All new but black smoke issue - 06/17/18 03:28 PM
I’m having a problem and just not sure what to try next.
The car is: 1956 Townsman wagon, 265 V8 Power Pak Powerglide. EVERYTHING is freshly rebuilt last year. Engine, and that would include: new pistons, rings, turn the crank, all new main and rod bearings; lifters, valves & guides & springs, timing gears; oil pump, generator, distributor, carburetor, water pump, fuel pump, exhaust system, battery, trans, brakes, gas tank, tires (bias) - you get the idea - absolutely everything, nothing untouched. Totally, totally stock configuration, as built. NOS stuff or rebuilt originals instead of repops wherever possible. And then set up with original type vacuum gauges and instruments to exact factory specs as best as humanly possible.
And it runs great, just like the summer of 1956. Drove it from Ohio to New York last summer, and now a total of about 1,000 miles on it. It gets about 16 or 17 mpg, uses just a tad of oil, which yes I run with high ZDDP/zink content.
So here’s the problem - going up a hill, or jumping on it for passing gear at 35 or 40, and the secondaries open up - I get a pretty good shot of black smoke. Soot. Not blue, not gray or white - black, like unburned fuel. It is also very sooty when I first start it and the choke is still on. I get a big shot of black for the first few seconds.
Most stuff I did myself, but various things were sent out for better experts to re-do. One such was the carburetor, a Rochester 4-jet 7008737, original to the car. It came back real pretty and I put it on.
Naturally my first thought was the carb was not right. So I finally found and bought a second 1956 Rochester 4-jet, got the right kit and meticulously rebuilt it myself. Put it on a few days ago. And I get the same results! The choke opens fully when warmed up, the floats are set right, the jets are right, the accelerator pump is right.
What’s going on, what do you think to look at next?
I have thought maybe the spark isn’t hot enough. I’m running AC R45 plugs (original equipment), and the coil and points etc are all new and set up as they are supposed to be.
Going down the road all warmed up the problem is not apparent. But when people are following me, I always get comments about “hey, when you push on it you really get some black smoke!” So it’s there. Not sure what to try next. Many thanks for your thoughts…
The car is: 1956 Townsman wagon, 265 V8 Power Pak Powerglide. EVERYTHING is freshly rebuilt last year. Engine, and that would include: new pistons, rings, turn the crank, all new main and rod bearings; lifters, valves & guides & springs, timing gears; oil pump, generator, distributor, carburetor, water pump, fuel pump, exhaust system, battery, trans, brakes, gas tank, tires (bias) - you get the idea - absolutely everything, nothing untouched. Totally, totally stock configuration, as built. NOS stuff or rebuilt originals instead of repops wherever possible. And then set up with original type vacuum gauges and instruments to exact factory specs as best as humanly possible.
And it runs great, just like the summer of 1956. Drove it from Ohio to New York last summer, and now a total of about 1,000 miles on it. It gets about 16 or 17 mpg, uses just a tad of oil, which yes I run with high ZDDP/zink content.
So here’s the problem - going up a hill, or jumping on it for passing gear at 35 or 40, and the secondaries open up - I get a pretty good shot of black smoke. Soot. Not blue, not gray or white - black, like unburned fuel. It is also very sooty when I first start it and the choke is still on. I get a big shot of black for the first few seconds.
Most stuff I did myself, but various things were sent out for better experts to re-do. One such was the carburetor, a Rochester 4-jet 7008737, original to the car. It came back real pretty and I put it on.
Naturally my first thought was the carb was not right. So I finally found and bought a second 1956 Rochester 4-jet, got the right kit and meticulously rebuilt it myself. Put it on a few days ago. And I get the same results! The choke opens fully when warmed up, the floats are set right, the jets are right, the accelerator pump is right.
What’s going on, what do you think to look at next?
I have thought maybe the spark isn’t hot enough. I’m running AC R45 plugs (original equipment), and the coil and points etc are all new and set up as they are supposed to be.
Going down the road all warmed up the problem is not apparent. But when people are following me, I always get comments about “hey, when you push on it you really get some black smoke!” So it’s there. Not sure what to try next. Many thanks for your thoughts…