[justcharlie]

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.

 

[EngTech]

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

 

[justcharlie]

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.]

 

[volvorelix]

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

 

[justcharlie]

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.

 

[142 Guy]

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 .

 

[justcharlie]

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.

 

[volvorelix]

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

 

[justcharlie]

I had a look at the idle mix screws. The threads on the screws from both carbs are the same and the screws are tapered and pointed at the tip, identical as far as I can tell. I pulled the progression hole covers and the holes look the same to my eye, which is encouraging; but I won't have time in the next week so so to mount the carbs and do the light test that the guy from Worldpac suggested to verify hole placement. The only way I can think of to verify that the holes are matched size is to get some small drill bits and use the butt end (gently!) to find the ones that fit the holes. The holes are really small.

 

[justcharlie]

I thought of a good way to test the diameters of the progression holes. I took a sewing needle, very gradual taper near the point, that would go about 1/4" into the progression holes - gently resting in the hole. I used a dial caliper to measure the length of the needle remaining outside the hole. They matched exactly between the two carbs. So while I don't know the diameters, I do know that they are the same for both carbs.

All of the throttle plates are marked 78 degrees, so that's also a match.

So far, so good.

When I get time, I'll do the light test to see if they get uncovered at the same time.

 

[EngTech]

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 ..🤩