GRAVITY FED DUAL 97s ON MODEL A BANGER? Well I have lost my pass word to the Old Ford Barn and it does not want to email any help so hopefully someone on here will have some thoughts. I have 1930 Model "A" Banger Truck. It has a rebuilt motor and was running good on the original stuff. This weekend we put a set of headers on it and vintage Riley Dual Carb set up with Stromberg 97s. Much to our delight it fired the first time. It was running a little rough with a few backfires put I expected that since the carbs had not been adjusted etc. However, nothing we did really made any difference. We even double checked the timing and it is dead on. It seams like it is not getting enough fuel. It will only run if the back carb is basically full choked or if you put your hand 60% or more over the front carb with the rear one half choked. With the rear carb fully choked, it smooths out and idles pretty good. We are gravity feeding these two carbs. I have heard some guys say it won't work and must have a pump and others say they are running two 97 gravity fed just fine. I am going to pull it back down tomorrow and make sure the jets are clear etc. I know the Stromberg can take a max of 2.5 pounds of pressure, but I'm not sure how much pressure gravity fed provides, let alone split...etc. Thoughts anyone....anyone.
youre gonna need a fuel pump. I tried to run a single 94 on a banger once, worked alright up to about 2000 rpm then ran out of fuel, and was worse the lower the fual level in the tank. the little square 'facet' electric pumps are a simple solution. if you get some new grose jet Stromberg twin ball inlet valves on the carbs (from stromberg97.com ), you wont even need a regulator, as these can handle higher pressure than the old needle and seats.
If you look at the height difference between the lowest fuel level and the float level it would be a few of inches Max , really not enough height to get any sort of fuel weight to get flow sufficient. Yup , keep it looking old but hide an electric pump.
That is a cool looking setup!! Don't know anything about this but I've seen old hand pumps I believe to pressurize the gas tank? Those little electric pumps work great but are a bit noisy(clicking) Pete
what about a decent sized vacuum pump like we use on the race Kohler engines etc, maybe one for each carb. quiet and small, just needs a vacuum line.
I'm running the same intake with dual 97's. While doing the initial tuning (wide band O2 sensor) of this setup, I found that I was running out of fuel at anything over 2000 rpm. Also seemed that the idle was inconsistent. Playing with jets and power valves constantly. Went to an in line pump(from Macs), a low pressure Holley regulator (set at 2 lbs), end of problems. Car (31 Tudor) idles at 500, good throttle response, excellent top end. The biggest issue I had was the timing advance, spent days working that out for my combination. Ken
I just ordered a low volume pump and regulator so hopefully that will get the carbs up and running. I have another issue though but not sure if it is related. Cylinders one and two are firing but ad nothing to the engine. It is running on the back two cylinders only. The timing has been checked several times. The valves are all working both intake and exhaust. There is good compression in both cylinders. There is fire to the plugs and the plugs are firing. My opinion, since the headers are all near the same the temperature those cylinders are firing but after the piston is headed back down to the point the ignition just burns the fuel with no real push to the piston. Any thoughts on this issue and is it related to the carbs?
After you install the fuel pump, regulator and change the jets and powervalves to .043's and 70's respectively, be sure to turn your scoops around to facing rear. Strombergs work best when gathering air from a non-turbulent, non-restrictive, dead-air space; also prevents siphoning fuel at speeds over 150 mph...
Followup to my initial reply: I'm running a Mallory dizzy with the E-spark conversion. Everything is 12v. Timing I ended up with 16* initial, 26* total @2500. Set up on a Sun machine. I have several of the dizzys, setup several different curves, went out and used the***** dyno to tune. My compression is 125# @ 8:1 Sounds like you might have some leaking intake seats, compression and leakdown are in order. The other vacuum leak point is the header flange to block, use the one piece gasket, trim the two piece (green) intake gaskets to seal the manifold to the header flange. I also used red RTV on these gaskets. I ended up with 43 jets and 71 pv, plus setup with progressive linkage, front is primary, rear comes in at 75% throttle. Ken
Thanks Uncle Max, good advice. I am also going to have to figure out how to strap the hood down for 150 mph....LOL! Thanks though, I will flip the scoops and I have the jets and power valves on the way as well.
Thanks, good call. We were also thinking about the intake mount area. I will snag some red RTV. We are going to pull it all back down after an indoor car show this weekend. We have a lot of work to do but hope to have it running by Spring...Thanks for all your help and advise.
Well just a quick update. We installed a 6 volt, positive ground, Carter Fuel Pump on the Model "A" this weekend along with an inline Holly fuel pressure control unit. We set the pressure at 2 lbs. to start with and it fired right up. Thanks for the all help, especially Uncle Mac. Note we did swap out the jets and powervalves as you suggested. We even turned the scoops around (though 150 mph is quite out of the question - LOL!). THANKS AGAIN!
Damn, that's a good lookin' truck. Dig the banger mucho !!! Wires too.....perfect rubber stance....sure it could be lower....but I like it as is.
keep a eye on the holly and moroso and other chrome inline regulators, i have had 3 go bad and leak like a sieve, fortunatly they were on cars w/out hoods and i saw they were leaking. a friend also had same problem. made in china...
Is it one of those little square ones from Speedway under the guage? Posted using the Full Custom H.A.M.B. App!
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