Hi,
I just received my need roller rocker and now I need to check the new push rod length. It's a 85 350, I put a retrofit roller cam and lifter, I have <patriot Performance heads that require +.100'' on pushrod. I ordered an pushrod length checking tool with the rocker. I check this fast and I'm not sur if what I did is ok, I Installed the length tool and the rocker, then I tighten the rocker nut till the middle of roller was align with the middle of the valve. After this I took the reading on the pushrod, I got 7.295'' I don't know the right way to do this but Comp cam sells 7.300'' pushrod so maybe I'm ok?

 

Where did you set the lash and did you use a solid lifter?

 

I got retrofit hydraulic roller lifter, and how can I set the latch if I need the pushrod?

 

I use a solid roller lifter with zero lash if a hydraulic lifter is used or set proper lash if running a solid. It might not be necessary to do it my way but it was the way I was taught.

 

youll need a solid lifter to do this because a normal lifter needs oil pressure till its built up. if you try and use a pushrod into the lifter itll push down into a little bit. a solid lifter doesnt go down. and yeah you got the first part right with it being in the middle of the valve just need a solid lifter then measure

 

Ok, and there's no other way to measure the correct pushrod length? On Jegs website I see that retrofit roller lifter need 7.200'' pushrod, and I know that I need .100'' more for the head so I guess I can take 7.300?

 

You need a solid lifter or a hydraulic lifter modified into a solid lifter to check the pushrod length. It's also good to get lightweight checking springs to replace the valve springs you're using. The pushrod checker isn't designed to open a valve with a lot of spring pressure. Aftermarket springs are inexpensive but similar springs can be found at a hardware store.

With a checking spring holding the valve closed, use a Sharpie (magic marker) and blacken the tip of the valve. With the lifter on the base circle of the cam, adjust the rocker to zero lash (simulates a hydraulic lifter since there is no valve lash).

Wiggle the rocker back and forth to make a witness mark on the valve tip. Now rotate the engine by hand until the valve is at maximum lift. Wiggle the rocker back and forth across the tip of the valve to make a second witness mark. Rotate the engine so the lifter is back on the base circle of the cam and remove the rocker. The 2 witness marks should be on either side of center on the valve tip.

Keep adjusting the pushrod checker and redoing the procedure until you are as close as possible. Pushrod lengths are normally in .050 increments so if your perfect length is between .000 and .050", chose a length closest.

 

I don't have access to mechanical lifter atm, I can the local workshop and he said that I don't need mechanical lifter to check the pushrod length. He also said that these lifter move around .050''. I measured the play in my lifter and it give .160''. At zero on the cam, the the rocker is right in the middle at 7.260'' If I adjust the tool to give me the perfect center position and I remove .160'' to the reading it would be like an solid lifter?

 

The rocker has to be right in the center of the valve tip at half lift. The only way you're going to know exactly how long of a pushrod to use is to do the above procedure with a solid lifter.

 

ok,
How can I modify an hydraulic lifter into a solid one?

 

I agree with the above that using a solid lifter might be the best way to go, but oddly enough I had no issues using my hydraulic roller lifter to determine the length.

First thing I noticed about the checking spring is how light the tension was. The plunger didn't compress at all during the check, or if it did it wasn't enough to really matter...

I was able to determine through blueing checks that I could use a standard widely available length pushrod vice custom length ones. But I didn't so much verify that the rocker was right in the center of the valve tip at half lift - I just went through a entire rotation and made sure the pattern was fairly centered on the valve tip (maybe just a tad towards outboard)

Right or wrong it seemed to work fine...and I did a few different cylinders to verify everything stayed consistant. Ironically, I used to have issues with the tips of the pushrods breaking off before I went to a retro roller setup and verified the right length, but in my defense, someone else had set it up with the standard flat tappet lifters before I changed it over.

 

I COMPLETELY disagree with the advice about getting the rocker to land on the center of the valve stem; COmp's WRONG instructions on their web site notwithstanding.

What REALLY needs to be done, is to select the push rod length such that the rocker tip makes THE LEAST amount of travel across the vlave stem. Where it lands on the stem is ABSOLUTELY OF NO CONSEQUENCE.

The rocker tip travels in an arc, with its center at the pivot point of the rocker. (duh) Its natural motion is to start tipped back, with the tip over toward the intake side somewhere; then as it swings through its arc and depresses the valve, it slides across the stem toward the exhaust; when it is exactly perpendicular to the valve it reaches its far outer extreme; as it continues on toward full open, it comes back toward the intake.

WHen the travel is as short as possible across the valve stem, then the rocker's arc is exactly centered at half-lift of the valve. It DOES NOT MATTER where on the stem the pattern lands.

To properly check for push rod length, you MUST HAVE a solid (or at least, "solidified") lifter. If you don't, then the plunger in the lifter will depress when the valve spring puts pressure on it, altering the lifter height from what it will be when actually operating. It also helps to use very light "check" springs instead of the regular valve springs. You can use gear marking compound, white lithium grease, or even just black Sharpie on the tip of the valve, as something for the rocker to create its witness mark in.

Spin the motor through a couple of complete cycles on at least one intake and one exhaust on each side of th emotor, looking for the narrowest possible pattern, and ignoring the location of th epattern on the valve stem. Select the next shorter PR length increment than the one you measure, which puts the half of the rocker arc with the higher force on everything (the half towards full open) slightly straighter than the half with low force (the half towards full closed).

 

to shorten this up without all the controversy, here's an article that breaks down what I did and what I looked for:
http://www.circletrack.com/techartic...gth/index.html

Maybe I didn't describe the pattern I was looking for properly, so I'll quote the article:
Another Quote:

The above is why I didn't bother "solidifying" the lifter..... Sofa's method works well too I'm sure.

 

Does the Comp Cams 818 solid roller lifter suitable for this pushrod length checking in a factory roller SBC block?

As I saw on Summit there are a bunch of solid roller lifters and I am not sure which one should I use.