FE guys with Webers ?????

[BB427]

48IDAs on FE (in my gallery)
2.5 lbs fuel pressure
float level is ok

Car is very rich at idle and the idle adjustment screws are only out 1/4 to 1/2 turn. The car blows black smoke and runs very ruch up to 3000 rpm. WOT is great though.

The set up has a 60 idle jet. Is it too much???

What are you guys running.

Thanks for any input you have .

Brent

[427Aggie]

Wow...Brent..ok need to check a couple of things...whats the total setup...Idles, Holders, Mains, emmulsions, air correctors, chokes, bypass valves....How did you check the float level? How do you know its ok?

Matt

[zimmy]

I agree with Aggie. What idle holders are you running? Also - it does sound like your floats are too high. I am having similar issues with mine and I also have throat dripping after shut down. I am going to be checking the float heights next. I am pretty sure that they are too high causing everything up to the main circuit to run rich.

[BB427]

It runs great after 3000 rpm so I think the main, air correct, and emulsion tubes are OK. It has a 60 idle jet and a 60 holder.
To check the floats I was told to remove the emulsion tube assy. and look down into the opening with a flashlight and locate the feed hole and the fuel level should be about 2 mil. below that. It was and I could shake the car and see fuel slosh into the tube.

Brent

[zimmy]

Brent:

Your idle jet holder is way too small. It should be about 120. That is what is making your idle & progression circuit so rich. Try the 120's.

[BB427]

Zimmy,
I know the 120s are the standard holder and I have questioned this with my carb builder. He (Mike @ pierce)told me the smaller holder is the reason I have no hesitation or pop at the transition between the two circuits around 2500-3000 rpm. (A trick they have learned over the years)
I have thought of that and I may try it if I can't get a handle on it.

Thanks
Brent

[Cracker]

Doug @ Pierce told me to go down to 80's from the 120 holders because I'm getting the little pop/spit at about 2,800-4,000. If I don't dial way to much advance in it spits. They believe the circuit is running lean which in their opinion is causing the problem. Hence the object is to rich the idle transition period by lowering the holder. I think my next try would be 100 instead of droping way down to 60 or even 80. Let us know.

[BB427]

Tony,

Thanks for the reply. That is the exact wording Mike used on the phone today and I do understand his thought process. I just think the idle is too fat and I could compensate for the transition period with less jet and holder.As you said.

Thanks
Brent

ps. cal where are you??? Chime in at any time.

[427Aggie]

Ok lets get by the pop spit....remember pierce is sizing things off numbers in a calc not how they run..I had a disagreement with Mike when setting up a friends BB Setup. I originally from pierce had 40MM and they wanted to put in 42's..forget what they tell you they will also try to get you to drill another progression hole..forget it

Here is what you check and set....and trust me and I think Cal can vouch for it I have done ALOT of tinkering with these things and I finally put it on the dyno the other day to see what it was running and changed the chokes to see what happened...YOU NEED

37MM Chokes, 120 IDLE HOLDERS, 65 IDLES, 200-210 Air Correctors, F7's, 165 Mains (this is just a starting point some tweaking on the mains idles and airs will be needed) and 55 BYPASSES!!!! Have you checked the bypasses? Pierce put 0's in mine since it was a fresh engine and let me tell you its great until you get it under load and then all hell broke loose.

For setting the floats...you can get an idea from looking down in the bowl but to set them correctly and the same you need to disassemble the carb and use the measuring end of a mic to see how far the tongue that hits the needles is from the stem...this should be the same for all carbs....Also if you have the original needles email CALMETAL and get a set of the D&G needles and seats from him...much better and will stop any possibility of leaking through the needles.

Pop spit through the carbs can be lean...but it can also be that you have too much overlap in the cam and your intake and exhaust is open at the same time...remember the carb has no runner to share with other cylinders to suck it back down through...

I had mine on the dyno and with the above setup I was running a lean on the top end over 4000 but it corrected by 6000 and I was running way rich on the idles at 11.5 while cruising...thats why for mine I am going to drop the air corrector to 200's and the idles jets to 60's..and I should be perfect.

Even though its not really rich when I punch it it pulls hard and you won't know you are too lean until you find a melted piston....

Also this is the recommended starting setup from Enzo and CalMetal.

Oh yea are you running any air cleaners on the carbs? If you are then you will never get them set right...those little strainers will cause you to run pig rich no matter what.

Matt

[Cal Metal]

I'm chiming in. That 60 holder is way too small. Remember that the holder is simply an idle air corrector. If you restrict the size, it minimizes the braking action on the fuel; therefore, you are going to run much richer with a smaller holder. I would try a 120. I have seen some some FE motors requiring 50 or 55mm idle jets., as well.

