If your inner speed demon chuckled and said "Well Seth, of course the answer is TWO U&J carbs!" then you'd be right!
Now granted, the two carbs I had on there before: Zenith S4BFs, those are nothing to sneeze at. But these babies are a noticeable upgrade. I was topping out around 70 mph before, it'll be interesting to see if that changes much one way or the other. (Hint: I have a strong suspicion the new number will be higher). The acceleration is definitely improved. WHEEEE DOGGIE
That's cool Seth.
Do you have any video of it driving?
The only thing cooler than that would be THREE U & J carbs!!!!
The are amazing!!
Once again I'm envious of something someone else has got! Seth you have increased your "Cool" factor X 3.
I guess the "matched" venturi's are working.... Post some videos for us to see. We always say "we like pictures" but we also "like videos"
Stan, thank you for the info on the Holley G venturi being a drop-in replacement for the U&J venturi. It was interesting because they are about dead even length-wise with the pot metal venturi, but much more open. They did just drop right in and after a little fiddling with the main needles she was purring like a tiger.
Don, no video driving yet but I will make one soon. If not today then tomorrow.
Mike, LOL thanks!
One of the fun parts is I didn't even have to hook up a choke wire. She just cranks up. Here's a video of it just cranking up and running. Lol, I made myself jump because I didn't advance the spark before revving it. This Rajo 4 valve prefers to start with spark retarded, and then just advance it all the way and leave it.
Sorry I can think of a lot of things that would be more fun.
Most of them can't be mentioned here!
At first I was surprised that no one mentioned the other fun things but then remembered that most of us are old and have a hard time remembering fun things beyond working on our Model T.
(Burger help me out here!)
You can go as fast as you want, but my fun thing is spending slow time with my granddaughters and remembering the times I did things with my dad
I love it!!! Seth, a lot of the aftermarket carbs used parts from Ford stock carbs. It was a lot cheaper to buy venturi from the Ford dealer for 18 cents each than to tool up to make them.
Here is the only complaint about U & J. There is no idle adjustment. However, it is easy to fit one. One the side of the carb is a passage that is soldered shut. That can be drilled and tapped, an adjustable needle fabricated and used to adjust the idle mixture. Not much too it, I haven't made one for quite awhile but as I recall, it was only a couple hour deal.
They are just a fine Carb!! I picked up one at Chickasha and -- as you know -- bought what is probably the only NOS one in existence. It had the choke setup with it and the pre heater, all the literature and was in the original box when it was on ebay. The seller threw it away before he shipped it because it "Was all ripped up and smelled like Mice." ARRRRGGGGGHHHHHH!!
I'm going to do a little short thread on another similar carb I picked up a couple weeks ago. A CYCLONE!! Never seen or heard of one before. I'd like to hear it run. Looks like a great idea. If I was rich I would reproduce it. Check the new threads.
Naughty cool Seth! That stack music is awesome!
Sounds and looks great.
I have a really nice U&J with manifold that I want to put on my Touring. I just need to figure out what to do about the cork float and the garbage ethanol fuel we're forced to use.
Do you need to borrow my synchronizing tool again or have you made something up to do that?
I bought my own John, it's electric works like a champ.
Great looking car and a nice looking set up on the carbs. I was going to ask you if you fabricated your shocks or were you able to purchase them somewhere?
Speedway Motor sells lever style friction shocks
Must sound bad a$$ tooling down the road clocking 70
One of those U&J's looks familiar.
John - the shocks came from eBay. If you search "friction shocks" the second listing is a pair of red primer ones. I painted them black, $40 for a set of 2. I got the rod ends from QS Components through their eBay store as well.
Between the friction shocks and the panhard bars my speedster rides like a Cadillac now and corners like an F1 racer. Ok maybe I'm exaggerating but the difference is ridiculous. ESPECIALLY at 70 it handles bumps very nicely. I thought before these two upgrades I needed a Ross/Sprague/30's Ford steering box to go fast and not be squirrelly. But now with them the stock steering works fine and feels rock solid even at speed.
Gary - its pretty fun. She's only turning 1600 rpm at 70 mph though so the engine isn't screaming. It's not quite the same, but when I open the let-pipe it sounds like a Harley in terms of volume.
Question: what can I paint the bowls with that gas won't eat off? When I go back to my parents I have a powder coater that will work perfectly, but is there a paint that is gas-resistant?
Dupont Imron, or other epoxy. Dave in Bellingham,WA
Could we see a frontal shot of the shocks please.
