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Push rod length mystery...

Posted: November 24th, 2012, 2:54 pm
by Alexia
I started with 9.547" push rods that I calculated should give me roughly 0.037" of lifter preload. Somehow with those I ended up at 0.077". Whatever, I can order different push rods for this simple mistake. So I ordered 9.5" push rods to reduce the preload by 0.047" down to 0.030". Now I am measuring 0.015" lifter preload. I have no idea what is going on.

Additional preload measurements:
Valve #1: 0.015"
Valve #2: 0.037"
Valve #3: 0.000"
Valve #4: 0.001"

Maybe it is possible to see what I am going crazy now.

Re: Push rod length mystery...

Posted: November 24th, 2012, 5:17 pm
by rammit11
are you sure you are on the base of the cam lobes? is this a hydraulic lifter cam? I know that if you go to cranes sight they explain how to check the preload on the hydraulic lifters .

Re: Push rod length mystery...

Posted: November 24th, 2012, 5:32 pm
by SilverXJ
And what exactly is your method of checking preload and push rod length measuring? What was done to the head? Where are you getting the pushrods from? What cam?

Re: Push rod length mystery...

Posted: November 24th, 2012, 5:46 pm
by dtholt
I USED OLDSMOBILE 455 PUSHRODS ON MY STROKER

Re: Push rod length mystery...

Posted: November 24th, 2012, 8:14 pm
by Alexia
I figured out the mystery. Apparently top dead center with the harmonic balancer's notch lined up on the zero is not top dead center. The timing set is installed correctly and is brand new.(Nice and taunt~) It is just that either the timing cover or harmonic balancer is off for where zero is located. After some fiddling I have every valve 0.020" to 0.045" of preload. So I just have some 9.5" push rods around for some purpose in the future!