MTFCA Forum

So Iam wondering if anyone that has tried a model A carb and manifold set up? I was thinking about this option and wanted to see if there was any draw backs to it. Iam not worried about being a purist so I’d appreciate positive feedback
This is the set up for carb and intake I was considering. Reading a little bit the T and A are interchangeable??.

Bryant wrote: ↑

Wed Nov 24, 2021 2:32 pm

So Iam wondering if anyone that has tried a model A carb and manifold set up? I was thinking about this option and wanted to see if there was any draw backs to it. Iam not worried about being a purist so I’d appreciate positive feedback
This is the set up for carb and intake I was considering. Reading a little bit the T and A are interchangeable??.7239C0A7-D79F-4AF6-9E18-E299B3DA4B19.jpeg

Ideally you add an extension to lower carb to not need a fuel pump. Make it at least 1" lower than a stock carb. (n/a 26-7)
Use an A exh manifold. Can use a C manifold, but A gets the pipe away from everything. No need for header plate. Outer stud holes need to be widened. Its a bolt on. Works very well.

There are plenty of period/accessory carbs which will make a stock T run MUCH better than the standard carbs which came with the car.

The best benefit from that setup will be if you have done some mods to compression/head, cam, valves or some combination thereof.

Scott_Conger wrote: ↑

Wed Nov 24, 2021 2:59 pm

There are plenty of period/accessory carbs which will make a stock T run MUCH better than the standard carbs which came with the car.

The best benefit from that setup will be if you have done some mods to compression/head, cam, valves or some combination thereof.

I really like the brass stromberg carbs. I was attracted to the zenith because of all the classic tractors I’ve played with. Kinda reminds me of there set up. I guess the rest is price/availability.
I have a fresh rebuilt block that Iam considering using a z head on. I like to ponder options well in advanced so if you had to choose a carb that was parts available/reasonably priced/measurable performance and period what would it be?

John,I was wondering about exhaust manifolds. C manifold? Firewall clearance issues? The car is a 26 so gravity fuel should be ok?

Bryant wrote: ↑

Wed Nov 24, 2021 3:56 pm

John,I was wondering about exhaust manifolds. C manifold? Firewall clearance issues? The car is a 26 so gravity fuel should be ok?

With the A manifold, the pipe comes down & forward a little, then around under crankcase. The whole pipe can be run lower & still not seen. Out of the way with no extra heat. I found an adjustable main jet for that carb. Runs real well. Of course, it was to wake up & work in conjunction with a high compression head, 5/8 valves, & hot cam.
I have the C on a 23 touring. Took a lot or finagling to get the pipe over the HH. I believe the 26-7 floor boards are lower. I wouldnt go that way again.

Bryant

regarding accessory carbs, there are none available with off the shelf parts availability, but there are folks who can manufacture parts as-needed. There are plenty out there that are restored and have been put on the shelf due to the owner seeking "better". "Better" is subjective...as in more power? more speed? more economy? more reliability?

• Miller Master and Winfield are considered the "ultimate" performance carb, but not easy to keep in tune and hard on fuel. Expensive and Rare.
  
  U&J is considered "nearly ultimate" with benefit of being pretty much trouble-free but not particularly easy on fuel. Uncommon and a little rare, not terribly expensive but not cheap either.
  
  Rayfield UF (uncommon but not rare), and Zenith S4BF are considered a hot carb with OK fuel mileage
  
  Stromberg OF gives more power, more speed, more economy than stock carbs and maintains its adjustment. Lots of Stan Howe and other's rebuilds available. Considered best all-round carb by many.

there are lots of others (some say over 200 others!) but many require custom manifold setups such as Stromberg OS-1 and others

Any of these carbs look great on the car, perform far in excess of any stock carb and are correct for the era...

Since I have neither owned nor run every one of the above carbs, opinions above are partially my experience and other's opinions in whom I trust.

I am in the opposite camp. I have not experimented with all these other options. Back some 40 years ago, I wanted a better breathing motor. (more speed). It was common knowledge, that an A ran better on a T & a C(carb) ran better on an A. Era, aftermarket wasnt as important as cheap speed.

I do know a couple guys running Stromberg OF 's. The run very well & are happy with the performance. If I had one, I probably would have used in on my 14. Since I had the A, I adapted it & lowered it & tuned it. It still runs great.

Keep in mind that the rebuild parts for an A have issues & original parts are preferred.

Scott; You pretty much nailed it in your carb performance rating except for missing the Wheeler-Schebler FAX8 which I would rate ahead of the Strombergs and the Stromberg RF that I would put slightly ahead of the OF. With the exception of the first one on your list , I've restored and tried them all and am keeping a U&J and RF for my own two cars although I may be sorry for letting the Rayfield go.. Actually the roadster I have now came with a butchered Model A manifold and carb and although it ran OK, I couldn't wait to get it off and replace it with any of the great period correct carbs you mentioned. To me, a Model A set-up just looks wrong on a T and makes me think that back in the day, if you could afford to modify you T with A parts, you would be better off just buying an A.

