes - EVC -2 ATDC
Overlap 2 degrees
Now, lets say I know I am running .020" milled heads and I know my intake valve P/V clearance is tight, however I have plenty of clearance on the exhaust side.
So, I switch to a cam with these valve events:
Intake Valve opens - IVO 4 BTDC
Intake Valve closes - IVC 48 ABDC
Exhaust Valve Opens - EVO 56 BBDC
Exhaust Valve Closes - EVC 0 ATDC
Overalap 4 degrees
The Intake valve closing and exhaust valve opening would have no bearing in P/V clearance, but I am staying at the exact same intake valve opening position, and the exhaust valve closes 2 degree later than the original cam.
In theory, I shouldnt have any problems with P/V clearance, regardless of what the actual specs of the cam are....correct?
Intake Valve opens - IVO 4 BTDC
Intake Valve closes - IVC 44 ABDC
Exhaust Valve Opens - EVO 46 BBDC
Exhaust Valve Closes - EVC -2 ATDC
Overlap 2 degrees
Now, lets say I know I am running .020" milled heads and I know my intake valve P/V clearance is tight, however I have plenty of clearance on the exhaust side.
So, I switch to a cam with these valve events:
Intake Valve opens - IVO 4 BTDC
Intake Valve closes - IVC 48 ABDC
Exhaust Valve Opens - EVO 56 BBDC
Exhaust Valve Closes - EVC 0 ATDC
Overalap 4 degrees
The Intake valve closing and exhaust valve opening would have no bearing in P/V clearance, but I am staying at the exact same intake valve opening position, and the exhaust valve closes 2 degree later than the original cam.
In theory, I shouldnt have any problems with P/V clearance, regardless of what the actual specs of the cam are....correct?
It should work fine as long as the lift/degree ratio stays the same as the old intake lobe. Essentially you've switched to a longer duration and moved the centers apart. Should make for some great midrange and topend power. Acceleration suffers slightly.
Good luck,
Richard
Good luck,
Richard
Thread Starter
TECH Enthusiast
Joined: Nov 2002
Posts: 593
Likes: 1
From: Chicago Heights, IL
Originally Posted by Richard@WCCH
It should work fine as long as the lift/degree ratio stays the same as the old intake lobe. Essentially you've switched to a longer duration and moved the centers apart. Should make for some great midrange and topend power. Acceleration suffers slightly.
Good luck,
Richard
Good luck,
Richard
