demystifying Stromberg carburetors (resources for newbies)

[hopsedge]

Here are a couple of websites that may help to demystify components of Stromberg carburetors for newbies like myself. The diagrams and descriptions of the Strombergs in the WSM are good, but these websites include color illustrations and additional step-by-step instructions that complement those in the WSM. I would of course default to the WSM if there are obvious inconsistencies with the websites, but I found the color illustrations especially useful to help interpret the black and white WSM diagrams. Happy tinkering.

https://www.howacarworks.com/fuel-systems/how-to-overhaul-a-stromberg-carburettor

https://www.howacarworks.com/fuel-systems/adjusting-a-stromberg-carburettor

 

[Tim R]

If your Strombergs require any money being spent on them have serious look at fitting the twin choke Weber and curved inlet manifold before you spend anything. Unless you are keeping the car concours there is nothing to be gained with Storms. They go out of sync if you use the car properly, split their diaphragms regularly (always at the worst possible moment) and need constant topping up and fiddling with. The curved manifold set up is fit and forget. The car is faster, much smoother and way more economical plus you never need to mess with it. I went from getting 260-280 miles from a full pair of tanks on Stroms to 380-400 miles with the Weber. The guys at Alpine Innovations sell the kit and it will be the best thing that you ever do for your Alpine.
Tim R

 

[hopsedge]

If your Strombergs require any money being spent on them have serious look at fitting the twin choke Weber and curved inlet manifold before you spend anything. Unless you are keeping the car concours there is nothing to be gained with Storms. They go out of sync if you use the car properly, split their diaphragms regularly (always at the worst possible moment) and need constant topping up and fiddling with. The curved manifold set up is fit and forget. The car is faster, much smoother and way more economical plus you never need to mess with it. I went from getting 260-280 miles from a full pair of tanks on Stroms to 380-400 miles with the Weber. The guys at Alpine Innovations sell the kit and it will be the best thing that you ever do for your Alpine.
Tim R

Thanks Tim. In my relatively brief time of Alpine ownership I’ve heard the entire range of the spectrum from “There’s really no need to get rid of the Strombergs” to “Why n the world would you not do the Weber conversion?” Rarely have these sentiments been supported with anything tangible. Your report of significantly better gas mileage, however, is compelling. If anyone happens to visit our post here, I’d be really interested in hearing equally objective reports about the conversion. Thx all.

 

[Acollin]

I simply enjoy the tinkering needed to dial in the stroms. I just hope the parts supplies will out last me!!!
Thanks for the websites, but for my understanding it is not always the carb rules and regs that keep things from going as one would hope or expect. Understanding how things work is step one, but making observations and listening is what primitive systems require — Like balancing with a length of rubber tubing Is what keeps me engaged.
Ex: we all know jets need to be “centered”, but I learned that a close look is better than a “sharp rap” with a spanner. Also, I was adjusting my choke on the stroms and when manipulating the cable, I heard something that sounded like a twisted multi- wired cable fraying in a housing. The choke cable is solid- not fraying- and found that I had ever so slightly bent the cable end and it was rubbing/ scratching on a carb bit. All it took to repair was a push with my finger.
I can, of course, appreciate and understand the desire to up grade and improve upon systems, but I enjoy the more primitive systems for better or worse. I’ll let the next owner do what ever is necessary to keep it on the road.
be well all
Andrew

 

[Shannon Boal]

I have Jerome's kit operating about a year and a half. I get 25 or a bit better with U.S. gallons. I have fuel logs for this vehicle going back to 1968, can look and see what it got when new. My dad said it got 25 MPG at 70 MPH on the interstate.

 

[Shannon Boal]

Ex: we all know jets need to be “centered”, but I learned that a close look is better than a “sharp rap” with a spanner.
be well all
Andrew

I second this eyeball centering, and the figure it out part. One other thing; I had one carb running rich, traced it to o-ring rotting in jet assembly. Fixed that, then the other one rotted, went rich. Modern fuel, apparently. Plus my oil reservoir leaked down every three days. I guess I could fix all that, but then you have the only design fault.... no accel pump.

 

[Tim R]

Shannon,
I think there might be something not quite right with the tuning on your car. A US gallon is bigger than a UK gallon and even if I drive like a total maniac I couldn't get down to that few miles per U.K. gallon. Even my son's Automatic Alpine returns a lot more mpg than that.

We drive our Alpine all year round and work it hard. It is bored to plus 0.060, has the Vizzard head fitted to bowled pistons (because of repeated head and block skims over the years) and runs a non-overdrive diff with an overdrive gearbox. We measure our mileage by the tracker which ensures that it is 100% accurate. Like you we keep detailed fuel logs.
When running in and staying below 60mph I returned my best ever figure which was 42.1mpg (U.K.) The last three fill ups have shown 37.83mpg, 37.76mpg, 37.08mpg (U.K.) the worst that I have ever recorded was 28.79mpg (U.K.) At least once a month we fill up at the garage near our house (99 octane, currently no ethanol) we drive around 350 miles to see my grand daughter and back and then refuel at the same garage. Sometimes we are almost at 400 miles before we refuel.

