IHADAV8.com - Turbo Buick Tech, and Nonsense
Tech Area => General Buick Tech => Topic started by: chrisgarrett on May 29 2011, 12:32:08 AM
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I have a roller cam with adjustable rockers. I want to quiet things down a bit. What should I set the preload to?
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are these the lifters that are supposed to be set at .003" or the other variety that take a conventional preload?
I doubt that adjustment will do much, if anything, tho
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These are T&D rockers. I guess what I'm asking is, willl more preload quiet them down? Right now they are set at .025. Do you think .030 or .032 will quiet them or make them worse.
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It is the lifter design that determines preload so you must know how much preload the lifter requires.
Comp has one lifter that is designed to run at basically zero preload-.003", I believe.
The other runs at a more conventional preload...some thing like .020"-,040".
Knowing which lifter you have is the starting point.
In the second case, it should not be sensitive to the the setting, particularly at your current preloads.
With adjustable rockers, it is easy if you know the thread count of the ajuster. For instance, 20 tpi means that one complete turn is .050".
So you know that a half turn to three quarter turn after zero preload is a good range.
If they are 25 tpi, then one complete turn is .040"
Roller cams are like conventional flat tappets in that the lobe ramp design makes some cams a bit more tickety than others.
I believe that I just said I doubt it will make any difference if you have the second type of lifter.
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Thanks Steve.
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Also adj. rockers are for fine tuning. I would not go more than .020 either way. If you need to get longer or shorter pushrods.....