On my frame there were bolts there instead of rivets, so I just swapped them for different bolts to accommodate the shock mount. I then welded another attachment point to where the fender braces had been cut off.
Very cool twin carb setup Seth! I'm glad to see another T with twins, I'm planning on running 2 Winfield barrel model V carbs in my 4V Rajo, so your post is motivation👍
Here's video of speedster zipping along. About halfway through I open up the let-pipe so you can hear it.
It looks like your hard work paid off for you. Enjoy
65? Yikes! Yet listen to that engine. Just stretching out!
Love that vid Seth!
Seth - with 1600 rpm at 70 mph you have very tall gears, I get a 2:1 final drive when calculating?
With 3:1 mine would turn about 2250 rpm - but I've got to mount shocks first to dare trying
It seems I was a wee bit high even? I have a 3:1 rear end and I believe the Chicago overdrive is 1:1.55 (or .645). My wheels as measured at right at 30 inches in diameter measured at the outer edge of the tires. So yes, final drive is right about 2 engine turns for one wheel turn.
Check my math:
70 miles/hour x 5280 feet/mile x 12 inch/foot gives 73,920 inch/minute
73,920 inches/minute x 1 wheel turn/(30x3.1416) inches x 3 driveshaft turns / 1 wheel turn x .645 engine turns/ 1 wheel turn gives 1,518 engine turns / minute. Give or take a little.
I could be off on my tire size some but this is pretty close. I can tell you anything over 60 in Chicago OD and then engine doesn't feel like it's working hard at all.
I didn't challenge your calculation, just amazed that you have such a strong engine that it pulls so good with that high gearing
Have you tested it long enough to get a feeling how much gas the U&J:s wants compared to your earlier engine evolution stages? (still worth it, I bet, even if they're gas hogs )
So far the pros/cons of the U&Js verse the Zeniths seems to be that the U&Js are actually noticeably better on gas when doing anything over 50. The Zeniths were fine and got 23-25 mph as long as I wasn't really moving. If I wanted to cruise on the highway though they'd suck some gas down with a quickness. They definitely idle better, accelerate better, and have more top end.
However. The U&Js have proved an absolute bear to start once the car is up to temp. I don't know if I have the floats adjusted too high, or what. When cold the car starts on the 2nd or 3rd pull without having to use the choke. When hot and allowed to sit for a few minutes there's a 50/50 chance that if I open the throttle way up first she will crank, or she will act flooded and want to not crank for 15 minutes no matter what I do.
I've tried opening the throttle and pulling through several times to "clear" it but if she doesn't start on that first or second crank then she's gonna fight me. I chalk a little bit of it to just learning these carbs and what they like and don't like. But if I knew more about them then maybe I'd know what to tweak to make them easier to start when hot. What I've noticed works best is if it doesn't start right away, I cut my electric fan on and let it sit for a few minutes and then it starts right up.
Those intake tubes running right over the exhaust manifold are probably heat sinking the fuel coming in -- causing at least some of the hot start problems. The hot intakes vaporize the fuel which makes the mixture too lean to burn in the cylinder.
The steel manifold may be part of the problem, the standard aluminum manifold U & J used cooled off a lot faster.
Also, the Zenith Venturi is smaller, and the orifice is in the direct air path, making for better starting than the U & J which is pretty much just a little puddle of fuel for the air to pick up.
Put a self-commencer on instead of the stem winder.
Stan your advice and input is ALWAYS welcome and I do my best to heed it. I have thought during carb experimenting "Man, I need a dang starter." I will be very tempted to add one the next time I have the engine out. My current flywheel doesn't have a gear.
I may see if I can get my buddy to replicate this intake with aluminum plus some speed fins for cooling. Makes sense that cutting my electric fan on makes the biggest difference in the car starting back up.
Thank you sir
Even tho the "Experts" disagree with my carburetor statement that "The first thing you have to accept when you study carburetor theory is that there is no such thing as vacuum. There is pressure differential between the chamber that is being filled with vapor and the outside atmosphere. The pressure differential is some part of the nominal 14.7 lbs PSI at sea level, the air and fuel mixture is forced into the cylinder by that, not 'drawn in' by vacuum."
If you think of it that way it makes understanding what is going on in the carb and manifolds a lot easier.
(Hoo boy, watch the arguments start now. I'm probably about to be told I'm an idiot again by somebody. Not Seth but somebody)
Back to the shop. Back to the shop. Back to the shop.
