Weber carburetor conversion kits.

[dj_efk]

As per my other thread re: Zenith INAT carb problems, the fallback option (very much not preferred) would be to investigate a Weber kit.

I see there are two kits available here in the UK (as I think there are in the US):

Kit 1: 32/36 DGAV

Kit 2: 38 DGAS

My question is this - I assume the DGAS is more for performance-modified engines, therefore for a mostly factory-standard 2800cs with uprated ignition and a very slightly warmer cam, for spirited road usage only, I should go with the 32/36 kits and expect very similar performance as to the standard / factory-fit carbs?

Anyone have any experience / insight?

 

[JFENG]

I can only speak to the Zenith and 38DGAS on E9’s. Here are my 2 pefnning on these carbs. Hope this is helpful.

(1) I think the average enthusiast can tune a properly rebuilt set of Zeniths. As discussed in the other thread, are your pair properly rebuilt? These were common on German cars of that era (Mercedes used a version), so expertise is surely avail.

(2) I installed a single 32/36 DGAV on a 2 liter 2002 to replace a very crusty emissions carb (1976 issue). It was easy to setup and get running acceptably. It ran rich but was reliable and performance was ok in all seasons (105F down to 0 degrees F).

(3) I have a pair of 38DGAS (tipo 4A2 per photo) on a stock E9 3 liter. It has been easy to tune and once tuned seems to run very nicely. I’ve spent perhaps 5 hours fiddling with them, dominated by the time required to access the jets (remove air cleaner, adapter plates, cold start linkage and carb top plates, change jets and reverse the steps). Had these been DCOE’s I would’ve needed but 1 hour to do 3 steps of tuning. I can’t compare them to Zeniths (due to a 35 year gap), but recommend the 38DGAS without reservation. I would go electric choke over coolant choke as the coolant lines get in the way of adjusting the various external screws. Also, the std cold start adj procedure caused my car to idle well over 2000rpm, resulting in a terrible startup rattle (before oil got everywhere). I bive this is really bad for wear and cylinder scuffing so I adjusted cold start idle down to 1600rpm.

 

[JFENG]

The zenith specific adapters at Webcon look very nice and appear to put the air cleaner in the proper position (eg not too far rearward).

 

[dj_efk]

Anyone else got any experience to share?

 

[jmackro]

for a mostly factory-standard 2800cs with uprated ignition and a very slightly warmer cam, for spirited road usage only, I should go with the 32/36 kits

With a 2.8 liter engine, a pair of 32/36's provide plenty of venturi area. Bigger carbs won't provide any additional benefit unless you regularly run at 7,000 rpm. You might want to read this page on the Redline Weber site: http://www.redlineweber.com/html/application_guide/making_the_right_choice_32.htm

I would go electric choke over coolant choke as the coolant lines get in the way of adjusting the various external screws.

32/36 carburetors are also available with cable-operated (e.g., manual) chokes. I have found these to be more trouble-free than the water or electronic versions. And I sort of like the ritual of pulling out the choke knob to start the car.

 

[JFENG]

Bavbob confirmed that Zeniths can be properly rebuilt (at home by an enthusiast) using info on this forum. The implication is a shop that actually cares about what they do should also be able to rebuild Zeniths correctly.

I’ve told you 38DGAS (or electric choke), can give you good performance on a stock 3liter (or 2.8) engine, are easily tuned, and retain the stock air cleaner. Same goes for the progressive 32/36 Weber.

So you now know that you have 2 options, OEM or Weber DGAS/DGVE, both of which are not difficult to tune and produce good resulted without the need for a rocket scientist.

Seems to me the only open issue is
Finding a shop that is the desire and competency to do the work. I recommend DIY.

On what aspects are you looking for more feedback?

 

[bill]

I had 32/36s on my '74 for a few years, always had to fiddle with the linkage to keep the idle set. Also, had to be careful not to depress the accelerator too far to avoid the linkage going "over-center" and getting stuck wide open. There may be a fix for this as I haven't seen too many complaints about that lately. I had no problems keeping them tuned otherwise.

 

[jmackro]

Also, had to be careful not to depress the accelerator too far to avoid the linkage going "over-center" and getting stuck wide open. There may be a fix for this

bill: Do you still have that condition on your '74? The car would be dangerous if the linkage could get stuck fully open. Thicker insulator blocks to raise the carburetors or even just a stop to limit the linkage before it reaches the over-center point are two possible solutions.

 

[Ohmess]

I had 32/36s on my '74 for a few years, always had to fiddle with the linkage to keep the idle set. Also, had to be careful not to depress the accelerator too far to avoid the linkage going "over-center" and getting stuck wide open. There may be a fix for this as I haven't seen too many complaints about that lately. I had no problems keeping them tuned otherwise.

I took the 32/36s off my car a couple of years ago, but whoever did the install removed the stop at the bell crank. I put this back in when I went to the triple Webers in order to ensure I wasn't stressing the throttle shafts when I push hard on the gas pedal.

I wonder if it was common to remove the bell crank stop when doing these installs? With this stop installed, I don't see how you could go over center.

 

[bill]

bill: Do you still have that condition on your '74? The car would be dangerous if the linkage could get stuck fully open. Thicker insulator blocks to raise the carburetors or even just a stop to limit the linkage before it reaches the over-center point are two possible solutions.

Thanks Jmackro...I drove the coupe for several years careful not to go over-center. I converted to D-jet FI several years ago, which worked very well, but lately I've had a no-start problem which I have always expected to happen with a 46 year old electronic system that few people know about and I'm at my wits end tring to diagnose.. I may rip it out and re-install the Webers, and if I do I will figure out some way to eliminate the over-center problem. Thanks again.

 

[Stevehose]

This happened to me on my first coupe back in the day, locked them open on the highway. Scared the crap out of me.

I had 32/36s on my '74 for a few years, always had to fiddle with the linkage to keep the idle set. Also, had to be careful not to depress the accelerator too far to avoid the linkage going "over-center" and getting stuck wide open. There may be a fix for this as I haven't seen too many complaints about that lately. I had no problems keeping them tuned otherwise.