Aggie has worked hours on getting his system in shape. If you have some leakage in the throat, either the float level is too high (Aggie can give you my system on how to measure them) or you are leaking after the engine is shut off. The Weber needle/seats are prone to leak into the main bowl (often times the last carb in the circuit suffers for it). You can pick up some D & G Grosse Jets that will cure the problem (I have just a few sets left) and/or run a return line back to the tank.

Please let me know how the smaller holders work. This is always trial and error and I would be interested in the results.

The third progression hole does work very well but you need to know someone who can do it correctly. It is really a last resort if you have trouble with the transition that can't be cured. The 50 or 55 bypass should take care of that, however.

Aggie: A question for you. Tell me exactly what happened with the bypass valve that had zero return in the valve.

Good luck guys.

[427Aggie]

Hey Cal...god I love the information you have on tap in that mind of yours referencing webers...when can we get you to come to Austin or Tulsa so we can all hang out?

When I first started I had the bypass with 0 in...the car would idle great run, rev and just sound great in the driveway but as soon as I put load on the car it bounced jumped and flooded the crap out of the car...I think there were alot of things that caused it but with the bypasses changed out to 55's I could drive it. It must have caused such a richness problem that it couldn't run..now keep in mind thats before I got the floats set and so I was rich as pig to begin with but its a contributor...I may change them back to 0's and put it on the dyno to see what it does if you want to know how it changes a setup that is correctly set...similar to what I did with the 40MM chokes.

Matt

[427Aggie]

Brent,

What ever happened with your carbs? Did you get things worked out? I was curious.

Matt

[BB427]

Matt,

I questioned Mike @ Pierce about the small jet holder and he informed me that this is the way they overcome the 2500 to 2700 rpm "pop" or "lag" associated with Webers. We had a great discussion about the fuel today compared to the heavy fuel from 30 to 40 years ago. Todays fuel is so much lighter that it takes 1.2 times as much to achieve the same result. Todays fuel injection with 60-160lbs of fuel pressure works well with this fuel but a 40 year old carburator won't without some changes.
To make a long story short, I left the 60 jet holder and dropped to a 50 idle jet . My idle screws are all between 1-1/4 and 1-1/2 turns and it runs great. It starts easily cold, shuts off quickly, and starts as easily hot as it does cold. The road manners are great and Mike was right ,I have no issues with the transition between the idle circuit and the main circuit. The factory 120 holder changes the entire fuel curve and it acts rough at 2700 rpm and does not really clear up until after 3000 rpm.

Webers ROCK!!!!!

Thanks for asking!!

Brent

[427Aggie]

I was curious about what happened..I would suggest that you take it to a dyno that can run your A/F for you...it may suprise you....I thought I was running way rich and it turned out it actually was lean...but I still got black smoke which is a sign of richness.

I am curious what you are running on your bypass valve? If that was a 0 then yes taking the idle holders down should make that kind of difference...Also are you running any filters on the carbs? This could also be a reason for the richness......I agree that Mike and the others are a wealth of knowledge and are great guys to speak with.

Matt

[BB427]

No filters. I just bought a set of larger aluminum velocity stacks and I am polishing them now. I am going to plug my hood scoop and leave the carbs. open.

Brent

[BB427]

Matt,

I have finished them and they run AWESOME!!!!

Thanks for the help everyone

[Cal Metal]

BB427:

Interesting results. It does show how variable these systems can be depending on how the engine is built. The 60 holder is interesting.

[BB427]

Cal,

I am learning as I go. It is unlike the Holley world were everyone knows something about them. In the Weber world only 1 out of 10,000 people have ever messed with them.

Thats why I like this forum, Instant Help is always available

Brent

[Lubrecon]

Aggie or Cal:

I am putting 48 IDA's on a 408. I have read all of the info both of you have posted, and would like a starting point. The LS on the cam is 112 degrees, and I will get you the cam specs tomorrow, they are at the office. I would like to know if Aggie's set up on the FE will work for my 408, i.e., 37 mm chokes, 160 mains, 200 AC, 60 idles, 120 holders, 55 by pass, and F7 tubes, since the 427 is close to the 408 of mine.

I have a friend telling me I need 40 or 42 chokes on this much displacement, but Dan at Inglese says 37's are fine. My friend has 42's on a 302 and loves them. However, he races the GT 350 and the high RPM's could mean the difference.

Your comments and suggections are requested and respected.

I live in Houston, and my office # is 281-890-6400.

thanks,

Jerry Shelby

[427Aggie]

Jerry,

I think itsonlymoney will attest to this but if you are planning on driving on the street PUT THE 37"S on it. You are not running at 6000 RPM all the time and the bigger chokes will make the progression terrible. The setup you listed is a good starting point. You should always plan on having to spend a little on jets to just tune it in from there. The main thing on the cam is to not have alot of overlap. Itsonlymoney's cam in his shelby is a high lift and lopey cam but Keith specd it with very very little overlap and we have seen no pop back through the carbs unlike what I get...mine is the on the bleeding edge for webers.

Matt