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Valve Lash question .002 cold????

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Old 01-06-2009, 03:54 PM
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Default Valve Lash question .002 cold????

Awaiting my parts but I was told the cold lash would be .002 and hot would be.010 Seems rather tight to me and just wanted to do a little investigating. I do not know the brand of the cam until I get my parts. I had planned on calling the cam company to make sure this was correct. This is a solid roller cam with aluminum block. Heard that expansion was more with aluminum and being this tight would be better for some street use?? Thanks for the help guys.
Old 01-06-2009, 04:26 PM
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Update: Talked to Cam Motion as I am 99% sure it is there cam and they said on the LS stuff the tighter the better. They said it has better carateristics than a typical solid roller setup, less noise and doesn't beat up the valve train as bad. Still would like to know what you guys have experienced with these setups. Thanks again.
Old 01-06-2009, 07:01 PM
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The block expands a good amount once warm and opens up the lash. If you set it to .002 then warm up the engine and re-check it's gonna be .010-.015.
Old 01-06-2009, 07:06 PM
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I understand that but other setups usually are .006-.008 cold. Maybe that is due to race only setups??
Old 01-06-2009, 07:21 PM
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It's determined by whatever the cam manufacturer recommends. Which I'm sure is based off of lobe design and ramp rates for what works best with what cam. I've only had experience with Cam Motion solid rollers and .002 is what they speced out.
Old 01-06-2009, 07:36 PM
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Have you had luck doing the .002 cold? Or have you seen more/less out of your setups? Cam Motion said to adjust cold at .002 and get hot and check and as long as it is no more than .012 hot you are good. If it is more than .012 he said to adjust them hot until you are within the specs and let cool completely to see what you cold spec would be. This way you can set cold in the future and you know they will open to your .012 hot lash. It was really good info from Cam Motion and made alot of sense.
Old 01-06-2009, 08:01 PM
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The .002 worked well. The car belonged to my cousin and it was a 98 with valve cover spacers and coils in the stock location. It was a real chore to pull the valve cover off quickly after warming the engine, so I only did that once and only on one side. The hot lash was .010-.012 on every rocker on that side.

I can tell you that when the lash needed to be adjusted that the cold lash was generally .004-.006. After setting the lash to .002 the valvetrain is very quiet, but at .004 and higher it would tap fairly loud.
Old 01-06-2009, 08:22 PM
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Thanks alot for all the help and the info, it will help me out in the next couple of weeks as I get this thing finished up.
Old 01-06-2009, 08:50 PM
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With an iron block and aluminum heads(mostly BBC's and SBC's), we set the cold lash .003" tight with steel valves and .010" tight with titanium valves. On the dyno you can warm the engines up and re-check lash and they will be within .002" of your desired number. The aluminum block is the reason for tightening up the lash a few more thousands on the LS engines though.



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