I have a ford model b motor that I decided to hop up this winter. Hopefully made a good decision. I installed a scalded dog intake, headers, fs electronic ignition,mechanical fuel pump, and a Ford 94 carb. I jetted the carb with .044 jets and the power valve is 5.5. The car runs like crap. It backfires and does not idle. I don't know if it is timing or carburation. I know there are a lot of successful people doing this and need advice. Let me know your thoughts. Thanks, Brandon
FS ignition, no points, right? Looks like a stock head. Sent from my DROID device using the TJJ mobile app
Double check your timing since you've had the distributor out. http://www.fordgarage.com/pages/ignitorB.htm This is a link that shows how to time the pertronics ignition in a model B It has photos and everything. Eliminate timing and if that doesn't then move to carburation and no intake manifold leaks. That's how I'd approach it Good luck and let us know how it turns out. LJ
I ran a B in my Model A pickup with a Winfield head, Mallory dist. Ansen intake, 94 carb and a header. I ran 10 degrees advance at idle which put it at about 28 degrees total advance. Backfire sounds like a timing problem, I made a timing pointer from a piece of metal, mounted it under a timing cover bolt, used the timing pin to find 0 degrees and filed a notch in the crank pulley. I measured the crank pulley and figured what 10 degrees was and filed a second notch and used a timing light. I think 10 degrees was 1/4 inch but was several years ago and the engine is long gone now.
Looks like a nice setup. When we put a B in my sons speedster we used an FS mechanical advance and used a timing light to set it up. Don't forget that with the B timing cover there is more advance than a stock A. You're already starting out at 19 degrees advance with a B, not at TDC. I've found that what I think is a carb problem is usually timing or electtrical related. Here's a pic when we first set it up with dual 94's with their power valves blocked off. It now runs with a single intake with a stromberg 81.
You say mechanical fuel pump so is the diaphram in the pump ok your carb is above the tank so it could be the old fuel pump diaphram has a hole and not pumping properlly
I had a similar problem with my Ivory Speedster; B Engine, FSI Ignition, Thomas 7:1 Head and with two 94 Carbs. There were two problems that made it difficult to solve. First the Plug Wires were very high resistance. They were Changed to 1K ohm/ foot wires and that helped. The second problem was the Power Valves in the 94s. I tried blocking one one the carbs power valves and using different size (2.5, 3.5) in the other carb. I even completely blocked off one of the carbs and used only a single 94 with different power valves. I could not get it to run right. I have installed two Stromberg 81 Carbs, and it now runs fine. I installed the higher resistance plug wires just to check, and it ran poorly. Now back to the 1K ohm wires and we are good. I know other folks use 94s and they work for them. I just had a problem getting them to work and gave up. That is the problems I had, but yours may be different. Just wanted to let you know the problems I had and how they were fixed. Bob
Thanks Bob. It frustrating trying to figure it out. It seem like it should be a simple fix. Weather is getting better and I turned my daily driver into a car that looks cool but can't drive. Still better than no car at all. Need a break from it. Drives me crazy.
If it backfires and won't idle.....it's timing or a related ignition problem If you have a fs Ignitions dizzy, then it ain't a problem with that. Mel knows ignitions for Bangers So it's timing, or leads Problems above idle, then look for intake side issues. Carby. Fuel feed But backfiring and idle issues, look for ignition Bigger picture, you have improved your intake and exhaust airflow, and you have a solid ignition. Your next step is to get the engine doing more with those solid foundations Once you have it running nice, you need to look at your cam and compression. More of both But not too much of either
Are your wires plugged into the right location on your distributor? The pictures of Brian's and yours are different. You have the firing order correct 1-2-4-3, just wondering if your wires are off.
I know very little about 94's, but the starting point on main jets should be the stock jets that were originally in the carb. For power valves you will probably (?) need to go to smaller ones or at least ones that open later, vacuum-wise. Your problem could be either jetting or ignition. #44 jets sound like Stromberg jets.
With all due respect that's not necessarily true. Letting the engine breath a bit better with a stock cam and compression will give improvement. I have an A engine in my speedster running an 81 carb with headers and a downdraft manifold with stock head and cam. It idles and runs with no problems at all. With that being said I DO agree though that a 5.5:1 head would help.
A simple mistake is to install the distributor 180 degrees off. Find TDC, remove the cap and make sure the rotor is pointing at number one at the lower right. Then make sure the firing order is 1, 2, 4, 3.
Just finished my day up. Pulled the distributor out and started from scratch. I re timed using the pin with #1 piston at top dead center. It does not seem to backfire. Pops a little at the end. It runs good when you keep giving it fuel. If you you try to hold the fuel down as if you driving(say half throttle) it chokes it self out. I am thinking about either getting the smallest jets I can hopefully, in the .030's or plugging the power valve. Maybe adjustable jets? It sounds decent when revved . I am not giving up with this combo. Stubborn and put way to much money in it. It has been done for years. I'll keep you updated after I eat my corned beef and cabbage. Happy St. Patrick's Day!
Does the engine smoke? How do the plugs look. I think you might stillm have a timing problem. If someone put a model A timing cover on your engine, engine would time at tdc with the pin. This is not correct for a B distributor. I would suggest loosening the distributor cam and turning it a small amount counter counter clockwise ( 1/4 inch of rotor or so) to advance and see if it runs better or worse. Model A's run like crap if they are retarded. John
Make sure your fuel line from the pump to the carb is far enough from the header not to atomize the fuel. Also, a good idea might be to get a pressure guage in the fuel line from the pump to the carb. Did you use a coil intended for use with or without a ballast resistor?
The engine does not smoke but the plugs are black. Obviously to rich. The coil came from fs with the distributor. I am looking into maybe hotter plugs. If anyone has ideas on them let me know.
depending on the head, you could start with AC R44XLS; R=Resistor, 4=14mm, 4=heat range, XLS = extra long seat and then move up or down
Don't go smaller on the jets go bigger. It sounds decent when you rev it because the power valve is opening and richening it up. When using a carburetor from a larger engine air moves through it slower causing the engine to get less fuel. Switch to 50 or 52 jets and run your 5.5 power valve, it should run nice.
Once you are sure of ignition timing...JETS. 44 is off the map, go back to stock or no more than one step lean (due to very short passages here)...what you took out, likely around 049. I can look up stock if you post what model (marked on driver side of bowl). Don't worry about PV until you have it running well at low speed/low throttle opening. Idle is a different circuit, adjust he mixture screws, speed will change along with mix and you need to go back and forth, tinkering the mixture (SLOWLY so engine can react) and resetting the idle speed scre as you go. You just fell it out until engine sounds happy and you can't turn screw in any further without engine worsening. 44 is hopelessly lean.
If you only do one thing to a flathead four, INCREASE COMPRESSION. If you do other things to go fast, INCREASE THE COMPRESSION first and get the kit to time it with a light