Stan, Im with Seth, and always heed your advice when it comes to carbs. Now if for some reason some one else does not post something bashing your knowledge and calling you an idiot, I guess Seth and myself could team up and say bad things about you, and call you an idiot a few times. We would be lying, and making things up. But if it would make you feel better we could maybe give it a try.... have fun and be safe .... Donnie Brown ...
to add to what Stan said another person who knew a thing or two about carbs (and a few other things) would say the piston does not pull air in it just creates an area to be filled by what ever pressure is available. By the way that person was Ed Winfield
Seth, Looks and sounds great. I am sure that you will figure out the warm starts. Fuel injected aircraft have warm starting problems because of heat saturation. I love the tall gears, my car could use an over drive. Thanks for the info on the friction shocks. Stan, Your a f-en Genius! With a few suggestions from you, I am now pleased with the performance of my stromberg carb. I was ready to throw it away. You mentioned that I might try a bit larger idle jet, and that was the ticket. As you can see, I am not running the choke horn. It has always started, idled and ran full throttle well, there was just nothing in between. Opening the idle jet, let me open the idle air jet which makes the carb have a mid range. The air jet actually becomes the mid range jet. Some day I would like to try a needle screw instead of the idle jet. I also don't have a float needle cover nut, It lets me flood the carb for cold starting. Thank you.
Well how's she running after you had some time with the U&Js?
I haven't had a chance to fool with them much. I've been doing finals all this last week since it's the end of the semester. I'm working on my mechanical engineering degree.
Here's what I've discovered: even with identical venturis I'm getting uneven flow, but it's a lot better than before. I investigated and it turns out the two U&Js are machined differently inside. One is 1/8" deeper than the other, that one has more room to flow more air.
So! Donnie Brown has sent me his U&J body. I'm hoping to get it machined for a Holley G bowl next week. Inside it matches the same depth as the shallower of the two carbs, and I'm gonna send him the non-matching one since he's only gonna run a single carb.
Also, I'm looking for some aluminum tubing to make my intake manifold from. I can find 1.25" ID straight tube no problem, but what I really want is some 1.25" ID, 90 degree bend, but with a 9" to 12" center line radius. When I made my steel intake a forum member recommended I get some steel conduit from Home Depot and that worked perfectly. It was 1.25" and I want to say the CLR was about 12". If anyone has can bend me some tube I'd love to buy it, or if you know where I can get some. Doesn't have to be exact, I can go down to 1" if that's easier.
I want that nice sweeping bend because it works really well with my 4 valve head and dual exhaust manifold. I can make a new manifold out of straight tube but it'll be a lot closer to the exhaust manifold and it won't be nearly as streamlined as the current steel intake. I'm also working with a friend from school, he has a computer program that will use a model of the intake and the temps involved and it'll tell me whether some cooling fins will actually help or not. It'll also give me an idea of how much surface area it would take to make a difference. Right now I'm coping with the hot start problem by running my electric fan for a few minutes before trying to start and that seems to do the trick. It lets the hot intake cool enough to get going.
What a great car.
Would panhard bars offer any advantage to non-speedster Ts? Can they be used without shocks?
Hey Constantine - absolutely, I think they are a tremendous advantage whether speedster or not. They make a huge difference in stability and handling. The shocks just make the ride smoother and help kill bouncing after bumps.
If anything I'd think a bigger body T would notice the difference panhard bars make even more than a speeder. They kill all (well maybe not ALL, but most) of the sideways sway on the springs when turning and also dramatically reduce body roll. I would think a touring/centerdoor/Depot hack would feel much nicer.
I didn't want to say anything about the difference in the body depth of the U & J's since you seemed happy with it like that. I don't know exactly the reason but my guess is that one is for the Overland version of the carb and one is for the T. It might just be an earlier and later version of the design. There are several variations of that top throat including one that sets the throttle shaft 90 degrees to the block instead of in line with it.
Sounds like you are gaining on it. If I had a suggestion to make them run better it would be to drill the idle supply passage - that is soldered shut on the side of the throat - thread it and install a needle adjustment to control the idle mixture. It also IMHO makes them accelerate a little better when you open the throttle.
I'm going to be working in the shop today trying to get a couple carbs out before I go to Missoula this evening to record some radio liners and thank you spots for the station, I'll try to remember to check my NOS U & J and see exactly what the depth is.
