Quote Originally Posted by stotzbotz View Post
Hello friends. I am anxiously awaiting the call from the machine shop who has my FE390 heads after my recent valve guides leakage problem. I wondered if you experts could give me your opinions about something I was told by a gentleman who has built and raced several of these motors over the years. It seems as though when my engine was losing oil some due to it being blown out the exhaust from the leaking valve guides, my oil pressure gauge was fluctuating quite a bit once I was about a quart low. If there was not a full 6 quarts flowing through the motor the gauge would go back and forth between 40-70 psi when I was going down the road and pushing roughly 4000 rpm. I'm fairly certain I have a high volume oil pump in this motor as the previous owner stated. I do have solid lifters, high performance cam and valve springs. This motor was recently rebuilt and has been bored .060 over. Cam bearings were replaced. Anyway the gentleman told me that with these FE motors they tend to pump more oil into the valve/rocker/head area than needed and less is being pumped into the crank area causing several things to occur that could be causing my problem. Has anyone ever heard of clogging the hole in each head which I believe is the one that the rocker rail bolt with the hole in it is used to pump more oil into the heads? Since I'm getting ready to put them back on the motor it will be easier while they're off to do this. I was told this will keep more oil downstairs but still allow enough to come up and keep the rocker rail area happy. Any guidance in this area would be greatly appreciated and as always, thank you very much for taking the time to help me with my issues with this motor.
Tap the hole supplying oil to the stand/shaft (on top of the head). It's about 5/16" and that's tap drill size for a 3/8"-16 tap. Now you can thread in a short 3/8 set screw, you just don't want to use hardened ones. You can drill maybe a 3/32 hole thru the set screw this size will be a good starting place. If you want to restrict more you can remove these set screws and install another set with smaller holes. they screw in and out with a 3/16 allen wrench after you remove the rocker assembly, no need for loc-tite the set screw is trapped in place.
But all this is really only a Band Aid to loose clearances around the rockers, you should have no more than say .004, make sure the holes in the shaft are down. your HV pump wouldn't drain your pan if it had no where to pump it out. remember pumps don't make pressure, restriction does. Hope this helps