Working on my '47. I've installed a Pertronix dizzy that was done by Henry at the Pit Stop for me. I've also gone through the carb and have new throttle shaft bushings and set to spec. The car has a stumble going down the road at light throttle (50 mph cruise). Then, when pulling a long grade it wants to ping. I've backed off the vacuum brake a half turn twice per suggestions I've been given. I've also found when I back out the mixture screws a half turn at a time I can make it smoother going down the road but still not 100%. I've checked for vacuum leaks, all new ignition wires, cap and rotor along with new dizzy. Anyone have some pointers? Thanks Don
Update.... I cleaned all the grounds, and have added a ground wire from the dizzy body to the battery. I retarded the timing 1/2 notch. Then I used a vacuum gauge and adjusted the carb till I got around 18-19" of vacuum. I've also checked for vacuum leaks. The car goes down the road ok now. You can still feel a slight burp at highway speeds intermittently. I have also had a hard time getting the idle speed set, seems to want to search and hunt once I set it and then go drive the car. When it sits and idles it kind of burbles. How much does the vacuum brake on the dizzy affect things? Looking for any advice. Thanks Don
The vac brake slows the basic curve. Reset timing to correct static timing as shown in '46 book, you don't want that reduced. Crank down brake fairly hard, go for a drive, loosen, repeat. Worry about phasing, timing triggering of electric box vs where the rotor is pointing...rotor mounting is rigid, but if triggering stuff is at wrong place multiple possible problems, starting with poor relationship to timing scale. Seach my posts on interference method and TDC...I thing you need to correctly mark TDC on your pulley so you can study your timing accurately with no points to indicate. You can find accurate TDC in five minutes, and need to since original timing method is out the window.
Ok, so where do I start off with the vacuum break? When you say screw it down fairly hard.....how hard? Sorry if I'm not getting it. Thanks Don
Heres a few links http://www.vanpeltsales.com/FH_web/flathead_tuneup32-48_221-239.htm http://www.vanpeltsales.com/FH_web/flathead_engines_distr-timing.htm http://www.vanpeltsales.com/FH_web/FH_37-48engine-rebuilding/v8_overhaul-forwrd-contents.htm
anyone know where to buy a ford service manual for a '47? The 1946 SERVICE (not overhaul) manual is reprinted as 1946-48 F-M-L service manual, easily available from all the Ford parts houses. The 1942 Ford army shop manual can be had from Military vehicle sources, and the 1946 Ford of Canada shop manual is reprinted (with added spec pages) as 1939-49 shop manual, also at all the resto parts places. Start by marking your TDC using interference check for accuracy. You need a reference point for timing light, as I don't think you can check firing point of Pertronix any other easy way. Once you have TDC, you can calculate and mark another 30 degrees or so on your pulley.
On checking or eliminating fuel supply as the stumble, 2 ways: First just pull out choke until idle gets unhappy and drive through the stumble point. Is it improved?? Next try stumble point twice more with accelerator pump in summer and winter positions to see if any change.
http://www.portrayal.com/ has the 1942 4dr Ford shop manual...call'em, I think the one on the Ford listing in their site is a lesser work. Oters will be at C&G Ford and other such places. Rumbleseat's book chapters are at bottom of this page: http://www.flatheadv8.org/rumblest/intro.htm
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