The Ford Barn

rhpope · 06-10-2024, 09:01 AM

59A Flathead that was built by someone else.

This is what I was told that engine is internally:
276 ci
Isky 400 Jr cam. It has a bit of a rough idle so it seems like it is a 400jr cam or least something comparable since I can't verify the cam without going into the engine.

This is what I can say visually about what is on the engine:
Edmunds 2x2 intake
Stromberg 97 carbs
Edmunds heads
8BA timing cover with later model Dual Point Mallory distributor.
Fenton exhaust manifolds
2" exhaust to Porter mufflers

The engine seems to start up and run fine at idle and in the lower RPMs. The lower RPMs range that I mean is probably up to about 2000 RPM or so. But when accelerating harder or longer in each gear so that the engines revs up into the 3000+ rpm range, the engine's power falls off like a flat spot and then it starts loading up like it is getting too much fuel. It kind of jerks a little too. All of the spark plugs are sooty and black showing that is running way to rich.

When parked and just free reving the enigne, you see and hear the same thing. Low RPM's seem ok, but higher RPM's it is loading up, popping, and extremely rich exhaust smell.

What I have done so far to diagnose the problem without any real change:

1. Carbs had stock jets and power valves in them (45 Jets, 65 PV's), changed to 43 Jets and 71 PV's

2. Checked distributor timing. Recurved for better advance curves, Now has 22 degrees advance all in by 2500 RPM and 4 degrees initial timing. New points and condenser (tried three different brands of condensers just in case), but I have no way to test the condensers other than to make sure that they are not shorted to ground. It has solid core plug wires and checked each to make sure they are in good shape by checking resistance (less than one Ohm each, continuity, and none are shorting to ground.

3. Replaced coil with a new Beru Blue coil and made sure that the positive lead to the coil is 12V for the Beru Blue coil to work properly. I bypassed the ballast resistor on the original coil on the car. The Beru Blue Coil is the same as the Bosch 00012 coil and does not need ballast resistor.

4. Checked fuel pressure, have about 2.5 psi at the carbs with engine running at idle. Drops some to about 1-1.5 psi while reving it up high.

5. Still ran the same. So, I blocked off each carb individually to see if the dual carbs were the problem or to see if one or the other carb has an issue. Still ran the same.

6. Check the compression on each cylinder with the engine at operating temperature. All are 140 +/- 10 psi.

7. It had NGK B4L plugs in with only a few hundred miles on them. All of them are black and sooty. They are the shorter reach plugs for iron heads. I put new plugs in it just to see if there was a difference, but no change really.

It only sems slightly better with all that I have done where the extreme rich smell isn't quite as bad, but is still pops and loads up reving it up. The new plugs got black really quick.

What am I missing? I'm at a loss and looking for suggestions.

06-10-2024, 09:01 AM	#1
rhpope Junior Member Join Date: Aug 2010 Location: North Carolina Posts: 23	59A Flathead Running Rich, Need Help 59A Flathead that was built by someone else. This is what I was told that engine is internally: 276 ci Isky 400 Jr cam. It has a bit of a rough idle so it seems like it is a 400jr cam or least something comparable since I can't verify the cam without going into the engine. This is what I can say visually about what is on the engine: Edmunds 2x2 intake Stromberg 97 carbs Edmunds heads 8BA timing cover with later model Dual Point Mallory distributor. Fenton exhaust manifolds 2" exhaust to Porter mufflers The engine seems to start up and run fine at idle and in the lower RPMs. The lower RPMs range that I mean is probably up to about 2000 RPM or so. But when accelerating harder or longer in each gear so that the engines revs up into the 3000+ rpm range, the engine's power falls off like a flat spot and then it starts loading up like it is getting too much fuel. It kind of jerks a little too. All of the spark plugs are sooty and black showing that is running way to rich. When parked and just free reving the enigne, you see and hear the same thing. Low RPM's seem ok, but higher RPM's it is loading up, popping, and extremely rich exhaust smell. What I have done so far to diagnose the problem without any real change: 1. Carbs had stock jets and power valves in them (45 Jets, 65 PV's), changed to 43 Jets and 71 PV's 2. Checked distributor timing. Recurved for better advance curves, Now has 22 degrees advance all in by 2500 RPM and 4 degrees initial timing. New points and condenser (tried three different brands of condensers just in case), but I have no way to test the condensers other than to make sure that they are not shorted to ground. It has solid core plug wires and checked each to make sure they are in good shape by checking resistance (less than one Ohm each, continuity, and none are shorting to ground. 3. Replaced coil with a new Beru Blue coil and made sure that the positive lead to the coil is 12V for the Beru Blue coil to work properly. I bypassed the ballast resistor on the original coil on the car. The Beru Blue Coil is the same as the Bosch 00012 coil and does not need ballast resistor. 4. Checked fuel pressure, have about 2.5 psi at the carbs with engine running at idle. Drops some to about 1-1.5 psi while reving it up high. 5. Still ran the same. So, I blocked off each carb individually to see if the dual carbs were the problem or to see if one or the other carb has an issue. Still ran the same. 6. Check the compression on each cylinder with the engine at operating temperature. All are 140 +/- 10 psi. 7. It had NGK B4L plugs in with only a few hundred miles on them. All of them are black and sooty. They are the shorter reach plugs for iron heads. I put new plugs in it just to see if there was a difference, but no change really. It only sems slightly better with all that I have done where the extreme rich smell isn't quite as bad, but is still pops and loads up reving it up. The new plugs got black really quick. What am I missing? I'm at a loss and looking for suggestions.