This video is of us doing the trip we regularly do back in 2021. The speedo shows the mileage covered as 329. We ran on 97 octane fuel on this trip and returned over 33mpg U.K. If we had gone from the tracker mileage the mpg would have been even higher as the odometer reads slightly low.

 

[Mike O'D]

Tim - UK gallon is bigger than US gallon - about 20%.

 

[husky drvr]

What's bigger a US gallon or Canadian gallon?


The Canadian gallon is slightly larger than the US gallon. The volume of the Canadian gallon (also known as an Imperial gallon) is 4. 546 liters, whereas the volume of the US gallon is 3. 785 liters.

Gallons expressed as liters.

Hope this helps,

 

[Tim R]

Apologies, I looked on a comparison site and misunderstood what it was saying! That means that the disparity is less but I would still expect Shannon to be getting more than about 29-30 mpg equivalent.

 

[Shannon Boal]

I look forward to achieving your results, Tim! It is running better than ever, so I will check it again....

 

[toolsnob]

I highly recommend Alpine Innovations Weber Kit. The kit arrived quickly, very easy to install and was instant improvements over the dual strombergs. If you ever need tech support Jerome will call or email very quickly. I don't have mpg comparisons (and I really don't care, I don't driver the car to hyper mile) but seat of the pants, cold start, idle and simplicity of the system is worth every penny.

 

[Shannon Boal]

OK, have new data for fuel economy.
Series V, 135,000 miles 0.30" rebore, Jerome's manifold and Weber 32/36 carb, stock exhaust, cam was welded up and reground maybe not quite original now. Odometer road calibrated by milepost vs. readings is about 3.4% low. Tank filled until within 1" of slopping out. Non-ethanol from the same station. 477 miles (times 1.034 correction). 19.6 US gallons varied, but moderate driving. 25.2 MPG
Now as it happens, I have old data. Original owner logged all fuel from day one. Hard to read fading ink, but pencil entries good.
At 42000 miles, broken in, all original stuff: 424 miles two refills totaling 19.4 US gallons 21.9 MPG
60000 miles 180 miles 7.1 US gallons, 25.3MPG
This Alpine gets about 25 MPG (US Gallons) and always did. It rolls freely and has no abnormal frictional losses. It's odometer readings have been verified. I think two things; the Alpine V camshaft has enough overlap to waste a bit of fuel, and most people don't consider their odometer's accuracy. Should we start a new thread for this?

 

[husky drvr]

25.3MPG

That would be 30.39 MPG when converted to Miles per Imperial gallon.

Shannon,

Do you have overdrive fitted in your Alpine?

Just curious,

 

[Shannon Boal]

No overdrive Don. 3.89 rear axle ratio, tall-ish tires. P195/60-15 about 24" diameter

 

[Tim R]

By way of an update to the previous discussions. I have had differential problems with clonking and noise in recent weeks so today I drove 252.77 miles to a shop to get the diff changed. I THOUGHT my diff was a 3.89, it wasn't it was the much rarer 3.7. My diff was knackered so I replaced it with another 3.7. This 3.7 diff was known to be good and came from a late Hunter fitted with an Automatic gearbox. The higher gearing definitely contributes to the high miles per gallon I routinely achieve in my Alpine. The car pulls this high gearing with no problem and no noticeable loss of acceleration in every day driving (If you were doing a drag race from the lights you would notice it I'm sure).
Today I used 30.59 litres of petrol over 252.77 miles. This was mostly motorway and the top speed was 73mph (actual from tracker). That equates to 37.51 mpg (Imperial) I'll leave it to someone else to calculate what it is to US gallons!. It gives me a range of over 400 miles to a tank full of petrol.
The car has overdrive, is bored +0.060 with dished pistons and the Vizzard Head Modification, fitted with the Club Weber Carb set up, curved manifold and forced air intake. tyres are 165/80 -13 Continentals.

Tim R

 

[Shannon Boal]

About 31 point something US gallons, very nice! Seems that gear ratio has much to contribute here. What camshaft do you have? Does right hand drive help?

 

[Tim R]

Shannon, there will be a video on the Sunbeam Alpine Channel in the next couple of weeks showing what the car is like to drive with a 3.7 diff. The camshaft is standard Series V. The block and head have been skimmed several times so the engine has the Vizzard modification but with dished pistons. She is bored +0.060.
A genuine 70mph in overdrive top (measured by the sat nav) equals 2850 revs so she is very long legged but there is no noticeable loss of drivability at low speeds and acceleration around town is more than enough. An identical car with a 4.22 would 'burn me off' from the lights I have no doubt but will then be revving much higher on the motorway.
I don't think having right hand drive helps with fuel consumption!
Tim R