1949 flathead v8 no acceleration

F

frmhrt

Member
New question from newbie. First of all, thanks to all replies to my previous questions, but also for this forum which is extremely interesting and informative.
Question: Newly rebuilt flathead v8 1949 289. Starts great. Idles smoothly at approx. 540 rpm. Sluggish acceleration and can't get rpms over 2000 and acceleration is slow with flooring, just tops out at about 2000 when floored. Accelerator pump kicks out good stream from both orifices. Timing seems advanced significantly at idle but it runs nice at idle. Carb. Vacuum at idle= zero. With acceleration to highest rpm approx. 2000, carb vacuum actually increases 1-2 psi.
Taking carb to rebuilder tomorrow to bench test. What should I be looking for/asking? Seems like something in carb is blocked? Fuel or vacuum advance? Is this the 90% of fuel problems due to spark problems? Am I on the right track?
Any suggestions appreciated.
Thx
alan
 
Make sure timing is set correctly and check vacuum with a vacuum gauge. If it isn't 15"+ I would suspect cam timing. Were the dots lined up on the cam gear and crank gear?
 
I should have said "check manifold vacuum". I took it that he was checking at the venturi port for the distributor advance.

And recheck the plug wires and firing order for proper location in the cap.
 
I think we need more information. He says a 289 flathead. If that's not a typo, there may be other things done to the engine. I would at least want to verify the actual size of the engine and if any other mods (carburetion and ignition) have been made. Hell, it may even be a SBF from the information given.

More information on the engine please.
 
"Timing seems significantly advanced at idle" , Sounds like a loadamatic with its vacuum line connected to manifold vacuum. "vacuum at idle is zero" and vacuum reading goes up. Where are you connecting the vacuum gauge? Sounds like a vacuum gauge connected to the ignition port on the back of the 8BA type carb. Could be vacuum lines switched? Wipers connected to carb and ignition connected to manifold, for instance? Should be ignition connected to back of carb.
Just a guess from the original post.
Frmhrt, could you confirm your connections and is the engine all factory stock including its carb and ignition please?
Martin.
 
Venturi vacuum like on a stock 8BA should be about 0 at idle and then rise with acceleration.
Measuring manifold vaccum from the fitting for vacuumwipers will tell you what´s going on with ignition/valves.
If you have a strong spark even a timing way off should let you rev the engine up...
How about if you use the choke...any difference ?
 
Great advice here, I wouldn't start blaming the carb. just yet.
Sounds like timing. I experienced similar symptoms years ago when I started my truck for the first time. Engine would idle, slow acceleration was "kinda" OK, would not rev up without studder, belch and fart.
Opened up the front and found the crank and cam gears were 3 nubs off. I messed up when I had installed the new aluminum cam gear.
Another more common oops is plug numbering. Right side from drivers seat are front to rear 1,2,3,4,, left side are again front to rear, 5,6,7,8,.
Then I know a guy (oops) who had his dist 180 degrees out of time...Don't ask ;-(
Enjoy the adventure, Chap
 
It's best to lead your query with the type of vehicle and whether it is stock or modified. If modified then the type of carburetor and ignition is important to know for troubleshooting.

If it's a truck with a big old 11-inch Long type clutch then it makes a difference on engine rpm response time. Trucks are slower to respond than say a car engine with a 9.5-inch Long type clutch.

8BA family engines all had as OEM a Load-O-Matic vacuum only controlled distributor for spark advance & retard with a corresponding carburetor made to function that distributor. Changes to the carburetor can have a detrimental affect on engine function. If the vacuum can is leaky then the advance won't work.
 
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Have been out of town, now back and following your advice. sorry for lack of responses to all of your helpful information. I will address your questions/suggestions, and give you current status.
1. Yes, mis typed. It is 239 Cubic inches, stock 8ba and holley 94 carb, loadmaster dist. – 1949 F5 Ford truck -all stock including the 11 inch clutch.
2. Was checking Venturi vacuum but had leak in test gear. Will try tomorrow after #4 adjusted and see if Venturi is present to create vacuum advance. See #4 below for “Duh” moment.
3. Carb rebuilder (local Sac. Carburetor Factory) checked it out no chg. (4 yr. after rebuild.) found it all ok and clean.
4. Timing was actually retarded about 20 degrees. It’s a wonder it started and ran at all. Wondered why it was getting so hot. Duh. Finally pulled Dizzy cap and figured out that distributor “sprocket” was one tooth off. Pulled shaft up, rotated clockwise until it fell into next slot and voila, the rotor lined up with the #1 wire at TDC mark (2 degrees before TDC). Vroom, vroom.
Thanks for all the suggestions and help. You pros are uncanny in being right on the various possibilities and help us rookies to hone through the list.
af
 
Thanks for getting back to us with solutions. Always good to hear about solutions and steps taken to solving the problems. Have fun. Mike
 
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