Author
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Topic: Valve lash?
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Dave_C Gearhead Posts: 744 From: Gadsden, Al Registered: Aug 99
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posted 03-14-2001 08:52 PM
How much can you change the valve lash from the cam company specs and still be safe.Time for my regular maint and it seems that my lash is a bit wide. I have a custom ground Comp Cams solid roller. Their specs are hot intake .026 and exhaust .028. The chance is has moved since the last time is practically zero since I installed the stud girdles, but I'm checking just to be safe. Thought about going a little tighter and try to boost the bottom end power a little. Also, how mich diff should there be between hot and cold lash. The engine is a tight fit to start with, but add tall valve covers, stud girdles and export brace and it has had time to get cooled off before I can re-set the lash. Cam specs if it matters: .624/.630, 262/272 dur @ .050 lift, 295/305 adv dur, 104 lca, installed straight up. Thanks, David Cole
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Moneymaker Administrator Posts: 19704 From: Lyons, IL, USA Registered: May 99
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posted 03-14-2001 11:05 PM
.010 to .020 David. I do it regularly. This is why I so adamently always prefer and recommend solid lifter camshafts for performance engines. You can't do that with a juice cam. ------------------ Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member Fleet of FoMoCo products Moneymaker Bio US Class Nationals link
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Dave_C Gearhead Posts: 744 From: Gadsden, Al Registered: Aug 99
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posted 03-15-2001 11:11 AM
Ok, good deal. I think I will take .010 off the Comp Cam specs to start. I will set it at .016 and .018 cold. Thanks, David cole
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steve'66 Gearhead Posts: 6522 From: Sonoma,CA,USA Registered: Mar 2000
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posted 03-15-2001 11:55 AM
How is the performance curve affected by tighter, or loser valve lash? Won't a tighter setting increase duration, and lift? How does this help the bottom end? Thanks in advance for the tuning lesson! SteveW
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Moneymaker Administrator Posts: 19704 From: Lyons, IL, USA Registered: May 99
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posted 03-15-2001 12:56 PM
Looser for more bottom end, tighter for more top end. ------------------ Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member Fleet of FoMoCo products Moneymaker Bio US Class Nationals link
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Dave_C Gearhead Posts: 744 From: Gadsden, Al Registered: Aug 99
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posted 03-15-2001 02:54 PM
Oops. hould have clarified. I was thinking about the beginning of a pass at the track.When I come off the two step the converter flashes to 5400 by the time the car has moved more than a foot or so. So I need to tighten it up to improve the start of my run. It's goes to 5400, drops a tad on the shift, but otherwise stays between 54-6800 for the entire run. Later, David Cole
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steve'66 Gearhead Posts: 6522 From: Sonoma,CA,USA Registered: Mar 2000
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posted 03-15-2001 09:13 PM
Thanks for clearing that up Dave. I thought I was missing something. Sounds like your combo will stay in the "sweet spot" well. SteveW
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