Carburetor Help

[CincinnatiE9]

Sorry for two topics so quick but they are very different and I think they warrant two threads until I get a build thread going.

I bought these off the guy who sold me my motor, he claimed they were weber carbs and my car stock has zeniths. He said these are better and may make my car perform a little better. They look very similar to pictures of stock carbs I've seen online. I only have $100 in them, so if they are just stockers, I'll keep them as spares.

Plugged EGR?

Am I missing something here?

Thanks, Paul.

 

[Tierfreund]

That sure ain´t no zenith (stock) carbs...

 

[OCCoupe]

They look like webers to me. The accelerator pump and the choke mechanism look identical to mine.

 

[m_thompson]

That is the same Weber 32/36 DGAV setup that I have on my 3.0CS. It came from JAM Engineering. http://www.jameng.com $895.00 new. I probably have the installation manual.

Be really careful about adjusting the throttle linkage. It is easy to get it adjusted so that it will go overcenter and lock wide open. The secondary throttles are mechanical and require a really heavy push to get them open.

 

[CincinnatiE9]

Should I use them over my Zeniths?

 

[OCCoupe]

It's all a matter of opinion. If they are 38/38's which they might be then I think most would agree they are better; but you really need to take them to an expert to make sure the shafts aren't worn, if they are then you would be wasting your time on them. You also need to ask yourself if you are going to stay 100% stock.

 

[CincinnatiE9]

I am not staying 100% stock. The numbers matching motor is destroyed, the car is worth, what? $15k restored? I want to put under 10k in it and drive it. Eventually I'd like to pursue a 3.5L block, Shrick Cam, Bavarian Auto header, maybe some port work. For the time being it will be stock, maybe the Bavarian auto go fast plug wires (because they are cheaper than oem, and red!) and the webers. Car has some aftermarket wheels on it. Bavarian Auto Sells rebuilt kits for them, so I will rebuild them if I decide to use them.

I have 3 sets of carbs,
-whatever is on the car now (have not popped the hood)
-whatever is on my new motor (not here yet)
-these webers

 

[acat2002]

Just my $.02, but I wouldn't care if the block or head was original to the car. I don't get the sense that "the market" cares either. Block, head and most mechanicals are afterthoughts in the E9 scope.

Condition of the body and originality of the interior I think drives the value more.

@Group - Does anyone out there know why the trend back in the '70s was to replace the Zeniths with Webers? was it a gas milage issue? performance or reliabliity issue? I have Webers, but I hear a lot of people squawking about Webers and want to go back to Zeniths.

 

[MichaelP]

People who buy coupes to drive them because they're fun and pretty to look at don't care much about matching numbers. Collectors, or the folks who own these cars as expensive trophies get worked up about matching numbers. At this point, fortunately, they seem to be attracted only to CSLs.

Weber DGAVs were a 1970s-80s lazy mechanic's cure-all for customers who kept returning to their shop with Zeniths that kept sliding out of tune. With both water and electric choke, INATs are more difficult to tune properly than DGAVs. Once the word got around to various shops that they could drop the burden of not having to find out how to correctly set Zeniths on the customer - by convincing them to sink a grands' worth of parts and labor into new Webers - it became 'common knowledge' among coupe owners that Webers were SOP.

The sad part is that many coupe owners thought this was fine - at least the ones who just puttered around in their coupes and never cranked opened the taps. The DGAV (32/36 progressive) doesn't allow enough air into the pump (the engine) to allow it to operate to its full potential as the 35/40 progressive INAT does. I've had coupes with both Zeniths and Weber DGAVs and at WOT the difference feels like 50 horsepower.

 

[gwittman]

I bought the JAM Engineering Weber set up for my 2800 CS in the mid 80s because my Zeniths needed to be rebuilt. I came across a really good deal on the Webers which included installation. I was told I would get better performance so I decide to shelve the Zeniths.

I have been very happy that I had the Webers installed. The stock air cleaner fits on them well and everything remains stock except the carburetors. As mentioned above you have to watch out for cam-over with the linkage. I was surprised by that one time. I am very confident the performance is better with the Webers but then again I am comparing that to worn Zeniths.

Another thing you need to consider is the manual secondaries. If you floor it when the engine is at low rpm, you can bog the engine a little. That is a little too much carburetor at low rpm. I don't even notice it anymore because I have learned instinctively not to open the secondaries at low rpm. The mechanical secondaries are also a good thing because you can open them earlier than the vacuum secondaries will. I imagine the Zeniths could be tuned to open earlier also. I have never noticed it being hard to open the secondaries.

