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Valve-train issues, need help.

Old Apr 5, 2006 | 05:01 PM
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Default Valve-train issues, need help.

If you don't get it right you don't have the correct seat pressure or pressure through the valve events and you risk valve float and destroying the cam lobes and lifters.
I have about 3,000 miles on a freshly built block with a new G5X4 cam and new Comp 850 lifters. I used Comp dual springs that have been on the heads for a few years, but im not sure on how many miles they have on them.
I had it dynoed last week and it had major valvetrain issues at higher rpms. I got 367rwhp, with the mods below. I didn't get a copy of the graph, but basically at high rpms the horsepower just dives down.
I am changing the heads as soon as my ETP small bore 225's arrive. I opted for the upgraded dual springs that are good up to .650 lift, and will make sure I check for pushrod lengh. I am changing the lifters to the Comp R lifters(yes I have read all the bad threads about them).
I am wondering can the cam be damaged from this possible valve float? Would one be able to tell when removing the heads and lifters if the cam lobes are bad?
They dyno operator told me the valvetrain had some type of ticking sound that didn't seem to sound normal. Any advice? thanks
Jimmy
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Old Apr 5, 2006 | 05:32 PM
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You can damage the cam with float. If it was just a couple of dyno runs it is probably OK. If the springs are weak, you run the risk or breaking them. You may want to at least pull the valve covers and make sure they are in one piece. Where ever you ran into the float, stay well below that RPM until you change your heads to prevent cam or lifter damage.
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Old Apr 5, 2006 | 06:13 PM
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You could check the lobes with a dial caliper for uniformity.
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Old Apr 5, 2006 | 08:16 PM
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Well, I have put about 3,000 miles on the setup. I have been WOT more than a handfull of times. So to inspect the cam it would need to be pulled out?
Well, we will be pulling out more than the valve covers. The heads will be pulled to swap them out to new ones.
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Old Apr 5, 2006 | 08:56 PM
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If you are pulling the heads and lifters, might as well pull the front cover and pull the cam. It will be easier to see any damage if it's in your hand and you can check runout too.
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