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I recently went through this same decision making process, but with one more variable - Solex, Weber DCD, or Weber DGV. After trolling through the 750/101 board and talking to some smart people I decided on the DCD. Here's my take on the pros / cons of each.

DGV:
Pro - more power, relatively inexpensive, easily available, lots of sources for parts
Con - a bit too modern looking, probably OK for a 1300 but somewhat tall for a 1600, need to use an ugly aftermarket air cleaner

DCD:
Pro - more power, period correct, tuning parts still available, can be used with the OEM air cleaner (with a hard to find adapter)
Con - hard to find used, expensive new, a bit taller than stock but not as bad as a DGV. With the adapter it's about 3/4" taller than the original 1300 Solex.

Solex:
Pro - original, no fitment issues, good MPG when running well
Con - 50+ years of frustration getting these to run well, tuning parts are NLA, down on power compared to the Webers

I'm sure others will chime in with their input. Here's a pic of my DCD, along with some other goodies for the new engine.

-Jason
 

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hi - and for what its worth, i would do neither (thought the pros and cons are well argued). certain that solex has to go but, instead of webber (who for some reason at the time, probably due to personal friendships with mr. e. ferrari, snitched all the good press) seriously think about del' ortos. completely the db's, and dont need retuning every 8k miles, and dont swallow o rings,and dont wear on the spindles as they have roller/ball beaings,and look sexier,and give up to 15% more power over comparible webber,and more exclusive. hope this helps!!!
 

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I too prefer the DCD on my 101.23 Spider.
It has Veloce cams and is a huge improvement over the Solex.
The trick is to find one of this model.......
Solves most of the height problems.
There was one on ebay.it last year.
 

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SOLEX per sempre!

I may be swimming against the current here ... but
I choose a SOLEX for the aforementioned reasons:
It's original equipment for a Normale
It fits properly to linkage, air filter and beneath the bonnet/hood
They perform just fine for me

Regarding parts ... I have 'em. If I can't find something in my STUFF, I make it.
Mods can be made for more performance from a SOLEX carb body ... if needed.
Personally, I've never had to fool much with a clean carburetor once it was fitted to an engine ... I wish I could say the same for ignition parts.

I may be biased because I refurbish SOLEX carbs. Not knowing any better, I've done this for more than 40 years.
Here's a before and after pic of a recent rebuild:
 

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I rather stubbornly stuck with Solex as well.

Parts are being reproduced for German Solexes. I took my Solex to a local shop specializing in older German cars and we were able to find most of the tuning jets in their parts bins.

Why would a Weber make more power? Is the out-of-the-box jetting superior?

Mike R
 

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GTD,
I would be interested in getting the origional Solex for my 750b refurbished, do you do this for hire?
Can someone confirm, Giulietta normales had a fuel starvation problem when cornering (to the right?) that was cured by drilling between the float chamber and an adjacent cavity.
Brad, Escondido, Ca
750b, 750f
 

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Solex to Weber

I have a Weber DCD on my Giulietta Spider 1960 with a taller 1600 cc engine.
So, even with the adapter from Pierce Manifold it was a tight fit.
My solution was to shave off some height off the top of the intake manifold carb mounting surface. How much? That depends on the thickness of the specific intake manifold.

If you take too much off , your into the water jacket so this has to be done carefully.

Final setup works well. The stock air filter tie down flange as an added bonus fits flush to the cam-cover boss.

The Solex that fits on the Giulia 1600 cc engine is a far better carb. than it's predecessor. No fuel starvation issues with cornering.

I can post a picture of the intake manifold if needed.
 

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I use a 36 DCD as well. Just perfect in my opinion. Did some of you also increased the intake manifold from the original 28 mm to 36 mm? Any trouble with machining the manifold?
 

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Find a manifold that is already had two twin 36mm openings.
My spare one has the above dementions
I probably would xray the manifold to see where the water jacket approaches the top of the mounting flange/ boss and intake openings.
For those who may not know, the intake manifold is a superb piece of casting with a inner water jacket just underneath the mounting flange.
 

