rodb and mark

Have you got the essays done yet. I asked mark to explain how lifter diameter effecfs valve opening rate or speed. I asked rod b to write why he thinks a crank fillet with a fixed radi is stronger than one with a non circular contour. Which a fixed radii isn't stronger. It was all ap attempt to get the peanut gallery add something knowledgeable to the forum. Failure again.

thanks brian your on the right track. The velocity that can be given to a lifter is dependant on the lifters diameter. A flat tappet lifter mushroom like a 226 can initailly accelerate faster than a .700 roller wheel  when under 280 degrees of duration . With higher quality oils and lifter materials coatings etc and the fact that a lifter isnt really flat, small roller wheels really havent got a advantage in the friction department anymore. Rollers do have a advantage when dealing with heavy spring rates to some point but the small trunions can still break when trying to  get  the flank velocity up to that of a mushroom flat lifter. Circle track engines have been using at a minimum the ford lifter and when they can the mopar .904 lifter for years now unless rules dont let them.  If someone can rev a 226 to the point of valve floating a 1.509 diameter spring. Then they need a large roller trunion .  its all in the cams flank. lol

Edited by mlpankey - 03 Feb 2012 at 6:36pm