I have just picked up a 54 dodge C-1 pickup, It has the original flathead with Phillips performance exhaust manifolds, an Offenhauser intake, twin carter one barrels, and Phillips performance air breathers, the engine is fresh...here is my question, this thing runs like ****..fuel wise, ignition seems good points properly gapped, dwell looks good, timing is right on and holds steady as a rock, but this truck falls on its face at low rpm, Does anyone know where i can find information on setting up dual carbs? are they worth it?, I know they look cool, but if they wont ever work, id rather pull them off and run a single...any feedback or information on setting these things would be appreciated Thanks Al
Have you checked the timing? When I married Sweetie, she brought a cherry, 11,000 mile 53 Ford along with her. Great car, ran good, the six was a dog. Kinda strange considering dad had a 50 Ford six sedan and another that was a V8 sedan. His six ran great. A little digging showed that bother-in-law had done the last tune-up on the 53 and the timing was retarded quite a bit. Setting it correctly made for a great running little car. If the timing shows ok, put a vacuum gauge on it and if it shows low steady vacuum the cam timing may be off. A good running Mopar flat six should show 17-19" of vacuum. If it shows around 10-11" vacuum it may be a cam a tooth off.
That sounds like a vacuum leak, possibly around the intake manifold gaskets or carb gaskets. It could be a crack or missing piece of the manifold or carbs, too. Anyway, it's not the dual carb setup per se; if you get it set up correctly, it will run smoothly. ... On the other hand, if you decide to get rid of the performance parts, just let me know.
Thanks...should I be looking at pure manifold vacuum, or should i be looking at each carb individually, initial timing is set at TDC as per mopar spec, total timing is about 18 degrees, which is what it calls for, Maybe you can answer one more thing...should the vacuum advance be connected to manifold vacuum? or ported vacuum, as in above the carb ****erflies? do you happen to know...I have enclosed a picture of the intake setup
Not sure about Dodge, but similar applications with Chevy 6's call for taking the vacuum from the carb base and not the intake (that is for your vacuum wipers). I agree with previous comments. Vacuum leak should be your first check. Those B&B carbs may or may not want to operate well in tandem. There is a guy on here with the handle Carb King that would be the best authority on their performance in multiples. You need to invest in a unisync. It is used to balance the two carbs. Here is a source and a pic: http://1800vw.bizhosting.com/uni_sync.html
Did you shoot the timing with the vacuum line disconnected from the distributor? If you didn't you may be getting fooled with the total all-in timing. Vacuum levels should be sourced to manifold vacuum for checking.
set timing with vacuum disconnected, then checked total timing after reconnecting....I know it sounds like an advance problem....but the timing seems to check out fine
Does the motors manual you're getting the info from state that total timing is checked with vacuum advance connected? With the vacuum advance disconnected are you seeing mechanical advance? In other words, spin the engine up a bit and see where the advance goes. Stay out of the plane of the fan, a fan blade can kill or greatly injure. After you determine that the mechanical advance is working, connect the vacuum advance and see if you get some advance from it. I note your original comment says that the truck falls on its face on the low end. Big rear tires? High diff ratio? Does it pull hard once it's rolling? It could be possible you're used to a much higher horsepower vehicle and the truck is already doing about as well as it can and there's nothing wrong with it....
Ive had a few latheads...and ive got a 29 model a ....not much horsepower there no ..this thing is stumbling....put it to the floor..it will get through its stumble then pick up smoothly...i will check centrifugal advance tonight..you have a point if the weights are hanging...it sure feels fuel..but who knows...like i said id rather pull the duals and have a smooth running beast...im not really interested in spending a ton of cash on the flathead, the plan is drive it next summer as is while gathering parts, and make a small block mopar swap next year...but if this thing doesnt get to be a whole lot more fun, the swap could come sooner than later Thanks Al
Even if engine vacuum seems normal, it could be ****ing air around the manifold gaskets or through a loose fitting, resulting in an overly lean mixture at the engine. The traditional way to check is to spray the gasket areas with something like starter fluid and see if engine speed changes. That's fairly dangerous though, so be very careful if you try it. On small engines, like Harleys, you can test for manifold leaks safely using compressed air and a special plate over the carburetor opening. I've never tried it with a bigger engine; I'd probably just take the manifold off and look for defects.
Received your email with the thread URL. The reference below should help you with adjusting the dual carbs; but like others who have posted before me on this thread, I believe either timing or vacuum leak is the culprit. http://www.thecarburetorshop.com/Dual1barrelcarbs.htm Do not know if true with this engine; but have run into more than one occurance of a harmonic balancer that "slipped" thus changing the position of the timing mark. Really sounds like insufficient advance, but could obviously be other things. Jon.
It may be a stretch, but on the Carters I have for my Studebaker flat-head 6 with dual Edmunds manifold, they have a small holle in the base that draws vacuum below the ****erfly. The correct gasket has a slot cut to provide the vacuum. Are the gaskets correct or on right?
as only one of many guys who have run a simlilar setup- yeah- it can be a whole lot of fun. My experiences have led me to check the vacuum advance on every flathead Mopar I work on. I had several bad ones. After you make sure the timing and advance are working, mess with the carbs. What kind of linkage are you running? the balance bar setup that comes with an Offy intake is **** in my opinion. I had nothing but trouble. Couldn't keep it from slipping, couldn't get the carbs adjusted. I fabbed a linkage that put the carbs independently adjustable- TOTALLY worth the time. On second thought- that stuff is JUNK!!! pull it off, send it to me, and I'll send you back small block Mopar stuff!
ok...so i have about 11 inches of vaccuum....peaks at about 15 at about 1200 rpm...then falls off......does this sound like valve timing.... this engine is supposed to be brand new..and everything else this guy has told me has been true.however compression is only about 95lbs on all cylinders...goes up to about 125 with a squirt of oil...could the rings not be seated yet or have i been screwed...will cam timing affect compression...does anyone know..any opinions would be appreciated thanks Al
screw it...i bought a 360, anybody interested in buying this flathead setup? anybody give me an idea of what its worth?
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