I ran a cross a good phrase in a link to Weber carbs: "The natural enemy of the Weber is a novice with a screwdriver."

 

Here's a little more context for anybody that is interested in this project. I have a 1967 1800S with a B20 engine that has some mild mods. I rebuilt it a couple of years ago and it is running well with stock SU HS6 carbs. It is bored .030 over. It has an F head (I thought it was a E, but was confused - it is an "early" F), so it has the larger intake valves but hasn't been ported or anything. It has an IPD street performance cam and slightly lightened flywheel, well balanced , but it's otherwise stock. Stock 4-into-2 cast iron exhaust manifold and 2-into-1 down pipe. Stock 1 and 3/4" exhaust. Calculated static compression 9.3:1.

 

What I have been able to find out so far is that these two Weber 45 carbs are what is known as a type 9 and a type 15. Supposedly, the bodies are the same but they came from the factory with different specs on practically everything that can be changed - jets, chokes, needles, venturis, emulsion tubes, and several other things I have never even heard of. No wonder Webers have a reputation for being very complex to tune. However, I guess that is why they are so tunable to get the most out of an engine. I have a huge learning curve ahead.

I haven't taken the carbs apart yet, but I expect they have been rebuilt in the past so maybe all those variable parts have been made to match. Whatever, I'll make them match and tune them to my engine or at least try me best to do that. I can always go back to my good SU HS6 pair.

 

PROBABLY more about that Manifold & Breathing so Porting Intake Manifold and Nice 3-4 Grind on SS Valves would Go just far as Weber's . .
( I able to Remember someone Trying Mikuni Sliders ) seems even Weber Intake had to be Ported some to Match . .

Really Nice Find Thou . . Look to be Tuned for 3.0 L Austin Healey ~ Parts $$$ as Weber is Making Carbs Again . . to Classic Sports Car Owner
$ $ $ $ . .

Hey Found a Great Link for Comparisons & some Info on Weber's ~ CARBURETORS

 

My only words of advise

I currently have a nice pair of SU HS6 carbs that are working quite well,

Be cautious about turning a car that is 'working quite well' into one that is 'not working quite well'. There may be a reason why those Webers were in a box and not on a car.

 

My only words of advise



Be cautious about turning a car that is 'working quite well' into one that is 'not working quite well'. There may be a reason why those Webers were in a box and not on a car.

Ha! Good point - if it ain't broke, don't fix it. If this was my daily car instead of a pure hobby car, I wouldn't mess with it. However, the side draft Weber 45 DCOE carbs are pretty appealing to give it a shot and they sort of fell into my lap for not much money. I will keep my SU HS6 carbs, so I can easily go back to them if I get tired of trying to get the Webers tuned. The carbs were connected with a fuel line and had the manifolds to match a B20, so I think they were already installed on a B20 as a pair. BTW, I also scored a B20 with an E head that had been converted to carbs, probably the very engine that these were installed on.

First step I'm planning on is to disassemble the carbs and check all the variables (jet size, etc.) to see if they seem reasonable for my B20 engine, based on some of the configuration guidelines I hope to find. I'm open to suggestion as far as configuration guides (books or links or whatever) or even specific configs that work with anybody's B20. At least that might be a good starting point. I plan to install a broad band AF and baseline my SU carbs, just out of curiosity, because I will want AF to tune the Webers. I'll probably just seat of my pants feel too, dyno runs are expensive, and I'm not building a rally engine here, I'm just putzing around really.

I did take the manifold off one of the carbs. The throat looks good, no scoring or ridge from the throttle plate. I was surprised to see two progression holes instead of three. That would be hard to change, beyond my capacity, but a pro shop can do it.

I'm already having fun!

 

Link I Provided Not Only Provides Carbs , but Tunes then for You - on a - Dyno . .
ALSO:
Their Mikuni Set Up's are Winning in Many Circles just do to ~ Improved ~ Drive_ability & 15hp ..

 

@EngTech Interesting info on link to Vintage Performance. I've heard that one should be wary of buying anything from John Parker, although I have no direct experience. Some people have had good experiences and are happy, some have not.

 

My advice is to stay away from J Parker. I personally contributed about $800 to his winter holiday fund for some vapour-ware Bilstein shocks and springs. A lot of the products that he showed on his pages were always 'in production' or on back-order with delivery to be scheduled in a couple of months (just long enough to allow the window for non delivery in the PayPal dispute mechanism to expire). The customers who are satisfied with him are probably the customers who can go into his shop and demand in-person delivery.

 

OK Charles

I always Use Master Card - It Never Runs Out on Time !

