Interesting Weber jetting - Page 3

Eljaro · #1 (**permalink**) 05-04-2007, 01:26 AM

Hello Chuck,

I made the F14 emulsion tube myself, because I could not find any.
I used a F7 tube, drilled the inside diameter to 3.5mm (it is 3.0 now) and made myself a sleeve with an interior diameter of 7.5mm and an exterior diameter of 8.2mm, length 12 to 15mm.
I used brass. You have to drill on a lathe first to 7mm, then to 7.5 to make the hole as exact as possible.
Then you turn the exterior diameter to 8.2.
Do not remove the burr for now from the edges as this will help to slip the sleeve tightly over the F7 tube.
Click image for larger version Name: F14.jpg Views: 40 Size: 18.5 KB ID: 12161
I include a picture of how this looks like. http://www.clubcobra.com/forums/atta...1&d=1166659604
You have to drill four more holes in the top row (it has only four now) to make a total of 8.
These are the tubes I have in my car right now and they work very well.
Good luck, and let me know how they work out for you.

I am glad to hear that you noticed the improvement with the 40mm chokes. No try to get the transition sorted out and you will experience the real weber feeling.
42 mm chokes may work well too. Just a matter of trying it out.
Stefan

ENTDOC · #2 (**permalink**) 05-06-2007, 05:55 PM

Stefan, do you think a F16 tube is similiar enough to a F14 to yield good results? They are readily available. If not, what other tube would you suggest? thanks; chuck

BERNIE · #3 (**permalink**) 05-22-2007, 11:28 PM

Quote:

Originally Posted by Eljaro

Hello Chuck,

I made the F14 emulsion tube myself, because I could not find any.
I used a F7 tube, drilled the inside diameter to 3.5mm (it is 3.0 now) and made myself a sleeve with an interior diameter of 7.5mm and an exterior diameter of 8.2mm, length 12 to 15mm.
I used brass. You have to drill on a lathe first to 7mm, then to 7.5 to make the hole as exact as possible.
Then you turn the exterior diameter to 8.2.
Do not remove the burr for now from the edges as this will help to slip the sleeve tightly over the F7 tube.
Click image for larger version Name: F14.jpg Views: 40 Size: 18.5 KB ID: 12161
I include a picture of how this looks like. http://www.clubcobra.com/forums/atta...1&d=1166659604
You have to drill four more holes in the top row (it has only four now) to make a total of 8.
These are the tubes I have in my car right now and they work very well.
Good luck, and let me know how they work out for you.

I am glad to hear that you noticed the improvement with the 40mm chokes. No try to get the transition sorted out and you will experience the real weber feeling.
42 mm chokes may work well too. Just a matter of trying it out.
Stefan

Eljaro,
Find F14 from pierce manifolds (expensive,but!!!)
Bernie

Cal Metal · #4 (**permalink**) 11-17-2007, 01:56 PM

Eljaro:

I might have missed this in a previous response, but what was your experience if you employed the F14 without any additional drilling. What type of response did you have, particularly in the transition stage?

Thanks

CM

Gun Doc · #5 (**permalink**) 11-18-2007, 10:02 AM

I ordered my parts from Top-End Performance (http://www.racetep.com/)…Good prices quick delivery and great customer service.

Gun Doc

ENTDOC · #6 (**permalink**) 11-18-2007, 10:52 AM

you may be right on the filters Ray, perhaps 40's will overcome them.

JCoop · #7 (**permalink**) 12-01-2007, 04:16 PM

Quote:

Originally Posted by ENTDOC

you may be right on the filters Ray, perhaps 40's will overcome them.

And it's confirmed! I just installed a set of 40mm chokes and the motor feels like a totally new machine. It was a fairly easy swap except now I know to be very careful when pulling the squirters out not to lose the O rings

The set I got from Vee Dub Parts were beautifully machined pieces, a far cry from the original 37mm cast ones originally in there. They slipped right in, nice 'n shiny.
I just drove a mile home from the shop; not even far enough to warm up the oil but without touching anything else, the idle is smoother, no spitting, sneezing or coughing coming off idle, and a quick blip of the throttle and she just jumped without any hesitation or transitional hiccups. Yey!

I gotta give her a workout tomorrow!

ENTDOC · #8 (**permalink**) 12-01-2007, 04:28 PM

let me know how it all works out as I am about to finish the CAV upgrade with Ians shifter, IDA's and sound deadening.

Eljaro · #9 (**permalink**) 12-02-2007, 10:30 AM

Quote:

And it's confirmed! I just installed a set of 40mm chokes and the motor feels like a totally new machine. It was a fairly easy swap except now I know to be very careful when pulling the squirters out not to lose the O rings The set I got from Vee Dub Parts were beautifully machined pieces, a far cry from the original 37mm cast ones originally in there. They slipped right in, nice 'n shiny.
I just drove a mile home from the shop; not even far enough to warm up the oil but without touching anything else, the idle is smoother, no spitting, sneezing or coughing coming off idle, and a quick blip of the throttle and she just jumped without any hesitation or transitional hiccups. Yey! I gotta give her a workout tomorrow!

Well, glad to hear that the 40mm Venturis work well on a 302 also.
Dont know how come the word spread that the 37mm were the chokes to use for everyday driving.
Maybe for the layman in anything mechanic it is best to leave the webers as they come, but for anyone wanting to tinker around it is fun and definitely brings driving improvement. Doesn't it ?
I bet once you try larger chokes you get the real Weber feeling.

