How do I measure push rod length

[Andres2882]

OK, I have the tool from summit. Now all i need to know is how to use it. No joke, if anyone can spell out in plain english all the details, that'd be a life saver.

 

[87'GTstang]

You will need something else, a dial caliper to go along with it. Try adjusting it to the stock lenght, 6.272?? I believe. Then install a solid lifter in the bore you are using (also gutting a cheap stock/junkyard one and welding the plunger cup will work). Install the adjustable pushrod, color the tip of the valve with a marker that will rub off, install the rocker arm, tighten to specs with that valve closed, rotate the engine around and watch the full cycle of that valve from open to close again. Make sure the valve is closed again, remove the rocker arm, then inspect the head of the valve. You want ideally the most center portion of the valve stem surface uncolored. If you are too far towards the exhaust side, try a longer length pushrod and if too far towards the intake side, use a shorter pushrod length. Repeat the above process. When you find a length that works, take the pushrod out and measure again with your dial caliper, order the closest-sized set of pushrods to what works best for you.

Any more questions?

 

[Andres2882]

That about sums it up. Thanks.

 

[Vipersix]

Seems to be pretty sound advice but I want to be sure you understand the theory behind the valvetrain geometry. While the marker idea is doable and accurate enough for most applications, the best technique is to watch the rocker carefully as you rotate the engine. The roller portion of the rocker should travel from the front (intake) of the pushrod, to the center, over to the back (exhaust), and back to the front again. Before you attempt to check the length, be sure the valves are fully closed. Rotate the engine until the intake valve just begins to open and then rotate backwards slightly. Then install the pushrod checker and do your magic.

Good luck.

 

[Modular2v]

Seems to be pretty sound advice but I want to be sure you understand the theory behind the valvetrain geometry. While the marker idea is doable and accurate enough for most applications, the best technique is to watch the rocker carefully as you rotate the engine. The roller portion of the rocker should travel from the front (intake) of the pushrod, to the center, over to the back (exhaust), and back to the front again. Before you attempt to check the length, be sure the valves are fully closed. Rotate the engine until the intake valve just begins to open and then rotate backwards slightly. Then install the pushrod checker and do your magic.

Good luck.

why does our magic always involve spending money?

 

[Vipersix]

There's a conspiracy out there to catch us all in a big trap known as the Quest for More Power.

 

[Andres2882]

Thanks again!