Reading all this makes me happy for my efi conversion. Playing with 3 WDO carbs was fun and a good learning experience, but I don’t miss it. The WDO was superior the the EE14, but neither are as good as efi. That’s not to say the efi didn’t take some adjusting… iac ramp down was off and it would stall coming to a stop, but that’s fixed and it drives like a dream and not a single vapor lock issue now.
Quote:
DavidPackard wrote: Other WDO musings:
For the accelerator pump to work well enough neither valve (ball or needle) needs to seal perfectly. As such, I rarely pull the trash screen just to change the ball. I normally have my Carters apart on about a 3-4 year cycle, for nothing more than a refresh of the fuel shut-off valve (needle and seat), and plunger (acceleration pump), so they are not normally gummed-up all that much.
In the past I’ve intentionally adjusted the anti-percolation valves to close late just to see what the symptoms would be. The engine would not transition from the low speed circuit to the main circuit with that adjustment out of wack, so the car was limited to about 20-25 mph. I guess if the AP adjustment was close enough to specification the transition would possible, but perhaps rough. Something to think about if there is rough running during the transition speed.
I’ve also messed around with the ‘finger’ (set with tool T109-27, 72, 113, or 117S depending on ‘tag number’) that sets the minimum metering rod position as a function of throttle position. The adjustment that I tried would produce a lean condition, which resulted in a ‘flat spot’ during transition, not as bad as the AP adjustment, but a ‘flat-spot’ none the less. Given the alcohol in fuel these days perhaps this adjustment should be biased a tad rich. I could send a drawing on how to make a gauge out of round stock. What you need is the ability to grind/file a point on one end of the tool (angle TBD), and a means to measure the total length of about 2 ¼ inch (varies by tool number). The tool measurement needs to have an accuracy of 0.005 – 0.010 inch. Plus with homebrew gauging if you want the adjustment to be 0.010 inch more than spec just make another gauge, and zero in on the mixture that has the best transition, and has a smooth transition to and from coasting with OD locked-out.
Some Carter repair manuals suggest a new vacuum piston spring at every access, but the kits I’ve bought lately didn’t have that spring. I currently have one #4 stainless steel AN washer (0.040 thickness) shimming the spring, which would be in the rich direction. That seemed to help the transition (especially at very low acceleration rates) well enough to justify a future ‘two washer’ test. I don’t know if I’ve enrichened the mixture beyond the original intent, or just corrected the mixture closer to spec. The time in service of the spring I have is unknown, but could be eligible for social security.
Back to the AP valves. I have a WDO intended for a Hudson It was in really bad shape, but while the AP valves looked okay, and open/closed okay when I disassembled them (disassembly of the valve is destructive), one of the internal return springs was broken . . . it looked like a corrosion failure. Those Hudson AP valves have a second life as a set of dummy valves that I currently have in my ’48 (remember a WGD doesn’t have AP valves and my modified WDO doesn’t either). I know if both AP valves remain open, or are grossly late closing, the car will be limited to the low speed circuit, but if one valve got ‘hung-up’ we would likely have, because of the dual plane manifold, a 4 cylinder engine running correctly, but the other 4 cylinders running lean, perhaps lean enough that the ignition is suppressed. Just a lot of cylinder washing, but not a lot of power. I’m still chasing what was wrong with my ’48 when it was running really bad for about 20 minutes, and then cured itself. Because of the timeline of what was going on during that outing one AP valve leaking is still on the list of possible failures, but will not likely be proven/disproven because the evidence is long gone. Installing the dummy valves is an attempt to turn off that failure mode. The thread of the AP valve is a common standard, so an Allen set screw could be used as a plug, but if the carburetor police look down the air horn my dummy valves look like the real McCoy.
Back to the Hudson carburetor. Carter seems to have an endless number of main jet/metering rod combinations, and for some reason the main jet diameter is not a common twist drill size (not fractional, number, or letter). The Hudson jet/rod sizes are nothing like Packard combinations, but if the Hudson main jet is paired with a Packard metering rod I believe the new combination will richen about one ratio unit, or just about what was lost when alcohol was added to the fuel. That’s something else I would like to test.
That two barrel Holly EFI is looking real interesting . . . except I’d like to keep the car electrical system 6+.