Rick Parker · #10 (**permalink**) 12-02-2007, 06:55 PM

dlampe

You have PM

jimf · #11 (**permalink**) 09-30-2008, 11:37 AM

I have watched this thread with great interest as a while ago I bought a weber 48 ida conversion set up for my 393 W stroker. I plan to install it soon. Before I do install it, I am changing the 37 mm chokes to 40mm right away as this engine is built to breath. One thing I am curious about is when you change to larger chokes would you not also have to change the auxiliary venturis to a larger size. I have seen no mention of doing anything with the axiliary's. Although there is not a great selection of auxiliary's there is one size larger (5.0) than what is in there right now(4.5), just wondering if anyone has changed any of these and what the results where.

Hans-Olof Blom · #12 (**permalink**) 10-01-2008, 06:43 AM

Eljaro,

This is very interesting. I have a 482 engine that I plan to put a Weber 48 IDA set-up on.

What cam are you using?

What chokes are you using?

rokndad · #13 (**permalink**) 10-01-2008, 06:45 PM

Sr. Eljaro,

I have the same question Hans made about cam, duration, lift, Lobe Separation. I want to consider Webers for my car and am watching your very expert "dialing-in" with great interest. Thanks for all your hard work.

Gaz64 · #14 (**permalink**) 10-02-2008, 01:40 PM

Eljaro,

Love your thread, I have learnt a lot.

Just one question with your pump bleed, even a zero bleed should vent back to the bowl since the inlet ball is not seated at rest, it seats when the pump is activated, I'm thinking the pump outlet check valves need to be heavier?

Your thoughts?

Eljaro · #15 (**permalink**) 10-07-2008, 08:59 PM

Quote:

Originally Posted by Hans-Olof Blom

Eljaro,

This is very interesting. I have a 482 engine that I plan to put a Weber 48 IDA set-up on.

What cam are you using?

What chokes are you using?

my cam has the following specs:

duration- intake 242, exhaust 248
LS- 110 degrees
lift- .645 intake and .635 exhaust..

I have run the webers successfully with the 40mm chokes, and am now in the process of tuning the 42mm ones. Takes a totally different emulsion tube (the F14 is no good any more!). If the weather this next weekend allows I will be fine tuning and will post the results.

Rick Parker · #16 (**permalink**) 10-02-2008, 03:07 PM

I recall reading that on the FE with an angle milled manifold the the nozzels had a tendency to drip because that with the carbs at an angle the check balls were not fully on their seat??? Not sure if that is fact but I'm just repeating what I read in another thread or website.

Gaz64 · #17 (**permalink**) 10-03-2008, 01:25 AM

Yes this could be the case with carbs that are mounted beyond the maximum angle as designed by Weber.

I haven't seen a spec for deviation from the vertical plane for IDFs or IDAs, but the maximum recommended above the horizontal plane for DCOEs (sidedraughts) is 7 degrees as specified by Weber.

I have DCOEs going on one of my other cars, I haven't measured the angle yet, but I know it will be close (touch and go).

I think that how the float can control the average float level has a bearing on this.
With the downdrafts, if they are tilted towards the pump jet side of the carb, does this bring on this issue?

Eljaro · #18 (**permalink**) 10-05-2008, 11:20 AM

I do not know what how the check valve in the bleed jet exactly works, but you can blow through it one way only if it is a 0.00 one. On rest it apparently is closed and the gasoline in the pump circuit boils over, creates pressure and escapes through the pump jet into the throats.
With the 0.50 bleed this did not happen, so it looks like the pressure in the pump circuit escapes through the bleed hole and you do not get the nasty spill. Unfortunately the .50 spill is too much and creates a slight bog, so I am waiting for a set of 0.35 to arrive
At times I thought this had all to do with the float height and heat to the carbs through the gasket, but I have learned that it has nothing to do with that. I have the brass float at 4.2mm from the lower carb body surface, and it is ok so, since it compensates for the inclination of the carbs. I double checked on that and it is the best adjustment so far.
I am even thinking of removing the 10mm heat isolators from the carbs, which give me headaches because they raise the carbs and the air horns are touching the hood and pushing the two front right horns off its seat in the carb all the time.

I could not find .85 air corrector jets, so I took 2.20 air correctors . filled the holes with tin solder and drilled on the lathe a 0.75mm hole, which is the drill bit I could find around here. Works perfectly and gets away with top end leanness. Tried them out today with great success.

Gaz64 · #19 (**permalink**) 10-05-2008, 01:25 PM

Yes, unlike an old Holley with it's steel inlet valve, the Webers inlet valve is very light and when submersed in fuel would be floating shut.
I always thought they were a "hanging ball" (non seated) like an early Holley.
It's a shame Weber doesn't make one smaller than .35, they must have thought there's not much difference between a .35 and 0.00.

A .35 is near enough to a number 80 drill bit, but you can get metric drills.
I have a set down to .3mm, so you could make you own .30mm bleeds.

Eljaro · #20 (**permalink**) 10-06-2008, 12:13 AM

0.35 mm bleed is half the surface as the 0.50. It will probably be better than the 0.00, because when I had the 0.00 on I did get a black cloud coming out the exhaust on acceleration. The bog with the 0.5 is minimal now, so 0.35 will probably be best. I will find out when I get the jets.
Drilling 0.35 mm on a curved surface is going to be a nightmare. Those drills break just by looking at them and they are not cheap. Maybe still best and cheaper to get a set of bleed jets. I got them from http://www.dellorto.com/