CLASS RACER FORUM - View Single Post - Valve Spring Pressure

Darrin Christen · 06-28-2018, 05:32 PM

[/QUOTE]I do not use clay to check. I check as run, complete the springs. Manley makes a tool to open the valve using the rocker arm. Check every 2 degrees between 25 degrees BTDC and 25 degrees ATDC. Your piston to valve clearance, as run, should be equal to or greater than your TOTAL piston to deck clearance. On the exhaust, you need 0.075", checked the same way.
Alan,
I know many people use this method for checking ptvc, but when you open the valve using the rocker arm to find the clearance you basically take all of the load off of the pushrod and lifter which doesn't account for any pushrod flex. Seems to defeat the purpose of checking the clearance in an as run situation. I do realize that the larger diameter and thicker wall pushrods would have minimal flex. Just a thought.

06-28-2018, 05:32 PM	#26
Darrin Christen Member Join Date: Mar 2007 Location: Des Allemands, LA Posts: 365 Likes: 8 Liked 1 Time in 1 Post	Re: Valve Spring Pressure - BBC stocker [/QUOTE]I do not use clay to check. I check as run, complete the springs. Manley makes a tool to open the valve using the rocker arm. Check every 2 degrees between 25 degrees BTDC and 25 degrees ATDC. Your piston to valve clearance, as run, should be equal to or greater than your TOTAL piston to deck clearance. On the exhaust, you need 0.075", checked the same way. Alan, I know many people use this method for checking ptvc, but when you open the valve using the rocker arm to find the clearance you basically take all of the load off of the pushrod and lifter which doesn't account for any pushrod flex. Seems to defeat the purpose of checking the clearance in an as run situation. I do realize that the larger diameter and thicker wall pushrods would have minimal flex. Just a thought. __________________ 4878 SS/GA 66CHEVY II