Before you practice shotput with your old carbs...
Did you take the top off the carbs,and check if the rubber diaphram is intact?
--
71-145-S

Joe,

I, too, own a 1970 142S. I recently converted from a Weber DGV to a set of twin HS6 SU carbs. I bought the SUs from Jeff Palya of Paltech Micropolishing. You can simply Google him. For $550, Jeff built me a set of rebuilt carbs that looked brand new. I could not be happier.

As to the difference in performance, let's just say that it is night and day. The SU delivers far better acceleration than the Weber. They are easier to start when hot; and with dual chokes, they start with minimal cranking in cold temperatures. Yes, the Weber is less expensive and yes they have accelerator pumps. However, Volvo designed the 140 series to run on SU carbs. They resorted to Stromberg when the SU plant went on strike in 1969. Learning how to use a Unisyn is simple and keeping the SUs in tune is not that difficult. Yes, they are subject to wear. But that alone should not dissuade you in my opinion. EVERYTHING on the car is subject to wear. The idea is to buy quality parts that last.

Now hard as this may be to believe, Jeff Palya is convinced that Strombergs can be rebuilt and tuned to run stronger and smoother than SUs. Yes, they are smoother at idle, but I am not in any way convinced that they deliver better performance. You might talk with him about this. I owned a '69 144 with a pair of Strombergs and found the performance anemic at best. Besides, they require a special allen wrench tool to adjust the mixture.

A new Weber set-up is around $550. For an extra hundred or so, you can get a solid SU set-up (including manifold and air filters). In my opinion, this is the best way to go. Best of luck!

My take:
Strombergs are unuseable, though I got my '70 145 through CA smog with 'em (AAARGGGHHH!).
SUs are marginal junk, at best, though if you can stop the air leaks around the throttle shafts, you're way ahead.
Weber DGV series are cheap garbage, some of which (DGV, not DGAV or DGEV) may be made to work, if you're lucky. I'm lucky; I've got one that works quite well (not on a car, at this moment).
Properly tuned, properly sized (small) DCOEs FTW.
Mikunis, Dell'Ortos, etc may be better.
I hope I've brought some cheer to your life.

You might try a rebuild kit on the Strombergs before throwing in the towel. They are almost universally unloved, but they aren't totally worthless. In your case, it may just be a case of a leaking needle valve that lets residual pressure from the fuel pump overflow the bowls and put raw gas in the manifold.

But if they are not worth messing with, here's my opinion on the replacements:

Conclusion up front - if you don't care to read the reasoning: Get a nice pair of HIF6's.

1) Weber DGV - Needs a special manifold. This is a barely adequate replacement (in terms of performance) for a bone stock motor. Like most Weber's, it really doesn't have many adjustments, all tuning must be accomplished via swapping jets. Which isn't a simple task even if you have a kit full of different air correction jects, main jets, idle jets, pump jets. Which you likely don't. Which likely means you'll just bolt it on and live with whatever state of tune it came to you in.

2) SU's - The use the same manifold as the Strombergs. But they are just better built, better designed carbs. Not sure why the Stromberg ever came into being, since they are basically badly cloned SU's. HIF6's are the more modern variety, and were fitted on many B20 140's, not sure of the rhyme or reason to which models had Strombergs vs. SU's. They are slightly more difficult to tweak than the older HS6's (what was on most B18's) and flow slightly better (I've heard). Main problem with SU's is throttle shaft wear, bronze shafts turning directly in drilled holes in the alloy body - eventually it jsut wears away the alloy and lets air through at idle, and the unmetered air stymies the typical tuning method which sets the mixture properly at idle. But get a rebushed set, or an unworn set, and these are great carbs.

3) Weber DCOE's - Almost always installed in pairs on a B18/20. Needs a special manifold. This is a high performance option. They are really not worth bolting onto a stock motor. Like the DGV's, they aren't really adjustable in many meaningful ways, mostly involve swapping little intricately machined brass bits, only this time, in sets of 4. I have a set on the PV's motor, and they tend to be snorty and thirsty, but man oh man do they scream with the pedal down. There is very little left stock on my motor though.

--
'63 PV544 rat rod, '93 Classic #1141 245 +t

John Parker @ http://www.v-performance.com/ has Mikuni carbs for B20's. Check it out!!

Hello,

Many members of the Brickboard community have kindly helped me in regards to SUs and Webers. My personal opinion and the general consensus is that a pair of properly rebuilt SU HS6 or HIF6 carbs are far superior to Webers in virtually all respects, especially if you plan on making performance modifications to your engine. Additionally, SU carbs have a vintage look and were original equipment on various years of the 140 series. Simple adjustments and perhaps a needle change (very simple) make for a quick install to your vehicle. The downside is cost. You really want to purchase a very good quality set of SUs for your vehicle. That means purchasing a used set in excellent condition, or preferably, buying a refurbished set. Rebuild kits are expensive, and if you get a "from a running vehicle" set from Ebay, you might very well get something so worn you can't possibly adjust it correctly. I did that twice :(

That said, right now I've got a Weber DGV 32\36. Why? Cost. For the price of a complete rebuild kit for the SU, I can get a very good condition Weber with manifold, air filter, and needles. Weber DGVs are perfectly acceptable in a stock engine if you can live with average performance and don't mind swapping several jets in an effort to get it "just right". Webers also require a separate header or exhaust manifold.

In conclusion, Weber DGVs are okay, SU HS models are better. DCOEs are high performance (racing) carbs.

Good luck!