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I use a 36 DCD and it has noticeably more torque than the Solex 35 APAIG.

Not withstanding refurbishing (not just rebuilding) the Solex, the real problem with them is that the spindle bores wear oval, leaking air. This makes tuning them an exercise in futility. Unless/until the air leak is cured, it will never run properly.

This accounts for the almost universal frustration among Solex owners.
 

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proper DGV jetting?

Can anyone point me to a listing for the proper jetting for a DGV for a 750 normale? I have done some searching around without luck. Ok, I know it's also a matter of opinion, but I need something as reference.

While we are at it, the DGV came to me on the car and I think that the linkage was such that the secondaries never opened. I have done some fussing and I can now get some action on the secondaries, but I think that give me A LOT of fuel into the engine. Black smoke would be my clue.:mad: The previous owner made a mess of just about everything on this car. So, I am suspecting that there is some ridiculous jetting on that side, and he just avoided the issue by never opening that side....:rolleyes:

Thanks,
Jon
 

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Add my name to the list of Solex users whose carb works great except for a couple of annoying habits- it bogs down momentarily when accelerating from idle (faulty accelerator jet/diaphragm?). Also, it nearly stalls when coming down through the gears to idle unless I add throttle to keep the revs up. And thirdly, it exhibits the fuel starvation Brad mentions in hard right-hand cornering. Throttle response is great otherwise. It really has good power even from low revs. Can anybody pinpoint some fixes for these problems? GTD- I would be interested if you have dealt with any of these problems before and if you offer rebuild services.
Phil
 

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Phil
Let me answer the last question first; I completely refurbish SOLEX carbs, this entails more than "throwing in a kit and calling it rebuilt". However; this is a hobby - not a full time business.

The bog-down or hesitation you describe is a classic description of transition circuit problems ... using a strong light, peer down the primary venturi to the throttle plate in the base section. On the RIGHT side of the bore look for two tiny holes in the wall, just at the level of the closed throttle plate. One hole is for the vacuum supply to the distributor, the other is the outlet for the transition or progression circuit.

It's likely your problem lies here ... but I won't attempt to resolve it on this forum. (Please don't attempt to poke at these holes with a wire or awl :eek:)

Regarding the Right-turn / fuel starvation ... I will simply say that the cure is in an accurate fuel level setting. Drilling holes or breaking and removing the sediment baffles is not a fix. ;)
SOLEX designed their fuel inlet valve and float in a manner different than other carburetor makers. The float arm is never bent to adjust fuel level. Instead, washers of different thicknesses are inserted between the float chamber cover and the fuel inlet valve. Another variation is that each carburetor application calls for a different weight of float.
 

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Wow, thanks GTD, that really helped to start the troubleshooting process. One question begets another, but I'll use the PM forum from here on out. Your info should be useful to others when making the decision to scrap or stay with the ol' Solexes.

Phil
 

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Add my name to the list of Solex users whose carb works great except for a couple of annoying habits- it bogs down momentarily when accelerating from idle (faulty accelerator jet/diaphragm?).
A faulty diaphragm would pump little or no fuel. My car had a rich bog which was cured with a smaller acceleration pump jet.

Mike R
 

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I,too, am planning to use the Weber, but am curious if it was a valid carb at build time (1959). I always hear that it is "period correct", but did Alfa actually ship 1300s with a single down draft carb?
 

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I,too, am planning to use the Weber, but am curious if it was a valid carb at build time (1959). I always hear that it is "period correct", but did Alfa actually ship 1300s with a single down draft carb?
Bob, if you're asking whether Alfa ever shipped a 750/101/105 car with a single downdraft Weber carb, I'm pretty sure the answer is no. DCDs came on Fiats and Cortinas, but no Alfas out of the factory.

-Jason
 
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