Pushrod length tool came with NO instructions!

[Kern Dog]

What is with these parts houses that sell stuff with NO INSTRUCTIONS INCLUDED ???
I'm installing some aftermarket roller rocker arms and need to get a correct length pushrod. The PR length tool I got from Mancini has no numbers on it. It has some dashed lines. It has a threaded in end that gets longer as you unwind it. It has a rounded/ball end for the lifter and a cup end for the rocker arm adjuster. GREAT...It ranges from 8.8 to 9.8 inches. I'd hoped that for each turn of the tool it would equal a .10 of an inch, but I was able to spin it 22 times before it came apart.
Here is where I am confused. After getting the rocker arms & shafts bolted down and the PR tool extended to allow zero lash, I'll remove the tool.
If I simply measured it end to end, how could that be accurate? Do ALL pushrod manufacturers use the same specs for the cup end? See, the point of contact is from the tip of the rocker arm adjusting screw to the concave recess in the lifter plunger. If Acme makes the cup end different than Crane, the measurement will be different.
Any ideas?

 

[BigBlockMopar]

Any difference in ball or cup-size (...) is easily taken up by the adjustability of the rocker I would think.

 

[whodacudaman]

gotta be the same length as an average chiquita banana.....lol. why wouldnt it come with instructions! prob made on the great wall and they blew over as they were packaging.

 

[ken5124]

Got to Hughes engines website.. They have instructions for their adjustable pushrod checking tool that should help you out.

 

[FJ5]

Here is a link to hughes [ame]http://www.hughesengines.com/Upload/productInstructions/LengthCheckerMar2013.pdf[/ame]

 

[flyfish]

When I did mine, I just took my measurements (with 1-2 threads exposed), locked down lock nut on the tool to make sure it didn't move in transit, put duct tape on the lock nut for added insurance, and mailed the tool to Smith Brothers with a note that said "I need 16 of these" :-D....well, more or less. They have a spec sheet where you specify wall thickness and such too.

 

[jos51700]

You spun it 22 times and it came apart, but that's not accurate, you've gotta have some threads engaged to use the thing.

Can you determine the thread pitch? (That's the number of threads in an inch)
If so, run it out until it just seats in the rocker and lifter, and from the thread pitch, you can calculate how much the length increases with each turn, and that will tell you how far you're pre-loading the lifter.

example: 6-32 threads have 32 threads per inch.
1 divided by 32 equals....0.03125
so each single turn of the thread adds or subtracts (depending on the direction being turned) 0.03125 inches.

Those Hughes instructions on cleaning geometry are great! I'm saving that!