I like the period looking ones. The brass is great! I like the model A one. to me it looks fine. Just a little plain and simple. Seems very available. But when the hoods down it’s the model T I like. If you have any pictures of these carbs I would love to see them.

Bruce

you're right, I did miss the Wheeler-Schebler...I even have on sitting on my shelf waiting for some love!

That Rayfield UF you sold was a really nice looking original carb and I am kicking myself for not jumping on it.

Yes, Scott, it was close to the U&J ,(even nicer idle but not quite the top end)and was a direct replacement on the existing manifold....and it was NOS. I still have one really nice Wheeler-Schebler with the correct heat stove. On another topic, are you still making pieces for the OF?

I make them when I need them. Some parts I'm sold out of...some in stock.

I found a Rayfield in virtually the same NOS state as yours on eBay 6 months ago. Never a drop of fuel in it, but the steel parts suffered from 80 years of damp-ish dry storage just as you had described yours. I cannot bring myself to do anything to it other than clean the steel parts and admire it...would frankly be a shame to subject it to use now...next one I find that really needs going through will get tried out, though...

I will have some stainless OE-1 economizer springs in a few days...everything else is hit or miss with regards to having stock...

I like the period looking ones. The brass is great!

I think these clean up real pretty.

Bryant, many have done this conversion, the best setup I have seen was the B intake and exhaust manifold, the intake is larger for more air flow and the exhaust manifold kicks it out behind the engine like a T does. I would not go through all this unless you have went to larger valves, cam, head or hi comp pistons, the engine will run but to get the flow out you need these upgrades. Hope this helps?

Joe Bell wrote: ↑

Thu Nov 25, 2021 10:00 am

Bryant, many have done this conversion, the best setup I have seen was the B intake and exhaust manifold, the intake is larger for more air flow and the exhaust manifold kicks it out behind the engine like a T does. I would not go through all this unless you have went to larger valves, cam, head or hi comp pistons, the engine will run but to get the flow out you need these upgrades. Hope this helps?

Thanks! I have been looking at manifolds but am still not sure of the abc differences. what is what? The engine is fresh. Has the adjustable 350 Chevy valves. Will be getting the z-head. And now pondering a cam. With all that said I would also like to try a stomberg. Are we having fun yet? Iam at the beginnings of this journey and don’t mind trail and error situations

Bryant : The carb/manifold pictured in your original post is a B set-up, not Model A. One of the biggest mistake guys make in looking for a performance improvement is to over-carburate, (an old mechanic buddy of mine used to say "it's like puttin' a 650 CFM Holley on a lawnmower and expecting it to run perfect"). Those that have mentioned bigger valves and cam profiles are on the right track for a modification like this to a T motor, but don't forget that paper-clip crankshaft. As well, you mentioned a Z head but you might want to look close and compare a Prus head, in combustion chamber shape, head gasket surface area as well as machining tolerances. Good luck: Bruce

Bruce Compton wrote: ↑

Thu Nov 25, 2021 8:46 pm

Bryant : The carb/manifold pictured in your original post is a B set-up, not Model A. One of the biggest mistake guys make in looking for a performance improvement is to over-carburate, (an old mechanic buddy of mine used to say "it's like puttin' a 650 CFM Holley on a lawnmower and expecting it to run perfect"). Those that have mentioned bigger valves and cam profiles are on the right track for a modification like this to a T motor, but don't forget that paper-clip crankshaft. As well, you mentioned a Z head but you might want to look close and compare a Prus head, in combustion chamber shape, head gasket surface area as well as machining tolerances. Good luck: Bruce

Agreed. Prus head. I didnt catch the B carb. An A works well.
A B/C carb. May be too much. Like I said. An A works on a T & a B/C works well on an A.
You might gain top speed but low end performance may suffer. That would be the over carburation Bruce is warning you of.

Thanks fellas. That is why I brought the topic here. I figured someone has tried it. I know all about over carbing the engine but was unsure if that zenith would be to much. Prus head you say? noted. And thanks for all the info!

