Well good evening you Cats and Kittens it's your old Uncle ED. and I'm in need of some guidance from the gospel of the 8BA Flathead. As you may see in my avatar, I'm running an 8BA with 3 "American" Strombergs in my '32 roadster. The car runs fine until it warms up when it begins to feel like it has a miss. Soon after, it acts as if I were down a cylinder or seven! As I accelerate the engine sputters as if I had a plug wire arcing to the head no matter the RPM. When she's not under a load such as sitting in neutral or when I engage the clutch the engine revs just fine but begins to sputter once I let the clutch out and try to accelerate. If I shut the engine off for 20 minutes or so, it starts up and runs fine for 5-10 minutes then begins sputtering again. It seemed like it was an ignition problem (feeling as if I had a plug arcing out), so I adjusted points and went 4 degrees BTDC. Still no change, so I installed a Pertronix Electro-ignition. It helped A LOT but the car continues to have the same problem. Doesn't feel like a vapor lock. Running 4psi at the fuel block that feeds the 3 deuces. All 3 are synchronized with the secondary carbs running much leaner than the primary. The plugs appear slightly dirty (black but don't appear fouled) when during a flat out run I shut her down and coast to a stop to check them. No discrepancies to the wires but I am running the connections at the plugs without boots "Rajah" style. Engine temp is a constant 180. I'm thinking possibly when the engine heats up the connections at the plug(s) may be shorting? Feels like more spark than air and fuel. Any help would be greatly appreciated! Brother ED.
I had a similar problem. My problem was small rust particles clogging the fuel input at the carbs. The motor would run fine until the fuel in the float bowls ran low, then it would stumble. After sitting a bit and the fuel weeping back into the float bowls it would run fine again for a few minutes. Aaron
If you are running a fuel pump with a sediment bowl, is there "junk" in it? if not and you're running a filter, open it up and see what's inside. It could also be the coil (or possibly the condenser) getting hot and breaking down. Currently available are notoriously flakey. Sometimes you have to try multiples until you find a good one.
Venting issue? Take off the gas cap and see if anything changes. Probably a long shot but only takes a minute to check.
I had a similar problem and it turned out to be a coil that was weak when it warmed up. However, if you know anyone with an ignition scope you can quickly find out if the problem is ignition related.
My first thought was a bad coil or maybe a condenser. Best though to check the basics first make sure connections are tight and wiring in the ignition system good, including the wire and ground inside the distributor.
Sounds like a bad coil. As the coil warms up a bad one will sound just as you describe. If you have another coil laying around, 6 volt or 12 volt, doesn't matter swap it out. If it cures your problem head to the parts house. If it doesn' and you're running a stock distributor, check the wire that runs under the breaker plate and up to the points for bad insulation. A common problem.
Thanks, gentlemen, for all the guidance and support. Being a Strommie, it's not surprising that my center carb appears to have a very slight leak at the fuel bowl. So, I'm going to pull it apart and investigate. This is my first Flattie, I've been a Nailhead and early Hemi guy most of my life, but Mr. Aaron and Mr. Tubman you may be on to something. I had a .264 Nailhead that I kept finding scale and crap in the fuel line and carb bowls from crap in the tank. All that gunk would plug the jets on hard acceleration but once the bowl filled, it was fine. I thought it was an ignition gremlin until it wouldn't start until I blew the Monster from the Black Lagoon out the fuel line. I still haven't ruled out the coil or a wire- Ignitions are 90% of your "carb" problems! As I mentioned, I replaced the points with a Pertronix system which helped but didn't solve. The entire car is hand-formed aluminium over a '32 tub and the fuel tank is a hand formed aluminium cell. All fuel lines are stainless tubing except where it enters the fuel block. But it's back to stainless tubing from the block to each carb. The fuel line comes out of the tank through an electric pump and directly into a large canister fuel filter but after that, there are no additional filters. So, it could very well be a fuel issue with all that stainless tubing, but we'll soon find out. I'm in the middle of putting a new cam and timing set in the '34 but I'll keep you gentlemen informed on what I find. In the meantime, if anyone has any other ideas, I'm open to suggestion and I NEVER dismiss anything or anyone until I prove it to myself. I've seen some crazy sh*t so no suggestion is too wild. Keep 'em coming and if you think I could be of some assistance; please, hit me up. Much Appreciated and Thanks Again. Brother ED.
2 to 3 PSI Max on those strombergs. I run 2.5 on three 97's on my flathead. I used to run 4 and had nothing but issues. May not be your problem but noted none the less.
If fuel is leaking out of the bowl between the bowl and the top, you probably have a flooding issue. Bad needle and seat? Leaky float? Any black exhaust smoke?
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