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help needed badly on pushrod length

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Old 10-16-2007, 03:53 PM
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Default help needed badly on pushrod length

ok i have a 98 ls1 ith 04 ls6 heads and cam, i upgraded to .7400 lentgh chromoly pushrods and installed comp r lifters. i have stock rocker arms, the car runs ok but i have alot of noise coming from the valve train should i upgrade the size a little bigger on the pushrods
Old 10-16-2007, 05:24 PM
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i get a PR length checker. thunder racing has them
Old 10-16-2007, 05:50 PM
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The Comp R lifters have a very tight tolerance on preload and it is also a very low preload (on the order of 0.004"). If you are running 7.400" pushrods you likely have way too much preload. The issue I think you will find is that with the Comp R's you may need custom pushrods or adjustable rockers.
Old 10-16-2007, 06:40 PM
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sorry i really guided u guys wrong on that one i have oem style lifters i just went to the website on comp cam and i got the oe style from comp for some reason i was thinking i had the type r but im incorrect on that sorry guys and i appreciate all the advice i can get
Old 10-16-2007, 07:34 PM
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Oh, OK. Best bet is to measure but an aggressive cam profile will make more noise. Some have said aftermarket rockers will quiet it down some but start with the basics and measure first. Also, did you check the wipe pattern? Its an important step in the process of ensuring a correct valve train geometry.
Old 10-16-2007, 08:54 PM
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i went and measured the pushrod with a checker and it seems with the factory 7.400 i have side to side movement like there is not any preload but when i use the checker and make it 7.450 its nice and snug and has a lil preload
Old 10-16-2007, 09:14 PM
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I have 7.450's with my cam in sig, per Patrick's suggestions. The valvetrain noise is no worse than stock IMO.
Old 10-16-2007, 09:39 PM
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im lost totally on this, but i think it makes sence that the shorter ones will make noise




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