Even Blocked E-bay about Dispute that was 110 Days Old , E-bay was Pissed Oh Well
What Goes around Comes Around - Finally Paid Me when I Pulled Rug !


Anyhow Mikuni's are Easy Set Up and Massive amount of Support My MG Turned 7000 Rpm's
for Years & Years

 

Yes, if I was just looking to upgrade carbs I'd look into Mikuni; but I've got these Webers and they are pretty cool.

 

Agree those are Classic's would a Coffee House Talk of Town . .

 

Carbs bigger than the engine can benefit from are a waste. SU carbs can handle your engine as described and more.

 

True, I can't dispute that the 45 mm DCOE carbs are overkill for a close to stock B20. How much displacement and other engine mods do you think would be appropriate to employ the twin DCOE 45 carbs? I'm thinking along the lines of building a torque oriented street performance B20, not a race engine.

 

I was always under Influence that Weber's had 3 Jets - Not sure Why -Anyhow - I'm probably thinking of Emulsion Tube .. instead of Jet ..
I Know Carbs that have Mid Range Jet can give Better MPG & Drive_ability . . By using Mid Range Jet more ..

Our Old Mazda with 2 Barrel was Running like Pig - I just Drilled out Low Speed Jet - from .036 to .048 and Way Better Driving & Better MPG . .
As High Speed Jet just wasn't being Called into Action - unless - Floored . . 2 Barrel

Carbs on MG - Mostly just Setting up SYNC Between 2 and Topping Up Dash Pots .. & Velocity Stacks . . Helped ..


Either Way that's a Lot Carb for B20 - smaller on Float Valve Seat & Needle Valve Smaller on Emulsion Tube & Smaller Air Jet . .

You probably looking at Over Bored Over & Stroker Kit get to 2.3L with Head Work & Cam . .
Volvo

 

I found an exploded parts diagram that lists 4 jets: air corrector jet, idling jet, main jet, pump jet. The thing I was surprised by was the progression holes in the top of the throat that are uncovered by the initial and progressive opening of the throttle plate. The video I was looking at talked about 3 holes and the carb I have that I looked at only has 2 that I was able to see. I just had a quick look, haven't had time to spend on it yet.

WEBER 45 DCOE early parts diagram

Interactive exploded view with part numbers and prices

www.carb.parts

 

Guys;

My beloved SUs do 95% (if not 100%, one might argue!) of that with just 50 parts! ...and to get those last 5%, Weber has to double the parts...I know what I'd prefer...just saying...!

 

There is a lot to be said for a good pair of SU's, no doubt. A DCOE has about 100 uniquely numbered parts, for many of them there are 2 or more.

 

The best thing inside the box are those intake manifolds - they appear to be original VCS [Volvo Competition Service] intake manifolds as fitted to the Stage 3 and 4 kits, fitted with Solex DDH or ADDHE carbs. Those manifolds are rare and highly desired. That's a great score.

Re: carb differences between type 9 and 15: short answer: don't try to make them work together.

Longer answer: the throttle plates are different. You can get either type to work well on a B20 (even one like yours, which really doesn't need these carbs) but the two types won't ever match one another. You might also have different progression holes between the two, which is just going to make things more difficult - these are complicated things to explain, but they have to do with off idle progression, and what you'll end up with - best case - is an engine in which 2 cylinders transition off idle nicely while the other two do not.

It's also possible that the carbs are identical but that the top cover on one has been replaced. That won't hurt anything, but it'll keep everyone confused.

Other difference is really just jetting, which is easy to change but difficult to get right and expensive. If you need different emulsion tubes, for example, that's about a hundred bucks for all 4. And if you buy some that aren't right, you get to spend another hundred bucks on the next experiment. Main jets are around $10 each with shipping, same for air correctors, chokes $30 each, aux venturis $I forget, idle jets $8 or so and accelerator pump jets and discharge valves. All of this is to say that just to baseline the carbs and set them up so that they'll be close for your engine can easily cost hundreds of dollars; and once that's done, you can start tuning, which means buying more jets. Also get rebuild kits, and new softmounts. The alternative would be to hire someone who has a full array of jets to set them up for you. The upside is that you don't buy so much stuff that you'll never need; the downside is that those guys aren't cheap and you don't get to learn anything along the way.

Once they're on the engine and working as designed, they're really great carbs. If you want to run them, by all means go for it. But they're complicated and can be profoundly frustrating. A pair of SUs will feed a B20 up to around 150HP, which is a higher goal than most of us would like to admit.

