Quote:
Originally Posted by Greg Reimer 7376
Well, here I am at 6:07 AM on a Monday reading this. Here's two more cents. Since most of these stocker cams are ground with more precision and consistancy as to lobe lift and profile, which can be verified by checking all 16 lobes with the cam in the block, then the places correction is necessary would be in the rest of the valvetrain. If all 16 lifters check,then the pushrods, rocker arms, and the valve stem lengths have to be considered. The post regarding minimizing the sweep of the tip of the rocker arm across the tip of the stem revealed the secret to minimizing valve train friction, that sounds like the optimum goal. Variations in rocker arm ratio and valve seat depth and variations in stem length are the only variables left to play with. The actual ratio of rocker arms vs. effective ratio is one more thing to concern yourself with. Seems like these two threads have revealed more areas of thought to be considered than anything else I've seen in a long time.Yes, push rod length is more critical than most persons have probably thought.
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Greg
Several years ago, I made myself a rocker ratio checker. It is simple. Take a flat piece of metal and install a stud. Really needs to be what ever stud diameter your rocker system. Since I was using a small block chevy, I used a 5/16 steel ball out of a roller bearing. I then placed this on top of a gage block. It seemed easy to put 1 inch lift on small side of rocker ratio was easiest to use. I then put a dial indicator on the large ratio side. You can then measure the correct ratio of the larger side. I then went thru every stamped rocker arm I could find. I then put 8 together for the intake and 8 more for exhaust. All as close to each other as I could get. While doing this, for my stock rockers, I decided to check some roller rockers that I had (used-couldnt afford new ones). Man was I ever surprised at what I found. You have to remember this was several years ago and I found out later that some companies was still repeating the wrong way to build a rocker arm. I had no idea what was wrong but I knew it was wrong or the rockers did not make 1.5 (SBC). I was at one of the first PRI shows in Nashville, Tenn and I went to a presentation by Smokey Yunick. I waited until after his presentation and asked him. His comment was " Damn son, dont you know that cause it is new does not mean it is right" He then splained the world too me in a language that embarrassed me then. I came back and got a set of rockers (used)like he told me to get and they checked all the way thru a rotation. Apparently, people like he and Bill Jenkins new this but I had no clue.
reed