At a loss. 1949 Ford flathead V8
 

Cannot figure this out. Just purchased 1949 Ford flathead V8. In my youth, I built 5 and thought I knew most everything about them. I put on new Bully carb from NCI, points, plugs, condenser, checked the timing, pluged up the vacuum hose to the wipers. The owner died last october so I drained the plastic gas tank thru the drain plug, put in fresh non ethonol along with a can of Seafoam. Did a compression test, all cylinders 90-95. Did a continunity test with inline spark plug checker. At idle the enging lopes badly, on the highway, I get backfires thru the exhaust upon acceleration. The engine has little power. I have tried advance timing, have retarted it. My 83 year old mind can't figure this one out. Would welcome suggestions.

Re: At a loss. 1949 Ford flathead V8
 

It's possible one of the problems is the new condenser. A lot of folks report them being bad right out of the box. I believe NAPA still sells a decent one.

What spark plugs did you use? Did you check the gaps on them and adjust accordingly?

Did you also trace the spark plug wires to ensure they are correctly routed from the correct cap location to the correct cylinder?

It didn't say if you replaced the wires. If not, try to find a dark location and look at them with the car running. It could be possible that one has rubbed through and is shorting out while running. The dark location will show the short with a flash.

This is the carb you have, correct?

https://nationalcarburetors.com/NEW-...72_p_2500.html

Re: At a loss. 1949 Ford flathead V8
 

Lots of "new" condenser problems have been mentioned here as Tim noted. Are your wires as shown below?


https://fordfiringorder.com/wp-conte...arkplugs-2.jpg

Re: At a loss. 1949 Ford flathead V8
 

Thank you both for your responses. I used Autolite 216 spark plugs and NAPA points and condenser. Yes, I have traced all of the wires and the timing order is correct. I used NAPA points and condenser. This beautiful show car was running this same way when I bought it. I was confident that could easily fix it with all of the above new parts. I did a vacuum test also on intake vacuum and it ran steady between 25 and 27 pounds.

Re: At a loss. 1949 Ford flathead V8
 

About the distributor. Are you sure it is advancing with RPM increase? Attach your timing light and give it some gas to check that it is advancing.


Oxygen - Fuel - Spark


Glenn

Re: At a loss. 1949 Ford flathead V8
 

Pardon my ignorance, what is a Bully carburetor?

Re: At a loss. 1949 Ford flathead V8
 

https://redirect.viglink.com/?format...72_p_2500.html

Copy of a Holley 94 carb I believe

Re: At a loss. 1949 Ford flathead V8
 

where are you located, maybe someone close can lend you a good running carb that aftermarket carb could be your problem.

kurt

Re: At a loss. 1949 Ford flathead V8
 

I will try that. Thank you!

Re: At a loss. 1949 Ford flathead V8
 

Blue Ridge, GA

Re: At a loss. 1949 Ford flathead V8
 

Where do you have the distributor vacuum hooked to ?

Re: At a loss. 1949 Ford flathead V8
 

Since you bought it with the problem and then put the new carb on, it's not the carb. You've already ruled out bad gas. I think it is electrical.

Re: At a loss. 1949 Ford flathead V8
 

To a port in the rear of the carb.

Re: At a loss. 1949 Ford flathead V8
 

I have yet to check the vacuum advance with the timing light. I will do that tomorrow.

Re: At a loss. 1949 Ford flathead V8
 

Are there multiple ports ? The distributor uses a unique vacuum source . If you’re not familiar with the load-matic ( ?) distributor, read up on it . But you did mention that it was running this way before the carb , so it may eliminate this venturi vacuum needed for the distributor to work .

Re: At a loss. 1949 Ford flathead V8
 

No, there is just one port. The new carb is identical to the replaced one the owner used for years. I used the identical port in the new carb.

Re: At a loss. 1949 Ford flathead V8
 

Take all the plugs out and do a compression test on all cylinders at wide open throttle with someone helping you. Maybe there are some intake valves that are not opening. If it were mine and I eliminated all electrical problems including the coil, I would take the intake off and check the valve adjustment.
Also, beautiful show cars often have poor grounds. Is the coil wire giving you a bright blue spark about 1/2 inch?

Re: At a loss. 1949 Ford flathead V8
 

Coil is next replacement. Thank you for your suggestion.

Re: At a loss. 1949 Ford flathead V8
 

Along with the coil you might try a hot wire direct from the battery to the coil. There is the chance of a bad ignition switch. I was stymied by one in the past with the same symptoms. Tim

Re: At a loss. 1949 Ford flathead V8
 

I will definately try both suggestions above. Thank you for your response.