Weber guys, I need a measurement.

dlampe · #1 (**permalink**) 03-29-2011, 08:29 PM

Alright, here is what I have discovered about my set up. I have 2 Italian carbs and 2 not Italian. The main jets screw further down in the carb bodies in the Italian carbs buy 1.5 mm. If the floats are set to factory specs, (5.5mm above the surface and the tang 24.2 down in the bowl) and if you lay a flat edge across the two main jets and measure down to the top of the float what is that number? There should be a hole in the top plate right over the float if you don't want to disassemble the carb.

Lets say the number is 13.5 mm on 2 of mine and 15mm on the other two. My floats are set to factory specs. Would I need to raise or lower the float setting on 2 carbs so the float(fuel level in the bowl) is in the same location relative to the e tubes on all four carbs? I realize that measurement is not going to be real easy to get but i really need to sort this out.

Thanks in advance to the poor soul that gives me this number!

Tom Howland · #2 (**permalink**) 03-29-2011, 10:58 PM

My carbs are made in Spain. I measured from the top of the main jets through the hole to some obstruction. Got 22 mm. I'll be doing some major tuning tomorrow so I'll take the top off and get some more measurements.

Gaz64 · #3 (**permalink**) 03-30-2011, 02:00 AM

Dean,

Sorry I have reread your post and understand your dilemma.

It then becomes the relationship of fuel level, e-tube hole height and auxilary nozzle height.

Pity the Spanish can't copy the Italians correctly.

dlampe · #4 (**permalink**) 03-30-2011, 06:16 AM

I think I could shorten 4 of the e tubes by 1.5 mm so the relationship between the fuel level and the tube is the same but that will through something else out of wack. I guess I am starting to wonder if this "set" of Weber's can play nicely together?

Clois Harlan · #5 (**permalink**) 03-30-2011, 06:51 AM

NOPE!!!! It is time to put the webbers where they belong....on the shelf or Ebay.

Get a nice 850 Holley DP and an old fashioned aluminium medium riser dual plane intake and have some fun.

K.I.S.S. - good words to live by.

Tom Howland · #6 (**permalink**) 03-30-2011, 11:34 AM

Took 2 tops off and got 12.5 mm on both. The 22 mm was pushing the floats to the bottom. Don't modify the e-tube. That would change the air flow. I would change the float level. That can be changed back easy.

dlampe · #7 (**permalink**) 03-30-2011, 12:07 PM

So do we agree that the float level/ etube relationship must be consistant on all carbs even if that means that 2 carbs have more fuel in the bowls?

Jac Mac · #8 (**permalink**) 03-30-2011, 01:10 PM

Quote:

Originally Posted by Clois Harlan

NOPE!!!! It is time to put the webbers where they belong....on the shelf or Ebay.

Get a nice 850 Holley DP and an old fashioned aluminium medium riser dual plane intake and have some fun.

K.I.S.S. - good words to live by.

That is an automotive principal that I doubt Dean will ever get to grips with pity, he would have sooo much more fun if he could!!

Tom Howland · #9 (**permalink**) 03-30-2011, 01:40 PM

I think the issue is the volume or head pressure at the main jet. Of course the float height will change the volume. But you don't know if the casting is the same between Spanish and Italian. Making the height the same might also even out the volume. Try changing the float height.

dlampe · #10 (**permalink**) 03-30-2011, 06:12 PM

Thanks for the support Jac!

I just took it for a drive after I changed the floats. I really couldn't tell a difference. All of this is probably not a big deal. Switched to the f16's from the f7's and it was worse. I changed exhaust jet from a 55 to a 40 and it seemed to run a little better. I am going with a 00 exhaust and see how it runs.

I am currently @

Idle jet 60 w/ 120 holder
main jet 160 with a 120 air corrector
40 mm chokes.

Rick Parker · #11 (**permalink**) 03-30-2011, 10:36 PM

Clois: Go wash your mouth out with SOAP!

Clois Harlan · #12 (**permalink**) 03-31-2011, 07:43 AM

I'm sorry Dean and Rick I just couldn't help myself!

