Bushed Lifter Bores
Bushed Lifter Bores
Tom
<small>[ March 10, 2003, 09:54 PM: Message edited by: FSTR-THANU ]</small>
Tom
Gets back to the post JoeK made a couple days ago about the solid roller oil pressure problem, with the lift & base circle of the cam causing the lifter to slide past the oil hole on the lifter bore, thereby causing the 'leak'.
Approx. what lift cam are you running? I'd assume it's larger than .65", no need to be real specific. Thunder's had no trouble with a .60" cam, but I'm just wondering ( <img border="0" alt="[evil]" title="" src="graemlins/gr_devil.gif" /> ) where a cam with something like .64" is going to fall for this low oil pressure phenomenon.
-Andrew
As for the lift of the cam....it does not have anything to do with the reason that some have good pressure and other don't. Each lifter, generally, has what is called a wedding band around it. Basically a indent where the lifter gets it oil while on the base circle. On a solid roller the oil is shot straight threw the lifter and up the pushrod to the rocker. Pretty much free flowing design. With that being said you need to restrict the oil from putting that much volume threw the pushrod. On a hyd. roller the lifter does this for you by the way they work. Also with out the bushings installed, the oil galley hole is very large, say the size of your thumb. When we put the bushings in we restrict these oil galley holes to .040" to .060". By doing this it limits the amount of oil the lifter can see. Thus reducing the amount of engine oil flow, which in turn keeps the oil pressure at a good level. You can do this also by keeping the lifter bore to lifter clearance tight, .001" or less. There are also a few other ways that you could help this "bleeding" problem, but the bushings are a sure bet that will work all of the time. I hope this makes sense to you, I am having trouble putting it into words I think. Brain freeze!!!
Thanks,
Chris Gelineau
Diamond Pistons
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For example, the Crane 10510-16 - intended as a SR 'drop in' replacement for an OE Hydraulic Roller lifter, versus a standard CompCams SR lifter? Crane's web site states boldly that they do "NOT recommend the use of oil restrictors" - which is what this bushing is, is it not? I'm just very curious, that's all. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Thanks,
Andrew
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