I don't know how many of you follow the 'Opinions' forum, but one of the regulars there has said that her '67 120 wagon w/overdrive (M41?) and a single Weber has returned upwards of 35mpg on the road. I don't mean to question her credibility (have no reason to doubt her), but is this kind of mileage within reach of the 'average' 120 or is her Amazon an Anomaly?

You'd have to buy a Toyota Prius to match that, and given a choice between a 35-year-old Amazon and a Prius, I'd definitely opt for the former.

I was happy with my gas milage but now I'm concerned about my testosterone levels......
--
1967 131

Remember that this is a female driver, not one of us testosterone-laden
leadfoots!

On one occasion in my 122 wagon(2130 cc B20, street perf cam, M41) I made
283 miles using 9 gallons of gas in less than 5 hours. This was at
night in Panama, only 15 miles of that was divided highway.
--
George Downs, The "original" Walrus3, Bartlesville, Oklahoma

Brickboard;

IMHO, 35mpg is not impossible to achieve.

I think you hit it on the head: After the hardware (cam), and adjustment of the carb(s), the next BIG part of the mileage calculation is a function of the right foot...on my trip out to Chicago, where I wasn't particularilly interested in acceleration, but just making good steady progress, I got just over 30mpg...but the OE SUs (on a B18 +.030" overbore, "C" cam) are adjusted on the slightly rich side...I bet if I had to, I could tickle my mileage up to the mid 30s (by adjusting the carbs, keeping terminal velocity down, and accelerating to keep an orange on a saucer on the passenger floor from rolling off the saucer - sort of 0-60mph with a calender acceleration)...not a whiff of testosterone in sight (but lots of 18 wheelers and Echos and Priuses and kids on Ginger scooters coming up fast in the rear view mirror - no thanks)!

My typical around-town-mileage is around 20mph.

Cheers,
Ron Kwas

hey...
Quite true, I have a 144dl with the B20B twin SU... and also the M40 trannie. I get 13-14 km/litre on highway drives, going ~100-120km/h. That translates to about 35-39 miles/gallon ... the plugs look grayish brownish.... but the engine idles smooth, good power...and doesn't heat in traffic. (and it's hot bangkok stop/go traffic.) but the key to that if keeping my foot steady while driving. (although the numbers do look high, but I'm happy.) But city driving is a whole another story... does almost half of the highway numbers.

That's amazing...and you don't have an OD gear, right?

Did these cars get this kind of mileage when new, or are these heavily modified motors??

Actually, it's not modified... it's pretty much a stock B20B with better exhaust. (which I don't think has much to do with it.) But the thing is that I tweak my carbs pretty often to get the mixture... I also think the light oil in the dashpot of the SUs helps too... cause I tried some 40 engine oil in the pots and my plugs turned black. I use some c10 oil... (don't know what you call it... it's for the spindle of the latch.) It's pretty light, but seems to get the engine running good. I also check my plugs often for proper clearence. And maybe it's my luck to have the engine running like this. But as I said I get pretty bad milage in city driving (something ~7-9 km/l) While my amazon with the saturn engine does alot better than that. (but the b20 is alot more fun that the saturn 1.6l

When I bought my 140 it had a stock exhaust. It broke 18months later and I left it off (no muffler, exit just before where the front muffler should've been) for 6 weeks and the fuel savings I got paid for a brand new 2" free flow system.

I gained 50mi to each tankfull!!!!!!!!!
but most driving was at freeway speeds at the time so the revs were in the 4000rpm range alot
--
Alex Shevlin (Sydney): '72 144S, '81 244GLE, '81 244GL, '01 V70XC

I thought SU's called for ATF fluid.
--
90 744ti, airbox, K/N, manual boost, VDO, modified exhaust.

Bryan;

I believe they call for specific SU dashpot oil PNXXXXXX, costing who knows what, and who knows if that is even (reasonably) available in the US (internet search time!).

...it is critical to have light oil in the dashpot to slow and dampen dashpot movement, but its pretty noncritical what you fill it with (watch some SU specialist come and beat me up on this)...the oil does get slowly consumed, and so needs to be replenished periodically... the important thing is the weight/viscocity... ATF fits the bill nicely, so does Marvel mystery oil and probably Vitaloni's Extra Virgin Olive in a pinch!

Cheers

Sorry Ron, but like "extra money" there is no such thing as an extra anything else in life. Olive oil might work in Webers if they had ever discovered Skinner Union, but here in Canada ATF is the best (cheapest) all year oil for SU's. I would rather tweak the settings seasonally than try to figure out the best oil for the season. Anyone in a varying climate who drives all year should invest in the "hot air" box and air cleaner.
We sold that as an accessory in 1970 to older Volvo owners-and you only have to buy one air filter.

Hello Bob! A good, correctly adjusted 122 should reach theese figures with out much problem, however the twin carb engines use a bit more.
I had a -66 122 about 10 years ago (downdraft zenith) it used about 8 litres/100 kilometers at highway, without O.D.

D.E.Sweden.