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8.1l Comp 270 Cam Problems

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Old Sep 30, 2010 | 08:25 PM
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Default 8.1l Comp 270 Cam Problems

I installed a Comp 270 cam in my truck a few months back and it floats valves... even with the reccommended Comp springs, retainers, locks and rotator eliminators. WTF! Will float the valves around 5200-5300. Noticed very small difference in power, has more upper-mid range but ran a slower 1/4 mile. When I ran it at the track it was tuned for the cam from Nelson. I then sent the tune back due to lean codes. Then I checked my fuel pressure and found it was low. Now I have a new f. pump and I am waiting on my tune. Why is this cam floating valves and lacking power? It should be at least equal in 1/4 mile et's with a perf. tune.
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Old Oct 1, 2010 | 06:25 AM
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bbc valves arent exactly light. Give me some more details on everything you did. specs of the cam. Did you put new pushrods in? Did you switch to adjustable valvetrain. Is your valvetrain geometry correct? I could go on but give me some more details
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Old Oct 1, 2010 | 06:48 AM
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Stock pushrods and rockers. Non adjustable. Cam is .510 lift 270/276 duration.
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Old Oct 1, 2010 | 06:50 AM
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are the stock rockers compatible with that cam?
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Old Oct 1, 2010 | 12:01 PM
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IM guessing its the rpms... stock revve limitor is 4800. or at least on my suburban it is.
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Old Oct 1, 2010 | 04:15 PM
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You have valve-train issues and just as xx_ED_xx eluded to about the geometry and weight and so, everything needs to be gone over. Beings you are supposedly running matching springs from Comp and still floating valves, and you mentioned using rotator eliminators, did you check the final installed height on the valve-springs or just drop them in and pray. You may be running with entirely too light of seat pressure if you didn’t or you just may have other issues if its truly floating the valves.

Last edited by 1Bear; Oct 1, 2010 at 06:39 PM.
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Old Oct 1, 2010 | 05:15 PM
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I will admit i did not have an installed height checker so i was hoping they were close enough for a relatively low turning motor. I only gained about 500 rpm over MUCH weaker stock springs. I know the seat pressure is probably twice of what the stock springs. And I am pretty sure they are floating by the noise comming from under the hood. Wich by the way sounds like a solid cam WAY out of adjustment. I was also told stock rockers would work.
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Old Oct 3, 2010 | 04:22 PM
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Told by who?
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Old Oct 3, 2010 | 06:38 PM
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Raylar
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Old Oct 4, 2010 | 10:23 AM
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8 lug, you know we need a sound clip of it ideling... i went to your youtube deal but i couldnt findanything about a cam.... nice burnouts though! lol
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