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Initial review of MSA weber 40 DCOE carb kit


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I am trying to install a set of 40mm DCOE webers I got from MSA for my 240Z. The purpose is to get the fuel system up and running before my new L28 gets here.

I have to say the carbs are beautiful. They came set up as follows:

30mm venturi

130 main Fuel Jet

170 Air corrector

F11 Emulsion tube

55F9 idle/slow running mixture jet (I may have to double check this one, it was hard to read at night)

Naturally it came with a Cannon manifold as standard fare. Here is where I noticed my first initial quality lapse.

The cannon manifold had very noticeable casting/machining edges that protruded into the bore of each runner that I had to knock down with a file then sandpaper. I got all that smooth as butter after about an hour. When I tried to mount it to the car, it hit my old MSA headers on cylinder number 6 and would not seat onto the head. I had to pull it off and slowly remove material with the Dremel so that it would clear the header. Also, the header was 0.600" thick, and the Cannon is 0.495" thick so I had a hard time getting an equal preload on both parts, but finally after much shaving down of weld material, and washers, I got a nice load on all the bolts.

My initial impressions of the linkage kit were okay, right up until I noticed my linkage rod that all the arms that actuate each carb bolt to was slightly bent. Which meant that when it was place through all three rod ends it is VERY hard to turn.

I may have to find another one. Or at least some 0.312" bar stock and make my own.

The kit came with no return springs at all, just a note.

I am currently deciding on how I want to run my fuel lines and if I am going return line or not. I have read all the posts on that so I am still making a decision.

also, very important lesson here so listen up. If you plan to go all fancy smancy and use -AN fitting everywhere like I did prepare to get your wallet gorilla raped! Ouch, Russell is proud of that shiny stuff.

another note, do not think that a -8 AN fitting (read as 8/16" or a half inch) can fit into a half inch hole, even if it is a 1/2" NPT to -8 AN adapter. I made the mistake of getting too ambitious with my ordering and did not take the time to look at how big -8 hoses are. NPT sizes are called out referring the INNER DIAMETER (as an engineer I should not have forgotten that)

Keep everything -6 (3/8") and you will be far happier.

So now I am left to ponder two things.

What am I going to do about my bent linkage rod?

Am I going to cut my stock SU linkage rod from the firewall to mate with supplied linkage rod, or run the LOKAR cable kit

Am I going to run a return line or not.

So my impressions of the MSA redline kit are mixed. The weber product line is fantastic. But the Cannon and linkage stuff supplied was quickly thrown together.

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When you install, ensure that your linkage from the pedal does not try to turn the throttle valve plates past 90 degrees or you can twist the DCOE's shaft.

The setting for the linkage should be that the pedal hits the floor just before the throttle valve plate is fully opened.

Welcome to Weber.

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Cygnusx1 sells a nice linkage kit should you decide to change it up.

I'm curious how your progression holes up with the throttle plate. The slightest throttle opening should expose the first downstream progression hole, otherwise you'll have a stumble.

Good luck!

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I was going to video an example of just that.

What I did was turn out the lights and shined a bright flashlight into the manifold side of the carb opening. I wanted to see when I would uncover the progression holes just for the reason you mentioned. So far so good. when I applied the slighted amount of pressure to the throttle I got a sliver of light through the first progression hole. I think they may have modified the 151's. Are all butterfies on webers chamfered? This knife edge was a trick to help throttle tip in. (according to the Weber book I am currently reading :) )

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I was going to video an example of just that.

What I did was turn out the lights and shined a bright flashlight into the manifold side of the carb opening. I wanted to see when I would uncover the progression holes just for the reason you mentioned. So far so good. when I applied the slighted amount of pressure to the throttle I got a sliver of light through the first progression hole. I think they may have modified the 151's. Are all butterfies on webers chamfered? This knife edge was a trick to help throttle tip in. (according to the Weber book I am currently reading :) )

Interesting. If the progression holes are okay, then you are on your way to having a properly-running set of triples! I don't think the throttle valves were chamfered, unless someone modified them. But yes, it is a trick to get the throttle position just right for a smooth tip-in without raising idle speed or enriching the idle mixture.

Looks like you've run into the typical triple carb installation issues, e.g. mismatched manifold thickness, throttle linkage, intake hitting header flange, etc. I remember the night I decided to slap my triples on. Started the swap around 9 or 10pm and finished around 1 or 2am. I had to hear them run so I started it up with an open header in the middle of the night. Oh the joy!