Seth: Regarding your carburetor balance problem with uneven flow. Because you are making a new intake to fix the carburetor heating problem anyway.
In the pictures it looks like there is room to move the carburetors closer together, try to get them somewhat closer to each other,
they should balance better because they will act more like one carburetor that way.
I hope your finals went well.
Seth: I thought of something later in the day regarding your steel intake manifold heating problem. You could try wrapping the intake with that exhaust header pipe wrap that is sold.
It is mainly used to insulate the exhaust headers from overheating the starter. It would probably work in reverse on the intake and if doesn't it would be easy to remove.
I see it advertised in the Street Rodder magazine from time to time.
Seth, if you are going to make a new intake manifold, perhaps you should look into the placement and size of the balance tube. I have no practical experience in the field, but I have not seen a balance tube anywhere near the same size as the intake tubes. Whether this has anything to do with your hard starting I don't know.
Hopefully, someone will chime in with greater knowledge than me. That shouldn't be too hard.
Allan from down under.
Lots to answer:
Uncle Stan, the car does run well and strong as-is. However, there's still a noticeable difference. I can balance them but it's huge adjustment where the one carb is mostly closed and the other is way more open. Lol, if it accelerates EVEN BETTER with the idle passages converted to needle adjustments, that's kinda scary cause it already accelerates absurdly fast.
Kevin, I thought about wrapping the intake with header wrap as well as putting a heat shield between the intake and exhaust. The thing I'm afraid of though is while the wrap would make the car able to re-start longer than without, the real issue is once its sat there and gotten hot it'll stay hot longer because the wrap will act like an insulator.
I have finally found some tube like I want but there's a $100 minimum order. I'm gonna just go ahead and bite the bullet and maybe I'll make several intakes.
Allen, I started out with a much smaller balance tube, but on the advice of the forum made it the same size as the runners so that it would act more like two carbs attached to a single plenum. I do like how the current intake looks, but I think I'm gonna try having the front carb swept back 2" instead, that'll bring both carbs a lot closer together. That will also more closely mimic a normal intake made to run two carbs.
If you read up the thread I believe Stan is right that it's the exhaust heating up my intake. If I cut my fan on it cools everything off a lot faster and then the car fires right up. I think even with an aluminum intake I'll still need the fan, but it'll just cool off way faster than the steel intake.
It sounds like your intake is made from thin wall tubing which is going to head up really fast compared to a thicker walled intake. Try using the heat shield first, that may be enough to solve your problem, make it out of aluminum and have the exhaust side polished if you can. When I owned an Model A I used the polished aluminum heat shield to protect the ignition condenser after loosing condensers all the time in my Model A, never had condenser problems after that. You may be right about the wrap, you would have to try it, it would depend on how hard it was to remove if it didn't work.
If you make a new intake, I think if you are going with the carbs closer together it will help. Remember that a Model T fires 1,2,4,3 but a modern four cylinder fires 1,3,2,4. The problem with the Model T firing is it's using: front intake port, front intake port, rear intake port, rear intake port, causing problems with the mixture flow with the way your intake is set up. A smaller balance tube might help by making things act like two, two cylinder engines, but changing that now isn't worth the effort.
You have a really nice speedster, keep up the good work, this will sort out.
Well, since you are going to have a whole chingo of tubing to play with, my thinking is you should make the intake manifold in two pieces with a plate on each section at center where it joins together. Then make a variety of plate "restrictors" where it fits together. Just start with a small hole and gradually make it larger or make several plates and experiment until it runs best.
Personally, I don't think you need a balance tube as much as you need a restrictor between the two carbs. The rear carb is feeding 3 and 4, the front carb is feeding 1 and 2. Just a small hole -- too small to carry the full intake charge -- should balance them if you have the carbs matched. With the carbs that far apart and a big hole between them you are blowing the incoming charge back and forth in the manifold.
Again: In "CARBURETOR THEORY", there is no such thing as vacuum. There is only pressure differential between the outside atmosphere and the internal chamber you are trying to fill with a charged mixture. Nothing is "sucking" anything in. As the engine turns it is making space available to be filled by outside air pressure; 14.7 lbs per square inch at sea level. As the engine turns over it is moving the existing mixture back and forth in the manifold and since the carburetor throat is open to the atmosphere it may be pushing the incoming air back out and mixing so much air with the available fuel it does not have concentration enough to burn.
I finally had time to install one of Stan's fancy U & J carbs on my 24 Fordor, a little tweaking and it runs smooth and idles good.