We are building a truck, the engine is newly rebuilt, it has a Scat crank (stock), a Z head, and a .280 cam, high volume intake manifold. I have Holley NH, Kingston L-4, the NH would be better with the high volume intake, but what would be best? Stromberg OF or some other?. Thanks
I would go with ether of the carbs you have for now. Then think about an OF Stromberg, Schebler or one of the straight through like NH, Simmons or even early Marvel. Off the cuff, I would think the Kingston with it's flapper might give a richer starting mix but then I like the L4's. Then again the L4 may be too restrictive at the top end. Try them both.
Don't use the L4. It ranks near the bottom for flow characteristics (< 20 CFM). It's a common mistake to expect bolt-on accessories to actually improve an engine. What is the flow of your block? No mater what you bolt on, flow won't exceed what the block and valves allow. With a 280 cam, I suspect around 45-46 CFM on the top end.
Ken, How do you measure that Flow?
I like my OF carb and hear only good things about them.
It is a high flow system, it also has a dual exhaust manifold,I know the L-4 is low flow.
What would be the best carb all around for this ?
There is no better all-around carb than an OF Stromberg. Anybody who thinks a good carburetor doesn't improve how a Ford runs has never used one.
Stromberg sold over 500,000 OF's from 1922 to 1926 at $15.75 each. There was, and is, a reason. Or a bunch of reasons.
I think the OF is a great carb but I don't know the flow specs for them. Perhaps Stan knows. You can over-carb an engine as easily as under-carb. A matched "system" will run better than any bolt-on mix of parts. That's all I'm saying.
The volume of sales can be a poor indicator of actual value and can show anything you want. There were over 1,500,000 Pet Rocks sold in six months. That doesn't make them the best rock.
Ken, $15.75 in 1922 dollars equals $222.59 in 2014 dollars. Id say that speaks alot for just how good these carbs were for people to plunk down that much dough in 1922/26.
Yep. It says Stromberg had a good marketing program.
Show me the specs.
Rick -- As Mark G. said, one of the straight-through carbs probably would serve well with your other equipment. The Stromberg OF is one, with rave reviews from those who use them. Less pricey and relatively easy to find are the NH and Simmons/Wizard brands. I like the Simmons (also sold through Western Auto as a "Wizard") for its simplicity and overall great performance. It's what is on my driver T.
There is a lot more to a carburetor than what it flows. The Stromberg OF was the first carburetor engineered and manufactured for the Ford engine that had three distinct operating circuits. It has a main jet circuit that feeds fuel to the engine at all speeds above idle. Stromberg's patented self compensating main jet, removable from the carburetor for service, changed the ration of gasoline to air depending on speed and load conditions. Stromberg vigorously defended this patent in court against many other carburetor manufacturers. It was upheld by the court several times. The second circuit is a true idle circuit that feeds fuel to the engine ahead of the throttle plate when the throttle plate is nearly closed as it is at idle speeds. This circuit is fed independently of the high speed circuit and is fed from the main fuel supply; operating at its setting regardless of the high speed adjustment. This was a first for Ford carburetors. The third circuit is an economizer circuit which mechanically opens an air bleed into the main jet to lean the mixture at times of low fuel demand by the engine, increasing fuel economy, reducing plug fouling and internal carbon deposits in the engine. This patent was also vigorously defended by Stromberg. Disregarding advertising hype, fuel economy is reported by users to be 20% above the stock Ford carburetor of any type. The OF also included when new a device called a hot spot which was a system to draw heat from the exhaust manifold, pipe it to a muff on the intake manifold, warming the manifold ahead of the attachment point of the carburetor to the manifold to a heat that would enhance the vaporization of the poor fuels of the day. With today's fuel's this attachment is seldom used.
An additional feature of the OF was the small venturi using a Stromberg design in which the main fuel orifice - feeding directly from the compensating main jet - enters the incoming air stream at the smallest point of the venturi, which has the highest airflow speed of any point in the intake system. This enhances the atomization of the fuel, breaking it into smaller droplets and better preparing it for gasification in the intake manifold. Raw gasoline will not burn, it must be a vapor. It has to gassify or evaporate to explode in the cylinder. The smaller the droplets and the warmer the fuel, the quicker it will gassify. This also helped the OF produce better fuel economy than other carburetors.
Compared to other accessory carburetors of the day.
Is it the simplest? No
Was it the cheapest? No
Is it the fastest? No
Is it the highest possible economy? Probably not.
Does it produce the most power? No
It it the most readily available today? No
Is it the best all around carburetor for Fords? In most people's opinion. Yes
Stromberg was the largest carburetor manufacturing company in the world at the time the OF was built, considering non-original equipment carburetors. They offered over 100 different carburetors for virtually every automobile built. Manufacturer after manufacturer advertised that their cars were equipped from the factory with Stromberg Carburetors, saving the cost of upgrading the carburetors after purchases. From 1919 to 1930 every Studebaker was factory equipped with a Stromberg. Peerless, Huppmobile,
Franklin, Graham, Nash, etc., etc. bragged that their cars were Stromberg equipped from the factory.
