Marvel vs Model B carb?
- Thread starter old31
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Purdy Swoft
Well-known member
The model B carburetor is best for performance !!!!!!!
denniskliesen
Well-known member
I’ll put my vote to B if it’s a clean not worn out carb.
Railcarmover
BANNED
two different designs,B flows a little more than the Marvel.
from what you said about your setup you should try a single downdraft,Stromberg 97,Holley 94..get a carb and manifold swap the downdraft on when your friends aint looking
.You've done everything else,a down draft will really pull it together
from what you said about your setup you should try a single downdraft,Stromberg 97,Holley 94..get a carb and manifold swap the downdraft on when your friends aint looking
.You've done everything else,a down draft will really pull it together
Purdy Swoft
Well-known member
Larger inside diameter of the intake manifold will help some but not a whole lot . The model B intake manifold is an improvement over the model A intake manifold . The carburetor mounting flange on the model B intake is off set and is a pain to deal with .
Synchro909
Well-known member
I have never seen a marvel - not even sure they were available here but I'd take that over a B carb. If a 2 tooth steering box is fitted (like my cars). Modifications are required to fit a B carb. It tries to occupy the same space as the steering box so it is a no go. Not that it rally matters - B carbs are very rare too.
Railcarmover
BANNED
B' has a larger bore than a Marvel.
Both fit an A manifold,but to get full power from the B you have to drill out the A manifold to 1.25..or buy a B manifold.
all the more reason to go downdraft OZ..
Both fit an A manifold,but to get full power from the B you have to drill out the A manifold to 1.25..or buy a B manifold.
all the more reason to go downdraft OZ..
Terry NJ
Well-known member
I have drilled out quite a few A manifolds to 1.25+ with good results with a B carb. The 1.25" bore of the B allows it to process more air. The A engine does not breathe well in stock form. I would like to take a stock B carb and bore the throat out, but I feel that.020 - .030 is about the max you could go with it, but it would be an improvement. I believe Dennis Piriano has done extensive dyno testing that includes A-B carbs, Drilled and undrilled manifolds and various other mods. Check out Piriano's model A Tests.
Terry
Terry
Railcarmover
BANNED
Model a engine flows air at about 16o cubic feet per minute,stock a zenith flows at about 80 cfm,Stromberg 97/Holley 94 flows around 170 cfm.
See your engine as an air pump,use all the air it can pump creating useable atomized fuel.basically match cfm of carb to cfm of engine.doing this increases economy and power,the engine gains efficiency by using all its volumetric capacity to conduct useable fuel.
adding higher compression to the equation makes the combustion process more efficient,higher compression yields a faster more efficient burn.when you burn fuel at a higher efficiency rate your engine actually runs cooler.
See your engine as an air pump,use all the air it can pump creating useable atomized fuel.basically match cfm of carb to cfm of engine.doing this increases economy and power,the engine gains efficiency by using all its volumetric capacity to conduct useable fuel.
adding higher compression to the equation makes the combustion process more efficient,higher compression yields a faster more efficient burn.when you burn fuel at a higher efficiency rate your engine actually runs cooler.
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30 Closed Cab PU
Well-known member
Am just curious,- was this not known in Henry's day? Why was the carb designed restrictive and not as efficient?
Hoogah
Well-known member
Synchro, I bought one at the Ballarat Swap last year. Actually thought it was a Tilly until I compared them more closely. Of course, it could have come off an imported car?
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Synchro909
Well-known member
Wow, so there is one here! Does anybody know if parts are available for them or do Zenith or Tilly parts fit?
Sidetracking a bit here but in one of my sheds, I have a carb that looks like a Zenith but is a Japanese copy. From memory, It is KTK branded and made by the Tokyo Carburettor Co Ltd.. It looks like a zenith - does anybody know about those and do zenith parts fit? What drew my attention to it was the colour of the enamel on it - a deep maroon. I've never seen another one like it.
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Railcarmover
BANNED
They had problems getting the Hp up to where they wanted it in '27,Harold Hicks during his famous redesign utilized a Zenith in his work to bring the engine from 22hp on the brake to 40hp (valve cooling played a big part too). Ed Winfield was making his downdraft carbs during A production..performance improvements created an cottage industry,an owner could bolt on almost double the power in an afternoon.
Detuning production engines has gone on since the beginning,for a variety of reasons,from longevity to ease of maintenance and reliability.The down draft two barrel emulsion tube Stromberg powered the v8 line from '33 to '37 or so,when Chandler Groves designed the what became the Holley 94,that was used by Ford till 1957. Both are proven carbs and match the flow rate of the model a 200 cuin,V8's were 221 cuin at the time.For those who wish a performance increase without overfueling this setup is hard to beat.Alot of folks use 2 of them,internal improvements can bring the A CFM efficiency up..I personally shoot for the single downdraft modified flathead,it yields great reliability and almost double the performance of the stock A engine.
Herb Concord Ca
Well-known member
best resource in the US is Rennier Brothers in Michigan. Don't know about Australia.
Zenth/Tilliston parts can't be used on a Marvel.
It's a good carb.
Zenth/Tilliston parts can't be used on a Marvel.
It's a good carb.
Synchro909
Well-known member
Thanks Herb and Railcarmover. I don't know of a parts supplier in Australia for those carbs so Renners would the only option but at those prices, by the time I had things in my hand, I'd be up for about $250. Yikes!
As for Zebith parts - do they fit the KTK carb, assuming someone knows of them and is therefore ab;le to answer. It looks to me like they should but threads might be different, Japan being metric.