 

[jhjacobs]

These are definitely webers and to be honest they look pretty scruffy. They will need a thorough cleaning an lubrication to make the action smooth.

Before you consider pulling out your Zeniths to install these Webers you need to know that the weber linkage is probably needed. Also, the weber air cleaner mount holes are about one inch closer to the firewall so you will need to drill new holes in the air cleaner shroud to mount it.

I am pulling my working set of webers this weekend to re-install Zeniths. If you need some weber parts (I have some "parts" webers) or the relatively clean working pair I'm pulling shoot me a PM. Due to the generosity of various board members I also have plenty of spare Zeniths (at least 4 pair now).

 

[CincinnatiE9]

Well the car is months from running, we'll cross that bridge when I get to it.

My point about the numbers matching is, it does not matter to me. So that's why I will consider modifications along the way, I would like to drive the car, not look at it, the coupe is such a pretty car. I have a fantasy of driving it down Pacific Coast Highway someday in some 70s movie fantasy haha. I drove PCH earlier this year in an Infiniti, fun, but windows down in a 70s sports car... excuse me for a moment. That may sound stupid to some of you, but its always sounded cool to me. Top Gear watchers, be reminded of the Ferrari Daytona 365/4 on the French Riviera.

I don't look at my cars, I drive them. So if I can improve them, I will. I am actually considering the 5speed upgrade to get some respectable highway economy. What cars 5speeds bolt in? Or are the easiest? I know nothing about the swap.

 

[bert35csi]

I am actually considering the 5speed upgrade to get some respectable highway economy. What cars 5speeds bolt in? Or are the easiest? I know nothing about the swap.

Read all about the 5 speed conversion here, http://bmwcsregistry.org/Technical/Five_speed_upgrade.html written by the coupe guru, Carl Nelson.

 

[CincinnatiE9]

So it sounds like I need a 528 donor car haha. I'll have to think about it, I have two getrag 4speeds, I was hoping I could sell one to buy a 5speed, sounds like I was wrong.

The car has rebuilt carbs on it, how recent, I don't know, I found a speeding ticket from 88 in the glovebox haha.

 

[MichaelP]

The Getrag 265 or 262/5 is available from a pretty good range of donors: e12 (as mentioned), early e23s, early e24s, 1985 e28 and the e30 M3. They are getting a little harder to find in good shape, but I wouldn't call them scarce yet.

 

[CincinnatiE9]

Looking at local u-pull-its inventory:

Bmw 3 series 1985
Bmw 3 series 1987 325
Bmw 5 series 1982 528e
Bmw 5 series 1991 525i
Bmw 7 series 1985 735i
Bmw 7 series 1989 735i

Any of those do it? I don't have the money as of present. Is a Getrag 4speed 3.0CS trans worth much? I have 2, wanted to sell one to fund the 5 speed swap.

 

[lip277]

The thing with later cars (from a donor standpoint) is the transmission is missing the drive gears for the speedo... Earlier cars had them.

I am in that situation myself.
I have a transmission from an E30 M3 (came with the car - right now it is sitting on the garage floor).
I need to get the drive gear bits and all done to convert it to the mechanical speedo.
And - to tell you the truth - I have not done much in that regard.

Other fish to fry - and (compared to the 2002 I have) - sure does not 'need' the 5'th gear like that car. But - I will install it eventually.

 

['69 2800cs]

and (compared to the 2002 I have) - sure does not 'need' the 5'th gear like that car

I had the same observation with both cars. Thankfully I have a 5 speed in the CS but really could get by without it. In an 02, it's pretty painful with the 4 speed.

 

[CincinnatiE9]

Does the 5speed give a significant fuel economy increase? Honestly that's the only reason I care. I would like to drive this car, a lot. Not looking for performance increases, just wanted 20mpg or above (I was told CS's do around 18?). I know I said I kicked around the modded 3.5 but for the time being I'd like to just have a car that gets enough mpg that I won't go totally broke driving it.

I was just offered a FREE! 533i... its an auto... bummer.

 

[jhjacobs]

I can't be sure about the the fuel savings with a 5 speed but it seems reasonable. I have a Getrag 265 5 speed and around town I get 17-19 but 18mpg but on the highway I get 26-27. My E3 with a 4 speed never got above 24mpg but the CS is a bit lighter, more streamlined, and I have weber 34/38's. I also tend to be a tamer driver these days. However, I tend to attribute my good fuel economy strictly to my shift knob. :twisted: