<div class="bbWrapper"><blockquote data-attributes="member: 53984" data-quote="MacksRam" data-source="post: 370697"
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data-content-selector="#post-370697">MacksRam said:</a>
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mbarber84,<br />
Good info--thanks.<br />
This sentence caught my attention: "<i>They did, however, change the manufacturer for the roller that attaches to the lifter body."</i><br />
Do you have any more details on this?
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</blockquote>Both the lifter bodies and the rollers that attach to them can cause premature lifter failure. <br />
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The chief mode of failure, when referring to the lifter body as the culprit, is the roller axle bore. If that bore is drilled / machined on any angle other than parallel to the cam shaft, it causes the roller to sit at an odd angle to the cam lobe. When this occurs inside the engine, it creates increased stresses on one side of the roller, and a twisting force as the roller runs up the cam lobe. What you end up with is premature wear on one side of the roller, eventually leading to surface spalling. It can also cause the lifter to twist axially in its bore, further increasing the failure rate. As the wear continues, it will eventually start to cause the roller to seize or develop a flat spot, at which point the failure accelerates rapidly. <br />
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The chief mode of failure, when referring to the roller, is its profile across the width of it. Some of the rollers are manufactured poorly, where one side of it has a large diameter (or smaller diameter) than the other. This created a “tapered” roller, which increases stresses on one side more than the other. From there, the failure is very similar in nature to what i described above for the lifter body related failure. <br />
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In either case you end up with stresses and surface wear that is not uniform, but rather concentrated on one side or the other.</div>