Re: jetting: for the engine you describe, start with something like:

34mm chokes
4.5 aux venturis
135 main jets
F16 emulsion tubes
185 air correctors
50f8 idle jets

Don't worry about the accelerator pump jets for now, but at least confirm that they match; and replace the aluminum seal washer EVERY TIME you remove them.

First thing, though, if you're going to try DCOEs: start with a matched pair. It'll never run right otherwise. This is critical.

If you ever want to sell those intake manifolds, I'd offer top dollar.

Cam

Cameron
swedishrelics.com

 

Re: carb differences between type 9 and 15: short answer: don't try to make them work together.

I am thinking perhaps that is why they are sitting in a box rather than attached to an engine .

 

Hey Cam,

Thanks for the info. Great stuff. I'm away from home right now, but over the next few days I will try to spend a little time looking more closely at the carbs. How would I determine if the bodies actually match - other than the covers having different type and number stamps? I thought I saw someplace that 9 and 15 types are the same other than the stuff that is installed in them (jets, venturis, etc.) If I want to play with the Webers, I guess I'll have to find somebody with a similarly mismatched pair and swap them out so we both end up with matched pairs.

I remember seeing some numbers cast in the manifolds, on the bottom side. I'll check that when I get home.

Given that my B20 is running fine on the SU HS6 carbs and the DCOE carbs would be overkill, maybe I should hold off on this possibly fools errand - at least for now. Actually, this has started me pipe dreaming about building a street performance B20. I have what is perhaps a good core: a B20 (six bolt crank) with an E head. Again, I don't know anything about the engine other than it can be turned over by hand. I should start a thread on the Pushrod Performance Forum.

 

Just seems Odd those were in Same Box _ Together . . Might be some Tricks A Foot Inside .. those Carbs

 

Yeah seem what I was Thinking , after the Description - Folks back then Knew what They were Doing & Stored , so Yeah They Tricked Carbs - just
have Folks Scratching Heads , saying Dam that Thing Runs Great & How'd get Those Carbs to Run so Good together ..🤩

 

I took the manifold off the other carb and the air cleaners off both. With a quick look around I didn't find any markings on the carb bodies, but I haven't taken them apart and cleaned them yet. I did confirm that both bodies have 2 progression holes in each throat and they look to me like they are in the same place and the same size (just eye balling them) on both carbs. All the throttle plates are marked 78 degrees. [Edit: I initially thought it was the chokes with 38 stamped in, then I thought it was the auxiliary venturis; but after studying the exploded parts diagram and looking again at the carbs in a better light I am pretty sure that it is the chokes that have the number 38 cast (molded?) into them.] That's about all I can see at this point. I didn't spot any differences in the carb body castings, but I don't really know about them. Is there some way to confirm what the bodies are, or is it just what is stamped on the covers?

I didn't find any markings on the manifolds other than the numbers cast on the bottoms:419883 & 419884. [Edit: I found the intake manifolds for side draft carbs in the Volvo R Sport catalog with part numbers 419883-4 and 419884-2 that look just like the ones on my bench as far as I can tell.]

 

38 are way too big for that engine, and assuming that whoever ran them before jetted the carbs appropriately for their applcation, my guess is that the jets will all be more aggressive than what you'll need. They're easty to remove. When you have a chance, take them out and let us know what you have.

Cam

 

Thanks, Cam. I greatly value your input here. I don't know the history of these carbs or the B20E engine. It will be interesting doing the disassembly. Both the carbs and the engine have been run and will need cleaning and who knows how much refurbishment, or even if they are actually rebuildable. I don't actually know if the carbs were installed on the engine or tuned to it. I got them both from the same source, but the previous owner passed away and I got them from the estate with zero information.

I'll be back with more info when I get a chance to do some disassembly.

 

Could be the reason. My question is this: Is there any difference in the cast aluminum body and cover between type 9 and type 15? If everything that can be changed for tuning (jets, chokes, venturis, etc.) matches, is there any difference?

[Edit: I sent email queries to Redline Weber Division and Worldpac (a Weber wholesale distributor) to see what they say.]

Update: I just got off the phone with a friendly guy in the tech support of Worldpac. He told me that the castings are the same, but the progression holes might be drilled in differently. He suggested mounting them on the engine and hooking up the linkage, then shining lights in the throat and operating the throttle linkage to see if the corresponding holes in both carbs are uncovered at the same time.

 

Again, the differences are in the throttle plates and progression holes. If your throttle plates are identical between the two, and the progression holes are exactly the same it's likely that someone swapped a top cover on one of the carbs.

One other thing to check but I don't know that it would give useful insight: idle mix screws. Early carbs had coarse threads, later carbs had fine threads. Hopefully yours all match here too.

Cam
Portland