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Old 05-22-2007, 02:32 PM   #1
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Default Odd experience with rockers

Upon installing a YT roller rocker, it compressed the valve spring ~1/8". I installed as directed:

"Tighten to the starting point of zero-play (push rod cannot easily be turned by hand), then torque to 25 ft-lb."

At that point, most of the any play in the pushrod is gone, but the valve is slightly open. If I give it a couple minutes and turn the engine over by hand a few times, it seems to settle in and let the valve close. I reinstalled the stock rocker and it acted the same way. Is this normal?
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Old 05-22-2007, 02:55 PM   #2
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Sounds like the hydraulic lifter got pumped up when the rocker was removed, but went "back to normal" after a few revolutions with rockers replaced.

But, how the heck does a lifter pump up if it'* just sitting there? I suppose there'* a piston and spring inside the lifter that "sucked" oil in after the tension from the rocker/pushrod was removed?
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Old 05-22-2007, 02:57 PM   #3
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This engine is on a stand with no oil pan and likely very little oil in the passages.

I should say, this is a fresh reman motor.
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Old 05-22-2007, 04:01 PM   #4
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Sounds like the lifter wasn't on the base circle portion of the cam lobe at first?
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Old 05-22-2007, 04:16 PM   #5
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I verified that is was before I torqued it down. I tried it on other cylinders as well and had the same result.
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Old 05-22-2007, 05:19 PM   #6
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I talked with John on the phone about this last night. Keep in mind these are YT 1.7 ratio rockers. The pedestal is integral to a valve cover spacer. All once piece. The only reason I can figure why they would raise the cover is because the snout of the rocker arm is thicker (higher profile, not tapered off) than my 1.8'*.

The suggestion I made was to rotate the engine through with them torqued, and use an air chuck adapter in the spark plug hole and a compressor to see if they're actually fully closed or not.

John, are you going to try this tonight? Your pushrods should be able to spin with the valves fully closed as well, with just finger-force, especially since the lifters have never been pumped up before.
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Old 05-22-2007, 05:24 PM   #7
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I'll get the adapter on the way home today. I can spin the pushrods still with my fingers, but it'* not what I would call free, it'* pretty stiff.
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Old 05-22-2007, 08:15 PM   #8
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No dice on the fitting. Went to Napa, Lowes, a large local hardware store, then Advance. Noone even gave me a knowing look as to what I was talking about.
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Old 05-22-2007, 09:03 PM   #9
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Most of them don't know what it is. But I can tell you it'* a normally stocked item at my local Autozone, NAPA, and CarQuest.
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Old 05-23-2007, 01:49 PM   #10
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The same fitting can be found in any compression testing kit.
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