Farm Equipment - rodb and mark

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rodb and mark

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=44926
Printed Date: 11 Sep 2025 at 7:25pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: rodb and mark

Posted By: mlpankey
Subject: rodb and mark
Date Posted: 03 Feb 2012 at 10:27am

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.

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people if they don't already know it you can't tell them. quote yogi berra

Replies:

Posted By: Brian Jasper co. Ia
Date Posted: 03 Feb 2012 at 5:21pm

I saw a discussion on one of the FE Ford boards talking about lifter diameter. Diameter didn't have anything to do with valve opening speed, but a larger lifter was supposed to be able to stand a steeper lobe which would open the valve faster. If anybody in the Ford world is going to know the answer for sure, it would be either Barry Rabotnik or Jay Brown...

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"Any man who thinks he can be happy and prosperous by letting the government take care of him better take a closer look at the American Indian." Henry Ford

Posted By: mlpankey
Date Posted: 03 Feb 2012 at 6:32pm

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

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people if they don't already know it you can't tell them. quote yogi berra

Posted By: Brian Jasper co. Ia
Date Posted: 03 Feb 2012 at 7:33pm

Materials and technology improvements were some of the discussion too. Hardening the parts to the point of being able to cut glass. I was thinking I wanted to go roller cam without question due to the reduction of ZDDP in oils today, but if the metal tech has improved that much, I might use a Comp Cams XE282 in the 445 project.

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"Any man who thinks he can be happy and prosperous by letting the government take care of him better take a closer look at the American Indian." Henry Ford