1940 Flathead, offy dual intake, stromberg 97's, mallory dual point, offy heads, Isky 400 jr cam. was running great then when I started it, it popped and backfired and would not open up. I discovered it was running only on the odd cylinders, sporadic firing on odd cylinders and not firing at the proper time. Points set at 22 Thousands, Carbs clean, floats set properly. Head scratcher for me. Been working on these things for 40 years and this is a first. It idles fine, by the way, soon as it comes off Idle it just won't fire properly on 2,4,6 & 8.
4 lobe cam in dist or 8 lobe? dirty points? take a point file to them, or an emory board stolen from your wife followed by a business card to glean the gravel from the sandpaper out, then re gap (I always use .020) and see how it goes. when you pull the wires off the non firing cylinders, is there spark there at the plug wires??
I had a firing problem on my flatty with an early Mallory dual point. Tried everything except plug wires because I had put them on new.... They were Accel silicon 7mm resistor type wires. It would miss under load but idle fine. Finally found one or two pins that the wires push onto had corroded and was arcing up the wire. Pulled some old original '51 Ford wires off a couple old engines and threw them on there and it runs like a top! Thoroughly cleaned all the pins of course, before I changed wires and cut the ends off the bad wires but no good until old Ford real wire plug wires did the trick. I have also had bad condensors in flatheads that the car would start but would NOT rev up. Dave EDIT: Mine is an 8ba block and Mallory for 8ba. Is yours down low on the front like '48 and earlier or up front on the right side like mine?
It's on a 40 block, so down low behind the fan. I replace the 400mfd condensor, pulled the wires from the metal tubes and seperated them, set the points at 22 thousands per Mallory they look new no pitting etc. Still only the even plugs, swapped the even and odd plugs, no help. Still scratching my head, waiting on a new crab cap to come.
Points are like new with no leakage, set at 22 thousands as Mallory suggest, Pulled plug wires out of the metal tubes, no change, new condenser, Have a cap coming with rotor.
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