air-friction carb

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matthewejacob
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air-friction carb

Post by matthewejacob » Wed Jun 07, 2023 3:48 pm

Does anyone in here know how to adjust one of these? I've been scouring the web on these things and have found a bunch of old adverts for them but i can't find a manual or anything about where the adjustments are. the mixture screw seem pretty obvious, but is it a set it and forget thing because there looks like a jam nut/wing nut on there to lock it in place. I picked one up on ebay that looks to be really nice for a reasonable price. I found this old thread on here https://www.mtfca.com/discus/messages/8 ... 1261676994 but was no real adjustment tips. and it kind of veered off course like happens frequently in our hobby! any help would be appreciated.
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Scott_Conger
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Re: air-friction carb

Post by Scott_Conger » Wed Jun 07, 2023 4:06 pm

For $25 you can read all about it

https://www.thecarburetorshop.com/Carbs ... _other.htm

view the patent here: https://patents.google.com/patent/US1088181

I would think that a safe bet is to start your car and warm it up...then remove the carb and install the Air Friction Carb...loosen the wing nut and screw in the needle until it seats the jet and then back out 1 1/2 turns...start the car and adjust the needle as you would an NH. I don't have one directly in front of me but carbs of this type are going to have a pretty standard jet orifice, a pretty standard needle and almost always a 1/4-32 thread which almost dictates the opening turns.
Scott Conger

Tyranny under the guise of law is still Tyranny

NH Full Flow Float Valves
Obsolete carburetor parts manufactured

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DanTreace
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Re: air-friction carb

Post by DanTreace » Wed Jun 07, 2023 6:08 pm

Jay Busico posted these scans of the manual for the Air Friction back in the Accessory of the Day threads.







a copy larger.jpg
b copylarger.jpg
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Image 4-16-23 at 12.29 PM.jpeg (60.24 KiB) Viewed 768 times
1924 Air Friction.jpeg
1924 Air Friction.jpeg (73.66 KiB) Viewed 768 times
The best way is always the simplest. The attics of the world are cluttered up with complicated failures. Henry Ford
Don’t find fault, find a remedy; anybody can complain. Henry Ford


Topic author
matthewejacob
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Re: air-friction carb

Post by matthewejacob » Wed Jun 07, 2023 10:39 pm

Ah yes, that's what I was looking for, thanks! And Scott, that's about where I thought I was gonna end up. Just trial and error. Basically I bought this carb because, well I can't afford a Stromberg, and because the old nh is just so crude and we have a lot of hill where I live and I was hoping something with a little more adjustment may help a little. Not sure that it will but it's worth a shot. I can't climb anything with that nh unless I'm in low. And I've completely rebuilt the engine, bored, high compression pistons, adjustable tappets, basically everything but the balanced crank (which I also can't afford) but it's such a dog. Runs fine on flat ground but these hills are just too much for it. I've tried different nh's even, thinking maybe I have a passage locked or something but they all act the same. Makes no sense to me and I've built engines half my life. It's got me stumped for sure so the only thing I could figure is maybe those nh carbs are just so crude they can't handle steep hills.


RVA23T
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Re: air-friction carb

Post by RVA23T » Thu Jun 08, 2023 12:43 am

Did you try an NH with Scott's larger full flow float needle set? I found it to be a great improvement on hills because it keeps the bowl full. 3 or 4 mph more on my test hill that I hit at 45mph and would top out at 25 to 27mph in direct so it was closer to 30 mph with Scott's needle and seat set but I still moved up to a Stromburg OF because that hill is now 35mph with the OF. I have the NH in reserve should the OF need servicing one day.
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Topic author
matthewejacob
Posts: 11
Joined: Sun Aug 21, 2022 12:31 am
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Re: air-friction carb

Post by matthewejacob » Thu Jun 08, 2023 8:19 am

The nh is completely stock, I have three of them and they all behave the same way. What made me think to change it is I'm working on a speedster and I have dual carbs on it and it does not lack in power at all, and that engine is stock internally. But you've given me some hope that I'm on the right track maybe.

My grandfather found a Stromberg in his parts and I was eyeing it and he said "you want it?" And I said do you know what that is? And I pulled it up online and showed him and he said, "maybe I should put that on my car". I said, yeah, you probably should! But I've been looking for one since because thier reputation is pretty good. No one complains about them.


