MTFCA Forum

I am getting a speedster back on the road. We went with the dual exhaust. I'm looking for a carb that is more period correct.
Currently I have the lawn mower carb WILBRO. But it deserves something better.
The dual exhaust manifold gets in the way of the choke/mixture rod.
Now I am looking for a carb that is pretty close to period correct with the fuel mixture set.
Or I can use some idea on a Model T carb to prevent the mixture from changing through vibrations.
Please note that the pocketbook is limited.

You can stay will any T carb, like the later Holley NH, easy to put into tip top shape. Or go for the Holley NH early one, '19-'20 with the 'straight thru' design. Note the chart with that one, flows best.


And....all these T carbs can be made to 'a fix mixture set'.......just tighten down completely on the lock screw, no way the needle valve can migrate!

You can use a T carb, specifically a NH or a G will fill the bill IF/WHEN adjusted correctly.(not including wide elevation swings)
{Other carbs may respond the same, but, my experience is with the NH & G.}

The float level must be set for hi speed & idle functions.
Run @ hi speed & tune the mixture for optimal performance. Stop & check idle function. If enriching the mixture to get the optimal idle setting, the float level is to low. Conversely, if the idle is too rich, the fuel lever is too high. Readjust the float until the motor is happy @ hi speed & idle. Done. You dont need to fiddle with the mixture any more. This procedure fine tunes a NH.
On the G carb, the exact correct fuel level is set by looking into the jet bowl for the correct fuel level with the needle body top off.
A well tuned carb dosent need constant fiddling with.(Including starting, thats what the choke is for.)

Setting the mixture whall running for your carb tuning can be done with a long remote rod. I have dual NH's on my 27. I have 2 forked rods to run thru the windshield for carb tuning. Never had to touch the mixture adjustments since the first setup.

Honestly, without knowing what modifications have been done to the engine it is really impossible to give a decent suggestion.

Dan; If you look close, the top carb on your CFM chart is a Stromberg OF. It's also the only one on the chart that is truly a "set and forget" as every Holley or Kingston T carb is a kinda poor compromise for fine tuning for all speed and load conditions with just one setting. There are others that would be "period correct" and flow even better than the OF and they are the Stromberg RF, the Rayfield UF, the Wheeler Schebler FAX8 and best of all the U&J . I have nothing against running a stock factory carb, but if one wants efficiency (a much better air/fuel mix for all conditions) a smoother running motor, less carbon build-up, and better fuel mileage with more power, any of the mentioned carbs will fit the bill. The late Stan Howe posted tons of information/comments on these carbs and he truly knew what he was talking about. Funny, but I must have talked to two dozen T guys at Hershey about carbs and all but one was very content with their NH and most had never even heard of the carbs I mentioned.

"all but one was very content with their NH" There are a lot of people that have never gone past the carb on their cars, so are content with what is on it now, not knowing any difference when all they are doing is putting around the hood or going for ice cream.

Mark Gregush wrote: ↑

Fri Oct 21, 2022 2:46 pm

"all but one was very content with their NH" There are a lot of people that have never gone past the carb on their cars, so are content with what is on it now, not knowing any difference when all they are doing is putting around the hood or going for ice cream.

A NH is capable of 55 + on a full body, stock T. See Montana 500 race specs. They AVERAGE 55-58 in a run. (Thats average over 500 miles, including start stop speeds & city speed limits.) Flat & down hill 60-70+.

My observation here is many wouldnt think of going over 45 unless out of control down hill. They couldnt due to under par chassis, engines & ignition systems.
a NH is clearly a capable carb. for more than ice cream runs.

I dont have the experience, first hand with Strombergs to make claims of their adequacy @ higher speeds, but, I do know people that are very happy with the performance characteristics thru the speed range to 55-60.

It sound as if Stromberg, Rayfield, and Zenith, U&J and others, made hundreds of thousands of accessory carburetors for no reason at all, given that everyone was already tooling around at 55 and 60 on their NH's anyway. (!?)

And yet, anyone who has ever installed one of these accessory carbs and didn't say "WOW" afterwards, has other problems...