Thanks fellas. That is why I brought the topic here. I figured someone has tried it. I know all about over carbing the engine but was unsure if that zenith would be to much. Prus head you say? noted. And thanks for all the info! Iam relearning my ABC’s

Bryant. Dont be so quick to dismiss stock model T carburation. A good holly NH (or 2) can provide plenty of fuel to the "package".
I developed this configuration in my post model A carb experimentation period.
Why hasnt any body.....I wonder if........... It met certain criteria, like period & no fuel pump, simple & cheap to build. IMO, neat looking.
The "package' consists of an iron lizard hi compression head. Capped vaporizer manifold center exhaust out A 2" pipe to a wheeler type can. Intake is built from 2 stock manifolds. 1.5" exhaust & 1.75" intake valves. Scat crank. Stipe 280 cam? 2 NH's with exact fuel levels & synchronized. Hand throttle with an over riding foot throttle to shift the rux. 8V battery.
I wanted speedster performance from a fully loaded roadster P/U. She serves me well.

An important thing I learned on the first test drive was the front end needs to be "tight & right" to enjoy/control the extra horses.

speedytinc wrote: ↑

Sat Nov 27, 2021 9:48 am

Bryant. Dont be so quick to dismiss stock model T carburation. A good holly NH (or 2) can provide plenty of fuel to the "package".
I developed this configuration in my post model A carb experimentation period.
Why hasnt any body.....I wonder if........... It met certain criteria, like period & no fuel pump, simple & cheap to build. IMO, neat looking.

thumbnail.jpgthumbnail.jpgthumbnail.jpg

The "package' consists of an iron lizard hi compression head. Capped vaporizer manifold center exhaust out A 2" pipe to a wheeler type can. Intake is built from 2 stock manifolds. 1.5" exhaust & 1.75" intake valves. Scat crank. Stipe 280 cam? 2 NH's with exact fuel levels & synchronized. Hand throttle with an over riding foot throttle to shift the rux. 8V battery.
I wanted speedster performance from a fully loaded roadster P/U. She serves me well.

An important thing I learned on the first test drive was the front end needs to be "tight & right" to enjoy/control the extra horses.

That’s pretty slick! Love it! Iam a fool for linkages

John, I have duel NH 's on my Rajo four valve, plenty of power for me!

Joe Bell wrote: ↑

Sun Nov 28, 2021 7:17 pm

John, I have duel NH 's on my Rajo four valve, plenty of power for me!

Love to see a pix. Compare engineering. And an option for a future rajo head build.

John,
How did you get the lizzad head to run properly?
I have a couple I want to give a try.
Thank you, John

John bevardos wrote: ↑

Mon Nov 29, 2021 9:56 am

John,
How did you get the lizzad head to run properly?
I have a couple I want to give a try.
Thank you, John

I have several. 2 had spark plug water jacket leaks. All the sharp machining needs to be cleaned up. Nothing special otherwise.
Be aware, as I became, They were made in many compression ratios. One of mine is near 8-1 (will have to check specs) Good Idea to CC if you dont know.

For all the guys hoping to find a boost in performance with their bone-stock Model T's, here's something to ponder. Henry made over 15 million T's, all with either Kingston or Holley carburetors (Ford made a copy of the HN's too). If simply increasing the size (bore/venturi) of the carburetor would have even slightly boosted the (advertised) microscopic 20 HP of the T engine don't you think Henry would have been all over it, and especially with basically zero cost to him or the carb manufacturers?? Compare the bore/venturi size of any good aftermarket carb (except the U&J) to the famous Holley straight through and almost all of them are smaller. The very popular Stromberg OF is radically smaller than a Holley straight through,yet provides a significant increase in power and smoothness and does it all using LESS fuel. The difference is by achieving better fuel atomization and fuel-air mixture throughout the RPM and load demand range with separate designated circuits built into the design of the carburetor. Several companies realized the Ford shortcomings and offered replacements that were way better than the stock Ford carbs but were not cheap, while in reality, Henry was. The engine is basically a pump that has it's breathing controlled (limited) by how much it can inhale and exhale through the valves (size and lift), not by trying to force more fuel down it's throat. If you're talking Rajo or Frontenac heads,or Stipe cams and bigger valves, that's a different story.

Henry needed low cost, reliable, simple, and easily manufactured and serviced carburetors in great volume. They also needed to be able to handle a very broad range of climate and altitude and fuel quality and operator competence. As for horsepower, Henry reckoned that 20 was quite enough for the lightweight T, and he held operating economy to be of paramount importance. Millions of users agreed. The Model T was highly suited for its target market and the conditions under which most of them were operated. The carburetor design and intake manifold and cam profile were calculated to provide good low speed torque and good fuel economy. Most people in the 1910-1925 era had little occasion to travel at speeds over 20 to 30 MPH, and that's well within a stock T's performance envelope. For pleasure driving today, I'd like to have 33 HP and 2700 RPM cruise capability with full reliability and minimal vibration. That's available, at a cost....

So does any body know the CFM of any of the carburetors mentioned? what is a good starting point for stock engine? i am just looking for a easily available carb. i like pretty much all of them. but if you search for the zenith about 100 come up for sale for reasonable prices. i am not trying to over carb anything.

