OKay I need some advice. I was checking my valvetrain geometry on the new motor. Without a head gasket, the roller tip rested on the intake side of the valve stem, on the inner third of the stem. As I rotate the engine over, the roller tip rolls to the middle of the valve stem and stays there until the valve begins to close and then it rests of the inner third of the valve stem again. Is this okay?

 

With the gasket in there, it will put the geometry out, that gasket will pull the roller closer to the intake side of the valve tip, you need to set the gasket in there and see what happens...

 

No that is not correct. Use these 2 pages as your measurement guide.
http://www.compcams.com/Technical/Cu...ML/306-307.asp

 

Yeah - that article should work out for you...basically you want to have the movement of the roller over the valve tip to have it's centerpoint in the middle of the tip...at the base circle and at max lift the distance from the very center should be the same. This keeps the valve from being excessively side-loaded so your guides don't wear out faster.

 

If you are referring to.... #2 'Determine correct valve train geometry', I'll disagree. While the principle is OK, they sure lack a complete description of what is desireable. According to the CC recommendation, the person checking could easily end up with a pattern 1/8" wide, or WIDER. While it is great that roller rockers can alleviate side 'scrub' noticeably, doesn't imply all caution should be thrown to the wind, in regards to side motion. The goal is to attempt to achieve the most downward motion, and the least sideways motion.

To schools of thot, regarding what I consider correct setup.
One goal is to achieve the least amount of side motion or 'sweep' of the RA. This however, may put the sweep slightly off center of the valve stem.
The other, is to achieve a centered pattern on the stem. This however, may very well lead to a little wider sweep pattern. The least amount of sweep, slightly off center, is considered by many, to be the most desireable.

To mock up the setup without a complete assembly, is little better than using the incorrect length of valve in the mockup.

 

Well genltemen this is what I found out. Got the heads on and was checking my length again. Unfortunately there was no oil in the lifter but the pattern looked good, much like what CC reccommends but with one difference. As the rocker arm reached max lift it stayed in the center of the valve stem instead of roller over to the outside portion of the stem. I figured that when the lifters are pumped up it will push it over the where it should be. I hope I explained that clearly enough. My next question is it doesnt matter if the lifter is pumped up or not with the cam on base circle, the rocker arm is going to set where it is right?

 

Answer that question with this one. Is the RA going to set at the same angle to the valve axis? The relationship of RA to valve at mid lift is a factor, and important here.

 

Im not sure i understand

 

As the rocker's movement is in an arc, in lieu of up and down, the greatest ratio generated, I.E. most lift, is at a point where the RA is perpendicular to the valve stem. Thus the reasoning of noting how perpendicular the arm is to stem at mid lift. The more time the rocker spends at or near a perpendicular relationship, the closer to the designated ratio multiplication you will achieve.

 

This seems a little over my head ... so what I should look for is a pushrod that on base circle will put the RA prependicular to the valve stem??