I'm looking for confirmation of my pushrod length - I know, it sounds like a personal problem-LOL. But seriously, I'm working on the valvetrane (sp) of my stroker engine and would like some input from guys with more experience. I'm running 1.6 roller rockers from Howards Cams. Here is a pic of the contact pattern on the valve stem using an 8" pushrod. I think it could be a little more to the center, but my lifters are collapsing for the first 1/8" of travel before lifting the valve off the seat. I'm thinking that once there is oil in the lifters the rocker travel will be a bit longer and more towards the center of the valve stem. One more question, what is the preload on the lifters when you tighten the polylocks? Is .020" enough or should it be more? Thanks!



I just put a little Sharpie pen ink on the tip. Does this pattern look good?





My polylocks are short and some of the flats from the hex nut are down in the rocker body. Is this a problem?

 

Yes that's a major problem. You want nothing touching the rocker anywhere.
You need guide plates with that setup which will raise the stud up some which might help. You'll have to check it.
Take the lifter and submerge it in oil and pump the plunger until all the air is out of it that will help you get a better reading. Also it's much easier to use checking springs then the actually spring for the job. Much less pressure to deal with. You'll drive yourself crazy doing it that way.
Most lifters are .020 - .060 preload. Most studs are 16 threads per inch so each turn is a 1/16 of an inch which is just over .060 inch. That makes half to one turn of preload.
I really think you are going to need taller poly locks

 

Also, having the pattern outboard like yours is shows that you have the pushrod too long. Ideally you want a narrow pattern centered over the tip. Easier said than done. Take those heavy springs off for testing purposes and make it easier on yourself.
At mid lift you want the roller in the center of the pattern. Zero lift it will be on the inboard side and max lift will be on the outboard side.

 

I saw some springs at tractor supply that would probably work good for a checker spring, or you could order some from Jegs, Summit, Howards etc. You dont want the lifter compressing, maybe use a drill to prime the engine/ pump up the lifter would help with that.

 

Trip: With the current pattern (using 8" pushrod) the rocker seems to start on the outboard side of the valve stem and move inward with cam lift. I don't have the original factory pushrods (I tossed 'em, should've keep one for comparison). What's a typical pushrod length (if there is such a thing) with adjustable rockers? Also, I do have 3/8" guide plates; I had to remove this one for checking because it was interfering with the adjustable pushrod. Thanks for your help with this.

Rodney

 

Can you place the adjustable part down toward the lifter? Not sure if it will fit through the push rod hole or not. If need be you could assemble and disassemble it in the valley and just count the turns it takes when you do that. You'll need the guide plates in there to be accurate.
A narrow swept line is more important than the placement on the tip. Of course ideally you'll want it centered but you are not far off and adding the guide plate might be just enough to get you where you need to be.
There's no typical push rod length because there are too many variables now. You're on the right path but you need to really get a light spring under there and not beat yourself up.