Whats the difference with more or less lifter preload?
Whats the difference with more or less lifter preload? OK im running morrel lifters. Thinking specs are .030-.050 preload ?
Lets say engine is set at .025-.030 will it be pumping less oil to top of engine?
Whats the affect of have more preload or less preload on a lifter?
Lets say engine is set at .025-.030 will it be pumping less oil to top of engine?
Whats the affect of have more preload or less preload on a lifter?
I think preload is less about oil pumping and more about keeping parts of the valvetrain in contact with each other. Too little preload and your pushrods will start bouncing off of your lifters, resulting in valve float or perhaps something worse.
Too much preload will not let the lifter fully pump up, and may damage the lifter, cam, or pushrods.
If I'm full of ****, someone please jump in here and correct me.
Too much preload will not let the lifter fully pump up, and may damage the lifter, cam, or pushrods.
If I'm full of ****, someone please jump in here and correct me.
Preload is basically a happy medium.
You want to keep a constant pressure on the lifter, without bottoming it out. This takes up any lash in the valvetrain.
As long as the preload is within spec, it shouldn't affect oil flow to the top end of the engine.
You want to keep a constant pressure on the lifter, without bottoming it out. This takes up any lash in the valvetrain.
As long as the preload is within spec, it shouldn't affect oil flow to the top end of the engine.
TECH Apprentice
Joined: Dec 2008
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From: Westbank of N.O.
Every engine builder has his own preference, but in my experience w/ hyd. rollers, slightly less pre-load = more usable rpm and louder valvetrain. More pre-load = less off-idle torque and 100 or more less rpm on the top-end. This would be agressive ramp-rate cams in the 230*-up area, and if u have a lot of overlap, looser helps the idle. You can definetly hear mine if that tells you anything about my thoughts.
Every engine builder has his own preference, but in my experience w/ hyd. rollers, slightly less pre-load = more usable rpm and louder valvetrain. More pre-load = less off-idle torque and 100 or more less rpm on the top-end. This would be agressive ramp-rate cams in the 230*-up area, and if u have a lot of overlap, looser helps the idle. You can definetly hear mine if that tells you anything about my thoughts.
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I think preload is less about oil pumping and more about keeping parts of the valvetrain in contact with each other. Too little preload and your pushrods will start bouncing off of your lifters, resulting in valve float or perhaps something worse.
Too much preload will not let the lifter fully pump up, and may damage the lifter, cam, or pushrods.
If I'm full of ****, someone please jump in here and correct me.
Too much preload will not let the lifter fully pump up, and may damage the lifter, cam, or pushrods.
If I'm full of ****, someone please jump in here and correct me.
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Launching!
Joined: Apr 2005
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From: CAIRNS QLD AUST
what do think about this
http://speedtalk.com/forum/viewtopic.php?t=1562
http://www.cranecams.com.au/pdfs/pp1110c.pdf
http://speedtalk.com/forum/viewtopic.php?t=1562
http://www.cranecams.com.au/pdfs/pp1110c.pdf
Last edited by red 454; Aug 15, 2011 at 02:19 AM.
