190Sl Weber Installation

Hi All,

I just finished making all new throttle linkage for my 190sl and completed the installation of the new Weber 40DCOE carbs and filters. I fabricated the bellcrank and throttle push levels out of aluminum plate and installed needle roller bearings in the main throttle shaft and bellcrank. Got to love McMaster Carr online, where else could you have metric needle roller bearings in stock and shipped the same day?

The first picture is the installation close up, then one with the air filters, and lastly a picture of the car on the road.
Eric








[Edited by EricH on 12-01-2000 at 10:11 PM]

[MikeTangas]

Eric,

Your 190SL looks great!!! For your next pictur, get a friend to snap one of you tooling that stretch of road, we want to see the grin .

[Jim Villers]

Eric ... Great looking car and a nice clean installation. I especially liked your heat shields underneath the carburetors. It, however, appears that you did not cut a hole in the aluminum plate that holds the air filters for the fuel bowl vent. The purpose of this vent is to equalize the air pressure on the up-side of the venturi with the pressure in the fuel bowl. If these pressures are not equalized, it will greatly affect the fuel flow through the jets.

I discovered this the hard way; on a trip, I lost one of the jet covers from top of the carburetor. The engine experienced a severe miss under high power conditions; like going up a grade on the interstate. It took several days, hundreds of miles, and multiple parts (including plug wires) before a piece of duct tape solved it.

Jim Villers

[bstreep]

Jim, I think I see the holes he drilled. Also, when I was talking to a Weber expert about a year ago, he says that the cover over the jets doesn't even need to be in place, that it just keeps "junk" from getting into the carb...

Anyway, Eric, you might also want to make sure that your fuel pressure is correct for these carbs. I ended up needing to put a fuel pressure regulator on mine (about $50). I've also looked at replacing the air filter and silencer with filters. They don't look original, but it sure helps keep those carbs from bouncing around as much!

Bill Streep
'57 190SL

[Jim Villers]

Bill, you may be correct on the holes. They looked like bolt heads to me. On the need for the jet cover and the fuel bowl vent, your expert is incorrect. Not only have I experienced the problems of this condition, but a friend with Mercuni (sp.) carbs had the same experience when he bolted the original 190SL air horns (no vent hole) on his carburetors. My air horns have been modified to include the vent holes and I utilize the stock air filter.

Hi Bill and Jim,

There are vent holes just above the left air horn on each set. But I don't have a pressure regulator on there yet. What pressure should it be? 7psi? Where is a good place to get one?

Thanks,
Eric

[bstreep]

Eric,

The specs I have say 2-1/2 lbs. I got the regulator and all of the couplings I needed from a performance house. They got a kick out of the car... I THINK you've got the vents "plumbed" correctly, they are at the top left corner above the air horns.

Jim, I pulled the cover off of one of my carbs last night. It appears to me that any air under the cover over the vent is directly connected to the screw in jet cover. If the vent is open, so is the jet cover. As I said before, the guy I talked to at Pierce Manifolds spends every Friday, Saturday and Sunday at the track, doing nothing but tuning Webers. He's the one that told me that the cover is really just a dust cover, and designed to make the jets accessable. The other guys at Pierce tell me he has no equal in the US as far as Webers...

Bill Streep
'57 190SL

[Jim Villers]

Bill ... your observations of the air passages are correct. The issue is whether the air pressure at the opening of the venturi is the same as the air pressure outside of the carburetor. With no air cleaners, it should be the same. With a very efficient air cleaner, it would be close; with an air horn, hose and oil type air cleaner the differential would be greater. This thesis is relatively easy to test; cover almost the entire filter area of the filters with masking tape so that there is an air drag to get air into the carbs, drive the car at high power, 65MPH full throttle. Then remove a jet cover and repeat. With the jet cover off, it will run very rich, probably mis-fire, and trail black smoke from the exhaust. If continued, you will foul a plug. (I would have said drive uphill but my recollection is that your part of Texas is flat). If it didn't happen to me on my drive to Niagara Falls two years ago, I would not be so positive.

[Jim Villers]

Bill .... Eric's picture of his SL on a foggy road above Berkeley is one of the best I have seen. How about posting it on the 190SL Group web site. Eric, the site is familiar, I graduated from Berkeley in '65.

[bstreep]

Jim,

I'll snag a copy of Eric's picture, with his permission. I agree, VERY artistic. Also found this website, which I'll post on the Group website: http://members.tripod.lycos.nl/~ritzsite/190SL/01_190SL.htm

we should have a contest to see who can find any inaccuracies in the commentary.

As for the Webers... If I understand you and what I've seen under the cap correctly, the vent from the bowel exits to the left and above the horns. This same are moves through the top of the carb, fairly unimpeded, and to the jets that covered by the wing nut cover. Now, unless the jets draw in a fairly substantial amount of air, they would have the same access to outside air via the vent/bowl/passage as they would via a removed jet cover.

When I talked with Gran at Pierce about this a year or so ago, I had lost one of my covers and had called Piere about getting a cover as well as some other jets. He told me to go ahead and drive without the cover...

Now, tonight, I'm going to go out and drive the car. We live on the edge of the hill country, so it is very hilly here (our yard drops 55 feet from our back deck to the bottom of our yard). I'll first get it warmed up with the covers on, and tackle a hill or 2. Then I'll remove the covers and try it again. I'll let you know how it goes... I'm really hoping there IS a difference. One of the seals on one of the covers doesn't seat properly all of the time, and maybe if I replace it, the car will run better!! As you might remember, I've had problems with the car running a bit rich...

I also got a Crane ignition as you suggested. Unfortunately, mamma confiscated it as a Christmas present! I'll have to wait until after Xmas to install it...

Bill Streep
'57 190SL

[bstreep]

Jim,

Ran it up to temp going to pick my daughter up. Removed the caps, ran home, to the grocery store, down the back roads, and home. Ran like a champ...

Bill Streep
'57 190SL

[bstreep]

OK, I just made some new gaskets for the weber covers, and put them snuggly on the car. I drove all over town this afternoon and this evening. No detectable difference, with or without the covers...

Bill Streep

[bstreep]

Eric,

Can you email me your "foggy day" picture so I can post it on the 190SL Group website?

Thanks,
Bill Streep
bstreep@satx.rr.com
'57 190SL

Hi All,

I've been driving my 190 a lot since the installation of the new webers....its Great! You might recall that I had 42 dcoe's previously, and these new 40 dcoe's feel much peppier in the mid range. The new throttle linkage and bell crank also improved feel quite a bit!

If any of your 190s have a worn our throttle linkage (where the main connecting shaft goes through), I found out that the bronze bearings in the can be replaced with 12mm needle roller bearings from McMaster-Carr for about $5 each. The only trick is to increase the shaft tube ID with a drill that allows for a press in fit. The play in the main shaft was causing the front carb to open sooner than the back one.

Bill: I will send you the higher res picture which you can edit to suit.

Eric

[Jim Villers]

Eric ... I am VERY interested in refurbishing my linkage. I tried a replacement bronze bussing but could not machine it to fit. Please provide enough detail so I can order enough of the correct parts. Also please email me a copy of you picture in the fog. Was it taken on Grizzly Peak? My home email is betty@whro.net

Jim Villers