Not when the whole thing is running.
Do all measurement at the lifter..... Push rod tip.
Turn the crank only one way. Normal running rotation direction.
Randy will attempt to oppose anythibg I post. Just for the sake of that.
Cylinder pressure and advancing cam timing.
Moderator: Team
Re: Cylinder pressure and advancing cam timing.
All you are getting for info from reading off the valve (retainer) is gobbledegoop. Garbage in garbage out.
Yoy must verrify true tdc with a piston stop first
Can be with heads on. Then do all event readings at the lifter.. Push rod tip is acceptable.
.050" at the valve is not .050" at the lifter.
Do it right.
Yoy must verrify true tdc with a piston stop first
Can be with heads on. Then do all event readings at the lifter.. Push rod tip is acceptable.
.050" at the valve is not .050" at the lifter.
Do it right.
Re: Cylinder pressure and advancing cam timing.
One valve end variable that F-BIRD may be thinking of is the fact that rocker ratios are often not as specified and variable, especially with actual springs vs. checking ones. A nominal 1.5:1 rocker might average anywhere from 1.42 to 1.58 and be as high as 1.75 or as low as 1.3 for the first 0.025"-0.050" of cam lift, thus the 0.050" lobe lift point might be anywhere from 0.065" to 0.085" or more at the valve. Then throw in the deflection loss due to say a 250# on the seat spring... 
Felix, qui potuit rerum cognscere causas.
Happy is he who can discover the cause of things.
Happy is he who can discover the cause of things.
Re: Cylinder pressure and advancing cam timing.
it is a fact that the engine airflow cares only about the valve motion so i dont see what good a theoretical seat value is in lieu of this fact. better to check the real "static" seat value IMO as that tells you what the entire valvetrain system is doing (for us mere mortals anyway)