Measuring lifter pre-load

[tag]

I've got Edelbrock Performer RPM heads and the Lunati 60304 cam. I need to determine the pushrod length, so I was wondering if anyone else has this kit or if anyone has a link to some good directions as to how to measure lifter pre-load?

I have an adjustable pushrod, but I'm not really certain how to measure valve-train geometry.

 

[Meep-Meep]

Are you using adjustable rockers with 3/8" pushrods? If not you really should be. This is the one mod that I feel is a must with higher than normal spring pressures.

If you have the stamped steel rockers then you basically measure the total travel of the lifter from bottomed out position to the plunger fully extended and set it in the middle. That's the factory way. With adjustable rockers I make sure the ball end of the adjuster is as far into the rocker as possible while giving enough clearance for the push rod cup. Once the basic length is established I turn the adjuster in one full turn. On a 3/8-24 thread that's about .042" of preload - hardly in the middle. Total lifter plunger travel is about .200" I believe.

 

[tag]

I'm using the stamped steel, non-adjustable rockers.

 

[Cranky]

I don't remember what the Mopar Performance rockers arms are rated at but iirc, they are not up to snuff with that cam. If they are, then it's barely in the park and still wouldn't use them with the spring pressures that this cam should have. Why are you cheaping out on a nice set of heads like these? I mean these heads can be used to easily get into the 10's in the 1/4 mile.....

 

[tag]

You're kidding. These rocker arms aren't good enough? ****.

Well, one thing is, I am beginning to run out of money. But also, I've heard tons about how the steel rocker arms are actually quite reasonable for performance applications. My plan was to switch later on down the road. But since it mucks up my valve train geometry, I'm now seeing that's not a very good plan.

I can go with 1.5 roller rockers, I guess maybe I should just do it.

Even so, I still prefer the shaft mount non-adjustable type rockers. How about these? They seem to be spot-on rating wise and cost less than a grand.

http://www.summitracing.com/parts/CSP-S70015K/

The comp kit is rated for 1.54" springs, and mine are 1.55".

 

[bigmanjbmopar]

http://store.440source.com/Aluminum-Roller-Rockers_shafts-15-Ratio-New/productinfo/200-1045/

I used the adjustable rod. got 9.18 rods from 440 source then 1/4 turn past lash - done.

 

[Meep-Meep]

You don't have to have roller rockers. Just get the Crane or Isky iron adjustable ones.

http://www.summitracing.com/parts/CRN-64770L-1/