Bryant wrote: ↑

Mon Nov 29, 2021 2:11 pm

So does any body know the CFM of any of the carburetors mentioned? what is a good starting point for stock engine? i am just looking for a easily available carb. i like pretty much all of them. but if you search for the zenith about 100 come up for sale for reasonable prices. i am not trying to over carb anything.

NH sway back 29cfm. Straight thru 31cfm

i found a CFM calculator. i guess all you need to know is 1. the cubic inches 2. max RPM 3. Volumetric efficiency %

speedytinc I love that manifold & carb setup. I have tried many setups on my speedster. I find a adjustable large carb to be very good if mated with a good exhaust. But takes some tinkering while driving. My number one concern is getting equal flow to #2 & 3 as 1 & 4.Thus making two cylinders run richer than the other two. This seems to limit performance gains as the manifold flow is one direction then the other. Most all four cylinder engines are now firing 1-3-4-2 or 1-4-3-2 to even out the manifold flow and balance the air fuel charge in the cylinders. ( this is one of the reasons Ed Windfields 2 up 2 down engine ran so well ) Short of making a cam to change this or reversing the flow ( 4 INTAKES & 2 EXHAUST ) Has anyone tried making a manifold to improve this issue? Large plenum or directed flow.? Will 2 carbs help with this? ( it still seems you will get a on off flow) Just some random thoughts.
Craig.

Tinkering while driving. O yea. I have 2 3' rods to tune the 2 carbs while testing different speeds/conditions. The 2 carbs are manifold equalized. I suspect 1 & 2 or 3 & 4 can be richened/leaned for some effect. Plugs show same burn on all cylinders.

Bryant, sorry for not getting back with you. Hospital stay was extended until Saturday, so I've only been home at little over 24 hours. Will try to email you tomorrow.

ModelTWoods wrote: ↑

Sun Dec 05, 2021 11:40 pm

Bryant, sorry for not getting back with you. Hospital stay was extended until Saturday, so I've only been home at little over 24 hours. Will try to email you tomorrow.

Hey I hope all is well! Take your time. I’ve been trying to work out what the volumetric Efficiency % of the engine is. Lots of measurements Iam not sure of. Cubic inches, bore and VE% and you can dial in the CFM in theory you could handle.

speedytinc wrote: ↑

Mon Nov 29, 2021 11:00 pm

Tinkering while driving. O yea. I have 2 3' rods to tune the 2 carbs while testing different speeds/conditions. The 2 carbs are manifold equalized. I suspect 1 & 2 or 3 & 4 can be richened/leaned for some effect. Plugs show same burn on all cylinders.

Do you have any pictures of your intake build?

Bryant wrote: ↑

Mon Dec 06, 2021 9:27 am

speedytinc wrote: ↑

Mon Nov 29, 2021 11:00 pm

Tinkering while driving. O yea. I have 2 3' rods to tune the 2 carbs while testing different speeds/conditions. The 2 carbs are manifold equalized. I suspect 1 & 2 or 3 & 4 can be richened/leaned for some effect. Plugs show same burn on all cylinders.

Do you have any pictures of your intake build?

No. 2 stock manifolds cut up. The updraft, curved leg portion cut off & the edge (1/2 round) used as a filler on top as pictured. All brazed together.

Craig Leach wrote: ↑

Mon Nov 29, 2021 10:16 pm

Most all four cylinder engines are now firing 1-3-4-2 or 1-4-3-2 to even out the manifold flow and balance the air fuel charge in the cylinders. ( this is one of the reasons Ed Windfields 2 up 2 down engine ran so well ) Short of making a cam to change this or reversing the flow ( 4 INTAKES & 2 EXHAUST ) Has anyone tried making a manifold to improve this issue? Large plenum or directed flow.? Will 2 carbs help with this?

A single plane crank in an inline 4 cylinder engine (except the Winfield 2 up 2 down engine), has not evolved much since the age of our T’s. With this configuration, the firing order must “pair” the 2 front, or 2 rear cylinders. 1,2,4,3 is literally the same as 1,3,4,2 as far as the Siamese ports are concerned. It is this unequal timing of flow in each port that causes the unequal fuel delivery to the cylinders in the pair.

It is not the Siamese ports that are to blame... it is the ability to space out the firing sequence so that the intake pulses are evenly timed. Siamese ports were used successfully up into the 60’s on inline 6 and 8 cylinder engines, as the additional cylinders allow the ports to be used in an equally spaced manner.

There is no carburetor or manifold configuration that will overcome the unequally balanced Siamese port issue on a 4 cylinder engine. The Winfield 2 up 2 down crank allows the firing order to oscillate equally between the front cylinder pair and the rear, 1,3,2,4. Essentially this created the same effect as having 4 intake ports, which can also be done by building a “reverse flow” camshaft.