INTERNAL ENGINE MODIFICATIONS Valvetrain |Heads | Strokers | Design | Assembly

Having valve float issues

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Old Oct 8, 2011 | 07:57 PM
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Default Having valve float issues

Went yesterday to get a retune after the install of my Ls6/243 heads on my S10.Its a 5.3 with an ls6 intake,243 heads milled .30, Comp Cam 222/228-581/588 on a 112,Ls7 lifters,7.350 Comp hardened push rods,Harlan Sharp 1.7 RR,Comp 918 springs at 6400 rpm tuner says there was some valve float.Never ran into to this before with the older set of 918 springs on my stock 706 heads.6400 rpm is my shift points.What could be my problem?Is there something I missed during the head swap?Any help or suggestions would be greatly appreciated.Mike
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Old Oct 8, 2011 | 09:13 PM
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did you have the roller rockers on the old heads? if not then what is the "lift" gain using those rockers on that cam? would it be too much that the 918s cant keep pressure on the valves?
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Old Oct 8, 2011 | 09:40 PM
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Yes,used the same roller rockers on the 706 heads and didnt have any issues.Been running them for 2yrs.
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Old Oct 8, 2011 | 09:47 PM
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are those the same pushrods you had before the LS7 lifters? if they are then you have to look into if the pushrods are long enough bc the LS7 lifters require more preload, if not then hell im out of options other than the springs are weak which i doubt since they are new.
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Old Oct 8, 2011 | 10:05 PM
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I had 7.4 pr with the 706 heads and the ls7 lifters.I'm going to go to the shop in the morning and pull the valve covers and do some checking.This is not the 1st time I've had problems with the comp 918 springs.
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Old Oct 8, 2011 | 11:07 PM
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Ditch the 918's and get some PAC 1218's or Manley Nextek duals...
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Old Oct 14, 2011 | 07:19 PM
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So pulled the valve covers off and checked the roller rockers,pushrods etc,didnt find anything wrong.Has anybody else have valve spring float with the comp 918 valve springs?Need to fix this issue real soon before Oct 29th.Mike
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Old Oct 14, 2011 | 10:14 PM
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Originally Posted by chevysten
So pulled the valve covers off and checked the roller rockers,pushrods etc,didnt find anything wrong.Has anybody else have valve spring float with the comp 918 valve springs?Need to fix this issue real soon before Oct 29th.Mike
Holty recently had a nagging misfire that he remedied by swapping out his low mileage Comp 918's, and many, many folks have had worse luck with them breaking, dropping valves, etc.
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Old Oct 15, 2011 | 02:48 AM
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Well for the peace of mind I'm just going to remove the 918's and install some PAC 1218's
I'll report back and let you know if that worked.Mike
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Old Oct 15, 2011 | 05:01 AM
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Whats oct 29th?
They have a set pac1218s for sale (brand new) in the for sale section
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