Scott_Conger
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Re: air-friction carb

Post by Scott_Conger » Thu Jun 08, 2023 9:24 am

Matthew

when it comes to hills, I would bet that your NH's are NOT stock. The reason is, I'll bet that they've been rebuilt, and if so, the float valve is a repro with a too-small through hole. Because of this, fuel does not flow as readily into the bowl particularly on hills
Scott Conger

Tyranny under the guise of law is still Tyranny

NH Full Flow Float Valves
Obsolete carburetor parts manufactured


Norman Kling
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Re: air-friction carb

Post by Norman Kling » Thu Jun 08, 2023 10:44 am

Have you had other Model T's? They are a bit slower on hills than most of us are used to unless we have had a lot of T experience. Your rear axle gear ratio makes a big difference. Some have changed to 3-1 ratio which gives more speed on level and downhill, but they are slower going uphill. A Ruckstell axle or other reduction transmission will also give you more speed with less engine rev going uphill. Even the weight of the car makes a difference. Sedans are slower than runabouts or tourings. And even the number of passengers will make a difference.
For hill climbing, it's best to try not to stop while going uphill. Get a good run before starting up and slightly retard the spark as it begins to slow down.
Other things which cause problems going uphill are gros valve in carburetor. This is a ball valve in the float valve. The needle valve works best. Other problems are on cars with gas tank under seat, you need to keep the gas at least half full to climb the hill. also if the car set a while without driving, you might have thick varnish like deposits in the fuel line causing a partial restriction.
Anyway, good luck with your new carburetor. Let us know when you get it adjusted correctly, and how it works in your car.
Norm


Topic author
matthewejacob
Posts: 11
Joined: Sun Aug 21, 2022 12:31 am
First Name: matthew
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Location: proctorville OH
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Board Member Since: 2018

Re: air-friction carb

Post by matthewejacob » Thu Jun 08, 2023 10:58 am

I've grown up around my grandfathers T. We put a scat crank in his a few years back and the difference that made in power just from all that extra mass was pretty unbelievable. I guess I took it for granted. The hills are steep enough here that i had to actually put an electric fuel pump on mine because it left me having to turn around and back up in reverse a few times. it was nerve racking enough I thought i better address it! I haven't had an issue since. Mine is a depot hack and the tank is under the seat. The carb has been rebuilt with all new parts internally.

You are probably right in that I'm just not used to how it should behave vs what my expectations are. My grandpa lives in flat farm country so we have never had to deal with it. I live on the OH WV border where there are plenty of mountains to deal with. It will pull itself up a hill in low, at fairly high rpms but it's slow going. But even on flat ground once it shifts into high it's pretty sluggish until the rpms finally come up a little.

my first foray into how crude the NH was was with the speedster. I had origonally put two of them on it (just cause i wanted it to look period). boy was that a mistake! It was feeding it way too much fuel and there was no way to really limit it. so i scrapped that idea and went a different route. still has dual carbs but it runs much much better. that one is just a fun little project my daughters and I are building together.

I'll post back once i get the new carb on and see whether it was worth it.

Scott, you are right, I have rebuilt them but i was unaware that the replacement parts could actually cause a problem. I do have a few that haven't been touched. I'll take a look at what they look like internally. thanks for that advice. I really had no clue.


Scott_Conger
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Re: air-friction carb

Post by Scott_Conger » Thu Jun 08, 2023 11:08 am

FWIW - you needed a fuel pump to squeeze the fuel through a badly designed repro float valve

Not haranguing, just making a point for others in the future who are convinced that a fuel pump must be in their future. It doesn't have to be.

I'm looking forward to your drive report on the Air Friction. Lots of them were made, so they must work...I've simply never known anyone who drove one as a regular driver...to test them, yes, but not for everyday.

Good Luck
Scott Conger

Tyranny under the guise of law is still Tyranny

NH Full Flow Float Valves
Obsolete carburetor parts manufactured


Topic author
matthewejacob
Posts: 11
Joined: Sun Aug 21, 2022 12:31 am
First Name: matthew
Last Name: jacob
* REQUIRED* Type and Year of Model Ts owned: 1925 Depot Hack, 1918 speedster
Location: proctorville OH
MTFCA Number: 0
Board Member Since: 2018

Re: air-friction carb

Post by matthewejacob » Thu Jun 15, 2023 8:15 pm

Thought I would give an update, I got the carb on and adjusted it. It definitely has made a difference. For one, when you start it cold just a brief choke and it instantly fires up and absolutely no sputtering until it's warm enough to smooth out. Just a smooth idle out of the gate. It's never done that. I'm not sure about all the claims air-friction made about power :lol: but it definitely will pull better up the hills. It's a bit more responsive as well. Anyway, it is an improvement none the less. But I suspect Scott is right, that the nh I had probably did not have the correct parts inside. That pic is before I got the linkage all straightened out. It definitely is built like a tank. Brass levers and insides. I'm happy with it.
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