Senior Tech Team
Join Date: Apr 2012
Location: Yerington, Nevada
Re: Holley problem: leaking power valve?
I only dress the threaded metering block boss ends of the body for flat, as the screw hole bosses bend easily when some Gorilla uses 57 foot pounds of screw torque to hold a leaky metering block in place after it was bent so far out of shape it won't work.
For the metering blocks, I lay them out with their bent curvature up in the center, and VERY LIGHTLY press them back flat. Way too easy to turn a metering block into instant junk with other methods.
Before I get plastered by everybody for what I am saying, please remember, I worked in the Pro-Stock carb dept of Holley Racing for 5 years, band sawing Dominator's apart, making them into "Split Duals", then helping tune them on race cars.
As far as the leaking PV, a few ways to get them to leak, frm the wrong gasket, to the over tightening in the metering block, but what aI was asking, and got the right answer, was, did the vacuum diaphragm get punctured, was there fuel leaking into the manifold? I have seen a very small tear in a PV diaphragm load the entire bowl volume down to the hole, into the intake manifold, cylinder, and oil pan. NONE of ahy of that is good at all. Glad that wasn't the issue.
The PV save device is simply to make sure the PV diaphragm doesn't have failure issues if the engine backfires. The reverse pressure can easily kill the PV diaphagm.