Ive always heard of 2 ways to get to the base circle of the cam and have always wondered if these 2 ways are equal or if one is better. In my mind they are the same but wanted opinions.

Method 1 is simply bring lets say cylinder 1 to tdc on compression where both valves are closed. This should accomplish base circle and you can go ahead with measuring for pushrod length and lifter preload.

Method 2 is watching for the exhaust valve to open then measure for intake. Then waiting for intake to start closing then about half way into intake closing do the exhaust.

What you all think?

Alex

 

Method 2 is how I always adjusted my solid lifters when "bumping" the engine over with the starter. When the engine is on the stand with a degreed balancer and you are turning the engine with a wrench, method 1 is quicker since you can check both valves in one position. Both methods have the lifter(s) on the base circle of the lobe and are equally accurate for measuring.

 

Im going to try both since its on a stand and easy. Ill see if they both have the same measurement.

 

I do it a bit different than most. Since my motor is always in the car when i am measuring for pushrod length, i put my 2 checkers in, hold my finger on the tops as i turn the motor over with a big ratchet, and watch and feel that the pushrod isnt moving for a couple partial turns of the ratchet, then put my rockers on and adjust my checker to zero lash, pull it out and measure with a large caliper, then add my preload. I measure all pushrods at least 3 times to verify i am correct. Works every time.

 

I just use TDC. Cylinder #1 lifters are both on the base circle at this position.

 

i just did both and ended up with same measurements. Do what makes you feel confident in your readings.