horrably running flathead

Hi there. i'm new to the boards(my intro is in the "new to the boards section") and i have a question about a flathead. i've got an 8ba motor with dual 94's(via a "y" adaptor) and its running horrably. i think its getting too much gas, but i'm not sure. it will start after a few tries, and will sound like its only running on 5 or 6 cylinders. it will rev up(after a little coaxing with the gas) and will seem to clear its self out, then when it comes back down(below 1500 rpm) it will start running on 5 or 6 again. when i try to let it idle it just sputters and dies. i have the stock distributor(rebuilt) and the 94's are running non-progressive. i've read most of the articles on tuning flatheads here, but i cant even get my motor to the point of fine tuning it. this is only my second motor so i am still really unsure on what i should do. any help would be great!
Thanks,
david

 

Your dumping alot of fuel if your engine is stock. Have you synchronized your carbs? How about va***m leak? How did it run before changing to 2 carbs?

 

Stock dizzy? Load-a-matic. How do you plumb the vacuum to the cannister? The stock dizzy uses ported vacuum,if you use manifold vacuum, it won't work like it should. The vac. signal from one carb,out of two won't work either. You could try lighter springs on the advance plate,play with the eccentric posts(with a distributor machine). My suggestion is to use a dizzy, with centrifical advance. In the meantime,I'm afraid you will have to revert back to a single 94,so you can get it across town,without flooding, sputtering,or dying. Also make sure you don't have any vacuum leaks,floats adjusted right,etc. Good luck, my friend. Sparky

 

Hey Mate,

What sort of power valves are you running in the 94's? stock? If so that is part of your problem. Can be a little work to set up 94's and in my opinion your pushing **** up hill with the stock dizzy. Even without the duals, replacing the stock dizzy gave a m***ive increase in usuability and performance to my 8BA.

Danny

 

The vacuum signal from one carb works just fine if you understand the 94 and Lodomatic. It is not ideal but workable until a better ignition is used. The other carb venturi port can either be plugged or run to a vacuum gauge inside the car. The vacuum gauge can be used to select the proper Power Valve since it must be done under load (as in driving).

No sense in wasting money recurving that dizzy either. Instead turn the spring posts with a pair of pliers. They are on an eccentric and you can pick up a little improvement. This is called tuning by ear, exactly what rodders did for decades.

That Y adapter was a piece of junk in the 50's when Almquist and other junk dealers conned kids into buying them cuz they couldnt afford a real intake. It dumps way too much fuel to the inner cylinders. Save your money and buy a real dual intake.

 

Dave- Sorry if some of this is a little basic, but better to be safe than sorry...

Here's some other things to consider- as the above posts cover the distributor situation. I agree that your two 94's are probably dumping way too much fuel, in other words the mixture is probably way too rich. I have 97's and a 48, so I'm not that familiar with 94's- but the guys who are might be able to recommend a jet size that would of course be smaller than stock. You might want to post your engine's displacement and other mods like cam, headers, etc. Also if you drive at higher al***udes.

Other simple and cheap things to check out are the plugs, battery charge/condition, coil grounding, and plug wire condition. If you are using aftermarket heads like Edelbrocks or Offies, a common mistake is to use the standard reach plug. I know from experience that stock plugs are too short for Offy heads. Your overly rich carbs (***uming that's the case) have probably fouled the plugs. Pull the plugs and let us know if they are covered in fuzzy black soot. If so, you may be able to run temporarily on fresh plugs in case you get stuck somewhere. I wouldn't recommend a hotter spark plug until you address the carbs and or dizzy.

I like progressive linked carbs. I'm running a 3x2 that responds as crisply as a mechanical secondary 4bbl I had on an old 289- maybe better. The outer two carbs on my flattie start coming in approx at 1/3 throttle and of course all three are exactly wide open at full throttle. It's not that hard to set up and IMO easier to run than trying to balance out direct linked carbs. Plus, 3 carbs are probably more show than go on most flatheads.

Good luck! This board seems to be a pretty cool place to find answers, hope you are able to make progress. Sorry for the long post Guys...

 

more info on the motor... its got a merc crank, and a warm cam. exhaust is let out by dragster style headers(name?)


well, i may have found one of the reasons it was running horrably....i did another compression test, and the number 6 cylinder was reading 0. i pulled the head and intake and found the intake vlave not seating correctly. i cleaned it out(seat and valve), and now its running about 100 psi. i also went and found the smallest jets (42's) and ordered 2 pairs. i'll install them and go through thye carbs once more and try to fiddle with the dizzy to get it right(or driveable for now, i dont have the money for a new electronic one). tomorrow i'll fire it again and try to tune it more. if i cant get it running right, i may block off one carb and run just the main one. i really like the look of that stupid "y" adapter...so i'm gunna try to keep it. if it wont work...i'll just toss it and run the single till i have the $$ for a real manifold.

thanks for all the help guys!
dave

 

At the minimum to get it running I'd change to .048 jets and make sure your powervalves are good ( I put new, stock 750 pv's in both of mine and junked the plugs I was talked into starting with) (some guys go with pv in one carb and plug in the other) and bolt on a capacitive discharge box to fire them black plugs your gonna have, a cd box will fire about anything. Any way you look at it, duals on a stocker is just too much fuel but this might get it
runnin.
Hope this helps till you can get some more speed equipment,

 

Have you considered running the linkage progressively? On a typical 2x2 intake, most folks frown on that from a fuel distribution standpoint, but since yours are on a "Y" adapter, there are no distibution problems other than the original intake. Might make things better to run progressive - just like a normal 4-bbl or the 2x2-to-4bbl adapters....

There really is no reason you have to run the carbs direct...

 

POINTS AND CONDENSOR.

If its carb which its not you would have black plugs, black smoke out the back and a strong smell of fuel. Have you got any of these?

 

I would say hold everything spend 5 minutes with a 1/2" wrench to put a single carb back on in place of the silly adapter, hook up distributor correctly, and get a shop manual..get the thing running right on the single before you start trying to soupitup! It sounds to me like you have jumped in without the basis of a good running engine, and you have so many potential carb and ignition problems, with a likelihood that several are occuring at once, you are unlikely to ever get it sorted!
Once it is running properly with one carb, swap carbs and sort out the second as a single. THEN start messing with ONE thing at a time--you'll now be able to spot single problems and kill them one by one.
Save the bread on 42 jets--I doubt car will be capable of moving with those.
Your carb problems with the Y are gonna involve distribution, power valve, and maybe idle-off idle circuits, but stock jets are going to be pretty close to right. 42's will flow just enough fuel for an occasional backfire as you try to get the thing out of the garage.

 

This my sound stupid, but if you like the look of the Y adaptor but need to drop back to one carb. Why not just install a plate under one carb, and block fuel flow to it. That way your only using one carb, but will still have the look you like.

Rod