03-10-2002, 10:24 AM
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CC Member
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Join Date: Apr 1999
Location: Denver, CO,
Posts: 99
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Not Ranked
Breathers
If you rely only on the valve covers for breathers, you may have problems blowing oil out the valve covers at higher RPM's due to blow-by. Pressure in the crankcase will limit the amount of oil that can drain back even when restrictors are used. I use a breather on the oil fill tube and the goose neck on the back to allow the block to breathe and both my valve covers are sealed up. With a high-volume pump I have no excessive oil problems with my Dove heads. If you run a PCV valve, the style that fits in the breather hole in the back of the intake will probably help scavenge the block better than a valve in the valve cover.
I have heard that excessive rocker arm clearances can also lead to too much oil in the heads. Apparently, some brands of rockers come from the factory slightly oversized. Not sure if this is true but it kinda makes sense.
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