LOL

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I think that you will really like the Webers once you get them dialed in. I purchased my first set decades ago and never had the patience to really understand their principal of operation and the effects of small changes to the different components of the system. In the end they are nothing more than a mechanical computer and once I had that figured out and used a more disciplined process to fine tune them, it actually turned out to be pretty straight forward process to get them to run correctly.

As a point of reference for you, the new Webers that I installed recently (purchased from Pierce Manifolds, so a differert vendor from yours) came jetted as follows:

Main 125

Choke 30mm

Emulsion tube F11

Air Corrector 160

Idle Jet 50F9

This was actually not the stock configuratiion, but one that I had requested given the starting point of my older Webers. After tuning, and using an AFM, I ended up with these settings that are much more ideal at least for the way my car is configured:

Main 115

Choke 30mm

Emulsion tube F11

Aircorrector 160

Idle Jet 55F9

Initially I did have the off idle stumble but found that the idle jet sizing had the greatest impact on resolving that. Going to a slightly larger jet eliminated 98% of the stumble that I had experienced for years. I'm sure that every car is different but this was how it worked out in my case.

As to your bent linkage, I actually went to a slightly different setup when I moved to my new Webers, but I believe that my original configuration is similar to if not exactly the same as you received from MSA. I decided to go to a different throttle rod and ended up ordering some 5/16" stainless steel stock from McMaster and just cut it to size. I believe the size of the original rod is actually 8mm, but the 5/16" turned out to work fine. I have the part number somewhere if that will help you. Also, I did have some binding issues with the setup and ended up eliminating the middle "ball joint rod end" that the throttle rod goes through. Because of the stiffness of the SS rod it worked out fine and eliminated a potential point of binding in the system.

With regard to the OEM linkage, I tried for years to get the OEM setup to work properly and keep the engine period correct in this area, but after switching to a throttle cable and experiencing the difference in drivability, I kicked myself for not doing this years ago. For me, it was the single biggest improvement to the overall drivability of the car and I have no regrets other than wishing I had done it sooner. I think the OEM linkage is actually a good design, but with all of the joints, etc, I just don't think it can compete with the smoothness of a cable.

On your return line question, I went through the same process of rethinking this again and again. In the end I went without a return and used a FPR that did not require one. I used a Summit FPR that had a range of 3 - 5 PSI and it has worked out great so far. I do have the MSA coated headers and also run a heat shield under the Webers, but at least so far I have had no issues with vapor lock or fuel starvation in general.

Finally, I think that it was Leon that mentioned the linkage kit from Cygnus. I actually have that kit installed on my car and it is far better and far nicer looking than the stock one from MSA (same one that I used to have). Dave is a great guy to deal with and even went as far as to fabricate an additional arm that I used with my cable setup. I highly endorse his product and he is a great guy to deal with.

Here's a few pictures of my system that might help.

post-19584-14150818354088_thumb.jpg

Let me know if I can help you out on anything. I think that you are in for a lot of fun times!!

Mike.

post-19584-1415081835301_thumb.jpg

post-19584-14150818353382_thumb.jpg

post-19584-14150818353731_thumb.jpg

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Mike it is scary how similar we think!

I ordered 5/16th rod stock from mcmaster car today as well as a Lokar throttle cable!

I am fabricating my own fuel rail as we speak but need to track down a drill press to finish.

I am still on the fence right now about the linkage kit. I like how it looks on your car

One question. It looks like you made some brackets for return springs on the first and second carb, why not the third?

We have very similar setuos Mike. I will be chiming in here in this thread to keep you up to date on my install.

I also have coated headers from MSA and have yet to install my heat shield.

Very close setups indeed!

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I got the air horn filters from Pierce. You can see them here:

http://www.piercemanifolds.com/category_s/172.htm

On your question about the return springs, I have tried to balance "throttle force" with drivability. With a third spring, there is too much force (in my opinion) on the gas pedal and it gets fatiguing to drive because of that. I will also way that with the old OEM linkage, the addition of a third spring resulted in a very jerky acceleration, especially off of idle. In fact this jerkiness existed even with two springs. The addition of the throttle cable has completely eliminated the jerkiness on acceleration. I have found that 2 springs gives good drivability, reasonable return to idle, and no driving fatigue.

I also wanted to make the return spring install clean, and so tried to find areas that would accomodate the installaton of a spring end. I ended up having to fabricate some aluminum brackets for the valve cover as well as the throttle arms that Cygnus made to accept the springs and still look pretty good in the engine compartment. In the end, they work pretty well and don't look too obtrusive.

BTW - Any chance that you are planning to attend the NISMO fest in San Antonio next weekend? My wife and I are planning to go and it would be grewat to finally meet you in person.

Mike.

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