Just as everyone does, I have a few unique ways of doing things when I assemble an engine, so I thought I would share some of these tried & true pointers to my Nasty Z buddies.. This is a proven time saver for achieving correct rocker geometry and it works excellent. I do the first step before I assemble the heads and install them on the motor. What I am looking to do is get my contact point on the valve tip to be in the same location at max lift as it is when the valve is closed. Think of a rocker arm being able to rotate in a full circle. So the lift at the valve that is created by the rocker movement is simply a pie shaped portion of the full circle. I am looking to make the center of the rocker pivot point & center of the roller wheel to be 90 degrees to the valve stem angle at mid lift. By doing this I will split the arc of the rocker movement in half, 1/2 going from valve closed to mid lift, and the other half from mid lift to max lift. See my bad drawings for an illistration.

http://i44.photobucket.com/albums/f21/doechsle/badpix.jpg

http://i44.photobucket.com/albums/f21/doechsle/lastscan.jpg

Now that you see what im looking to achieve, i'll show you a fast surefire way to go about it. With the head standing upright on its end I install a valve seal to act as a lift stop for my valve.

http://i44.photobucket.com/albums/f21/doechsle/000_0233.jpg

I use a pair of dial calipers to position the valve stop at the lift measurement.

http://i44.photobucket.com/albums/f21/doechsle/000_0234.jpg

next with the valve closed, I will color the tip of the valve with a majic marker and put my rocker arm on the stud. I will just eyeball the contact point of the roller wheel on the valve tip by pulling the rocker up against the adjustment nut. As im pulling the rocker arm up against the adjustment nut (acting as pressure that a pushrod would apply to the rocker) I use my thumb to spin the roller tip against the valve tip to leave me a mark in the ink from the majic marker. I will rotate the valve 1/4 of a turn clockwise and push the valve down till I get to my lift stop. The I will once again pull the rocker up against the adjustment nut and spin the roller wheel to leave a mark for my max lift position. Now I have 2 marks on my valve tip , I take my dial caliper and measure from the edge of the valve tip to the max lift line, then I measure the valve closed line. When you get the same measurement from the edge of the valve to the line on both valve closed marks and max lift marks,then thats where the rocker needs to be. Sorry bad picture but you can see the 2 lines.
http://i44.photobucket.com/albums/f21/doechsle/000_0235.jpg

Now that I have the rocker nut where it needs to be,I put the head on the block with the valve closed. (Make sure you have your head gasket in between them ) I put my pushrod legnth tool in the lifter and start expanding it out till it contacts the rocker arm.That's my length im looking for. I put a small piece of tape on the pushrod tool to keep it from changing as I take it off the motor. Measure the length of the checker and thats the length of the pushrod you will need. If you dont have a pushrod tool, take a stock pushrod and cut it in half, the i.d. of the pushrod is just right for threading a 1/4 x20 tap into it . Thread both halves and use a short piece of 1/4x20 threaded rod to put it back together, now you have a push rod tool. One more tip here, my dial calipers only measure up to 6", and pushrods will be longer than that, so I lay my pushrod on a piece of paper and mark where the ends are. Now I use my 6" calipers. I measure off 6 " then from my 6" mark I measure the rest and get my overall legnth. Give it a try on your next build.:)

doechsle, This looks like a neat way of doing this on the bench before the head are on the engine.

I have been trying to figure out a way to check mine without disassembly of the heads, at least one pair of valves on each head. I was hoping to use a pair of solid lifters. The best I can tell is that I will have to use the checking springs with my hydraulic lifters to find my correct pushrod length.

I'm going to give this method a try. Then I will take some pics and see what you guys think. Any recommendations on a valve spring compressor? Thanks, Russ

It is really a net way of doing it, and believe me it is a time saver. It may not make alot of sense till you do it and see how its kinda backwards but very accurate. As far as a compressor, I like the one that works the best. No, really there are different styles that have strong points in certain conditions. Some clamp to the spring and compress the retainer, some use the stud and some only work with the head off. Give it a try.

Exellent post!

For BB 3/8" push rods, the hollow center is too big to tap for 1/4" but if you put a 2" peice of 1/4" rod in you can use 1/4" washers to shim the pushrod longer.

Rustover:
Using hyd lifters, you can just compress a lifter. I put a dial indicator on the p/rod end of the rocker arm and tighten the nut down and measure how much the plunger travels. Keep the lifter compressed while figuring out p/rod length, and just subtract the travel from the length of the p/rod you come up with.

My hyd rollers compressed .110"
Figured my pushrods to be 8.86" exaust minus .110" lifter compression = 8.75" long

Will you always end up needing a pushrod lenght that is available??

Will you always end up needing a pushrod lenght that is available??

Hulk, I just noticed no one had responded to your question. Don't want to horn in on doechele's post here, but just wanted to mention that pushrods are available (and typically in stock) in 0.050" increments. So max error would be 0.025" from 'exactly' what you need. But in the real world,, deflection throughout the valve train is not going to make that 0.025" error a moot point.

Thanks Marv, I didnt realize there were so many lenghts available..
Hulk

WOW!!!!!!
Hulk...

can you check the pattern with a stamped steel rocker?

yes but it will not be as precise, the stamped rockers are not very consistant. They will always have a wide pattern also.

Good post!

I haven't made it yet but I am wanting to make a pushrod length gauge. I'm thinking of using a piece of angle iron (small) to lay the pushrod in with an adjustable collar welded to the end of it and a lifter cup welded at the other end. I can clamp my dial indicator in the collar and zero off of a standard length pushrod, then either measure my length checker or measure any pushrods I have.

I just installed one of my vortec heads on the short block and installed the cam and #4 cyl intake valve with a low tension test spring..
Looks like the stock pushrod is very close to the right lenght for me..A touch shorter would be ideal but I think itll be fine..
Excellent info here..
Is there a way to check if your pushrods are hardened??File??
Hulk...
Looks like the stock valve covers will also work with slight mods with standard roller rockers..

I just installed one of my vortec heads on the short block and installed the cam and #4 cyl intake valve with a low tension test spring..
Looks like the stock pushrod is very close to the right lenght for me

Would this (as Hulk mentions) be an accurate way to check your current pushrod length before I go out and buy an adjustable PR to determine correct length?

I just swapped from a hydraulic cam with stock SBC length pushrods, and old AFR heads to a solid lifter cam and the new AFR eliminators. I would mock the motor up with checking springs and my current pushrods, and from there follow doechsle with his way...only with the head on the block.

Hey Greezer. Have you used these guys before? Got prices on a set of custom length pushrods. Suprised how inexpensive they were. Need to know how they are before I order. Thanks
Erick

this website is the freakin greatest

I re-read the procedure and see how it works
Thanks