Are there better carburetors than Stromberg OF's for Model T Fords? There may be. I know that I have rebuilt hundreds of them and have only had two people who didn't think it made an improvement in how their Ford runs. Since I do virtually any brass carburetor I really don't care what I get to rebuild but I will say this, Stromberg is the best built of virtually any. Precise machining, quality in every part, parts made of brass instead of some cheap pot metal, etc.; they appear to me to have been built up to a quality and not down to a price.
The Stromberg OF was the smallest, cheapest carburetor made by a huge company that already had the engineering and technology proven in their larger and more expensive carbs. That technology and knowledge, manufacturing quality and reputation protection was transferred to the OF when it came on the market. There were good reasons they sold over half a million then and why they are still the most popular accessory carburetors for Model T Fords today.
ALL carburetion is a compromise.
I'm off to the shop, had a huge Buffalo/Longhorn auction in North Dakota day before yesterday, drove 750 miles home yesterday so I could go work on carbs today. You guys argue, I'll be the guy cranking out a couple OF's today. (if you want to see what Buffalo and Longhorns look like www.frontrangeauctions.com -- I'll post some pics of the auction on there later, too busy right now.)
In my tests, an OF flows about the same as a straight-through NH.
What max power RPM are you hoping to get? The high compression helps at all rpm. The other things help top end.
There is a lot more to carburetion than the amount of air it flows. If all you want is a carburetor that has maximum flow, why not use one with a venturi as big as the manifold?? Would that not flow more? All carburetors are compromises between starting, low speed and high speed performance, acceleration performance & economy. Try to start an engine using a carburetor with no venturi or a very large venturi and it will become obvious.
Do U happen to have a Stromberg OF that U would part with?? Maybe I could get one or two more HP. I'd use it on the 25 Fordor W/ an A crank, Z head, 280 cam, Drilled mains with an Oil Pump, a R-12 air Conditioner and an Alternator. Also a Ruckstell and a 3 speed aux transmission
I'll have to look. I have two that I need to finish and get in the mail soon. I have lots of bodies but running short on steel parts until I can get more laser cut. Having trouble finding someone who can do it for me. I could probably put another one or two together out of parts, then I am going to be stuck until I get steel parts back from wherever I find to get them done. I'll put your name on one, Hal. www.strombergof.com
Tests were made with different carbs, and this one showed the best bench flow was the OF. (top)
Another test with carbs.
The NH rates pretty well.
Hal, I have a beautiful OF that Stan restored. I only used it on one endurance so it is virtually new. I want to sell it, so PM me if you are interested. You can check out Stan's website for an idea of the cost. I will sell mine for a bit less than what I paid for it.
San Jose, CA
I just got my 'OF' back from Stan yesterday. It's almost too pretty to put on the car ... almost
Bob, I have to say thanks and I also have to say I wish I had taken a photo of that one before I started on it. I didn't take one after I got it done either but they all look about the same after restoration. That one was just especially nasty before.
Tom, what did you replace your OF with? I'm thinking it was a U & J or a Rayfield UF.
An OF is not the best carb for a speedster if you have been doing lots of things to the engine and are mostly concerned with going fast. There are lots of other options. Jon Allen put an OS-1 on his 14 and is putting an OX-2 Stromberg on his new speedster. The OE-1 and OS-2 are the most popular for flatheads, OS-2 and OE-2 for overheads, Zenith HP4S and HP5A are great side draft carbs. HP4S are made out of unobtanium and I don't think anybody rebuilds them but me. They are too fussy and over-jetted in stock condition, I make an adjustable main jet for them that really brings an engine to life because you can dial it in at speed instead of filling and drilling jets trying to get them to run right. I have the only HP4S I have seen for sale for a couple years restored and ready to go smoke up a speedster run or two or three. They were only used on a few cars in the mid-teens. I sold two that I had to a guy who is putting them on a Roof 16 Valve with a stroker Scat, big cam, etc. This is the 4th one I have ever seen in all the years I've been doing this. They look really cool, too. You can see my adjustable jet on the bottom of the carb in the first picture. I think this is actually a picture of the one that I sold but I have another one done that I did up for a show I went to when I put some fancy brass carbs on display.
I'm going to be doing a set of 4 Stromberg side drafts for a guy who is doing a twin engine hill climb car as soon as I get back from Christmas. They will make it zoom up the hills.
Bob, You are very right about how nice those carbs look after Stan does his Magic on them!
They run as nice or better than they look.
Thanks Stan for the work you do.