I drove around to day in the jeep to get vacuum readings for a new power valve.
Cruse in 1st to 4 th gear: 15 in Hg
Cruse in 5th gear: 7 in Hg
Moderate acceleration in 1st to 4th: 7 in Hg
Heavy acceleration in all gears: 4 in Hg
Idle: 19 in Hg
I would like to find a 2 stage valve opening at 12 or so and the second stage at about 5. This
should keep me out of the power valve in all but 5 th gear and that should change when I
regear the diffs. I am however still looking for a source for Motorcraft/ Autolite Power
valves. I have attached a drawing of the 2 stage Power valve and would be interested If
anyone could compare it to a Holley 2 stage Power valve, and note any differences, I would
appreciate it. Its a long shot but they may be the same.
I managed to remove the top end cap off the top end of my spare power valve and a
spring and some kind of little piston came out. The rest of the mechanism seems to be under
the bottom end. I could not get the bottom screw out and was not willing to use heat since
the jeep seems to like this valve better. I put the top screw back in to the same point, I do not
want to adjust it my self until I have had one all the way apart and know how it works. the
one I am currently running marked 167 seems to flat spot on acceleration at about 10 in Hg.
During this flat spot if I pull the choke the jeep accelerates. I suspect that this power valve
does not open till much lower and that is why pulling the choke (richening the mixture)
TiminMb, I would be suppressed if the 16 on your power valve means it opens at 16 in Hg.
Holley lists there valves on there web page and the highest they list is 12.5. I know they
may be different valves but it is hard to imagine that much difference. Who knows I am just
speculating. On your search for main jets I sent a parts request to
about 4 months ago and they informed me that
they have them in sizes 38 and up for $7.00 a pair. They also have a nice carb identification
page that can be useful. I have sent a request as to what if any power valves they have and
am waiting for a response. I will post what I find out.