My first car was a '56 VW bug. It would hit 50MPH with no problem...in about 2 miles
My best friend had a Camaro and it would hit 50MPH by the other side of the intersection...
Could I claim that both cars could hit 50MPH so there was no difference in them performance-wise?

MT500 folks mandate NH's to LIMIT the speed, not because they are such great carburetors. For a normal car, they are adequate, but a carburetor upgrade will nearly always result in a performance upgrade on most any car.

If you're happy with a puddle carb, then the NH is for you. If you are looking for something a little more sophisticated with more torque, lug-free shifting, better economy, and increased power for hills, then an accessory carb can do all of these things. Will they make the car go faster over all? That's up to your engine and your nerves, but you will certainly have more power available at lower speeds, and a smoother performing car nearly for certain.

The next time you hit a hill, open the throttle and the only thing that happens is the air-rush sound gets louder on your NH, and another guy easily cruises past you with no drama or extra noise, he is likely running a Stromberg OF or similar.

Yep, Scott, you pretty much nailed it. The fact is that Ford made over 15,000,000 cars, all equipped with Kingston or Holley carbs and every last one ran just fine for thousands and thousands of miles. No one complained about poor performance, fouled spark plugs, or the Ford recommendation that the owner remove the cylinder head every 400 miles to clean out the carbon as there was very little to compare to, and besides their Model T ran just the same as everyone elses. My first six model T's all had Holley carbs and I was quite satisfied at the time. They did the job and "put the world on wheels" and they were CHEAP, I'm guessing maybe $1.50 each cost to Ford. Somewhere along the line the aftermarket people realized they could provide a much more efficient device that maybe only a fraction of T owners might appreciate, but that would still be a big market. The four aftermarket offerings that I'm familiar with all are a major improvement over any stock T carb. Rather that a wick in a puddle of gas, they have separate circuits to provide a much more controlled and precise mixture for all speeds and load requirements. The result is a cleaner and smoother running engine, better fuel economy, more power, and the absence of the in-car adjustment need, (and they all go on the intake with bolts into a threaded base, not the nut & bolt PIA system) . The only drawback back in the day was price ($15-$25.00 each). I'm betting that maybe only 0.01% of T owners tried these carbs but I'll bet my life that every one that did said "wow", and never put the NH or Kingston back on their car. I have a T buddy North of Toronto that has owned well over 100 Model T's and as of last year had never even heard of a Stromberg OF and when I offered him one to try, he declined, and that's just fine too. "To each his own"

Bruce

many if not most Forum posters believe that they represent the majority of "T" owners. In looking at the numbers, though, nothing could be further from the truth. The vast majority of T owners do not belong to either national club and of the scant percentage that do (or do not) they do not avail themselves to this Forum. What many or most of us have been exposed to regarding these carbs, either intellectually or in actuality, via the Forum, I suspect that a full 99% (like your friend) do not have the breadth of experience to recognize their usefulness and appeal...having owned 100 Model T's notwithstanding!

Scott. Sadly I have to agree. Many of the T guys I talked to at Hershey had never heard of this forum as well. Hard to believe as they're missing out on lots of valuable information, pictures, history, personal opinions, knowledge and great general comments that are abundant on this very special site.

My first car was a '56 VW bug. It would hit 50MPH with no problem...in about 2 miles
LOL my 56 VW lost speed going downhill off Mt Hood and I understand the other part.

I never change the mixture setting in any of my cars, unless I'm at 10,000 feet.

I adjust the NH mixture setting as needed to get the best results under varying conditions. It will start and run OK at one setting, but fine adjustments, performed as needed, if needed, yield the best results. Ford seemed to agree, if you can believe what they wrote on the subject. The same is true for the timing. It's very laborious to reach over and tweak the mixture knob from time to time, and adjusting to the ignition timing to suit speed and load is exhausting, but I persevere, nonetheless. Of course, I make sure to have at least some Marvel Mystery Oil in the gas tank. For some reason, I find these on-the-road adjustments to be un-necessary on modern vehicles equipped with automatic ignition systems and carburetors. Perhaps they have a mind of their own.