I remember the old days when Dean and I would go to a track and actually race or spend many many miles and laps on a track. The last few years as I was moving on to the track hot grid all I could see was Deans butt in the air while he was adjusting something on one of his cars.

Sorry!

barry950 · #13 (**permalink**) 03-31-2011, 11:34 AM

Dean,
I think the issue here is the relationship between the top of the casting and the transfer passage to the boosters, not the depth of the main jets. Try F11 emulsion tubes, it worked for us.

dlampe · #14 (**permalink**) 03-31-2011, 03:00 PM

So if that is the case, then the float height needs to be set relative to the main jet, not the carb casting? I guess I would need to confirm the height of the transfer passages and their relation to the main jet as well as the casting.

Gaz64 · #15 (**permalink**) 04-01-2011, 02:25 AM

Dean,

I would think the booster nozzle height would be the same between the S (Spanish) and I (Italian) carbs.

With the whole e-tube assembly sitting lower, the first row of holes becomes exposed at different airflows between S and I.

If you lower the float level to make the first row of holes all even in respect to the fuel level, then the S carbs have to lift the emulsion higher to get to the nozzle.

Some would call it being picky, as you may be chasing something you'll never be able to tune out with "normal" practices.

I personally feel you should have 4 carbs from the same country, be it Italian for authenticity or Spanish for cost.

Rick Parker · #16 (**permalink**) 04-02-2011, 02:23 AM

WOW I've been chcking on this for a few days and my head hurts. Remember Physics 101........"Liquid seeks its own level" I think the dimension you want to fine tune would be the static level of the fuel in the main well (jet assembly removed) and the bottom of the well where the main jet seals in its tapered counter bore. This will in turn mean the standing level of the fuel is uniform and the various holes on the emulsion tubes are uniformly exposed and ready for action. Any fluctuation in this dimension between carbs regardless of origion will cause irregularities in A/F ratios throughout the RPM range as well as poor transition and stumbling. If the dimension of the transfer tube to the jet seat is different between the Italian castings and those from Spain I do not think it can be "Tuned Out" and you will constantly have transition timing differences. JMO

dlampe · #17 (**permalink**) 04-02-2011, 07:12 AM

That is exactly right! The distance from the seat to the passage way is about 1 mm off. It would be almost impossible to machine the seat deeper so I was looking for the next best thing. I was trying to keep the holes in the e-tubes consistent and I couldn't think of any way to do that other than shortening the e-tube by 1 mm.

Having put all of you through this diatribe, I must tell you that these have ran fine on other cars and with fuel sloshing around due to bumps in the road, it probably doesn't make any difference. There might actually be some margin of error allowed here.

Xavier · #18 (**permalink**) 04-02-2011, 08:16 AM

Dean,

The Webers distributed by Redline from Spain had major modifications to them to make them easier to tune and make them more streetable. I would call Redline and review the differences for tuning. The person who tuned my carbs were unaware of the changes and it lead into a whole learning process, as he was used to working on the Italian original models. Nothing that could not be easily adjusted for, but it was different and what he had to do was unique from the Italian models. When talking to Redline, they will tell you if they tuner is used to the Italian models without referring to the handbook or calling, the tuner will goof it up (as mine was, and wad a little embarrassed he did not know about the difference).

Point is, there must be a good difference. The guys at Redline are very knowledgeable.

Rick Parker · #19 (**permalink**) 04-02-2011, 10:22 AM

I think you are describing the 3rd hole in the idle progression system.

Dean: The vertical dimension difference will require more depression (vacuum) to bring the main circuit on line. You may be able to tune around it with smaller so correctors on the carbs in question.

Jac Mac · #20 (**permalink**) 04-02-2011, 01:22 PM

Rather than shorten the E-Tube, I would simply fit a 1mm thick washer between the main jet & E-Tube of those that are sitting lower, therefore bringing all the E-tubes UP to the same height. Should be able to get suitable washers from a model car/plane shop or electrical repair firm that actually does repair work instead of sending it away to a major service 'center**** Do they still have shops like that in USA??

Down side to anything you do is you will always have to remember which bits come from which carb.