Any WEBER Gurus out there? HELP!

[Mr. Potato Head]

I'm still trying to get my Webers adjusted after only one year of shooting in the dark. If anyone's running Webers out there I'd sure appreciate a little info. The engine is running very rich with minimal backfiring. There’s a noticeable hesitation between the idle and primary circuits. If I hold the throttle at 2700-3000, the transition point, the engine stumbles and burbles. Anywhere in the RPM range at full throttle, no problem, hold on, typical Webers they always run great wide open.

Here's what I'm running under the Webers:
289/347 stroker
10 to 1 compression
Dart Heads
2.02 intake 1.60 Exhaust
1.6 Rocker ratio

Cam; Isky 279/280-1
Intake duration 270
Open 27
Close 63
Exhaust duration 270
Open 63
Close 27
Intake lift 470
Exhaust lift 470
Lobe center 108
Overlap 54
Cam advance 0
Timing 20

On top:
4 weber 48 IDAs
Chokes 37mm
Idle Jet holders 55F10
Idle air jets 60
Main jets 170
Pump jets 40
Emulsion tubes F5
Air correctors 155
3 progression holes drilled

If anyone can suggest a few changes or give me there set up I’s sur appreciate it!


Thanks,
“Mr. Potato Head”
Larry Davi

[Rick 427 Cobra]

one word,,,,,,,,,,,,HOLLEY!

[cobrajeff]

I'm not the Weber "Guru", but I can give you a few suggestions.

First off, I can see why you're running WAY too rich - your mains are larger than your air correctors. Typically, the main jets will be SMALLER than the air correctors. I think you'd want to have the mains at 145 or 155, and an air corrector of 175-185.

You're not running any air cleaners are you? It's virtually impossible to get them to run right with air cleaners - they have to be jetted-down to run air cleaners - too much restriction.

You might also try an F7 emulsion tube - that seems to be the most popular one (and what's usually provide in new carbs).

Hope this helps.

regards,

cobrajeff

[MOTORHEAD]

Have you read"Weber-o-logy 101" on the Inglese web site?
I think it's agood starting point for learning what area to target for specfic problems.

[zimmy]

Cobrajeff is on the right track.

You need to increase your air correctors to 190-210. If you run out of accelleration at the upper end, then go to a smaller air corrector. The mains may be a bit too large also. I run a stroked 427 with 48 IDAs and 37mm throats and my engine seems to like the mains about 150-155 with the 210 air correctors.

You idle circuit also seems too rich. I would suggest a 110 holder with maybe a 55 jet. The idle screws should be out about 3/4 turn.

While most people use the F7 tubes, they all also seem to complain about the 2700-3000 rpm stumble issues. Try the F5 tubes. They change the point of the emulsion start and they made my system run very smoothly through this area. There has been some discussion that even F2 or F11 tubes will work very well for the street.

Be sure that they are synchronized very well also. It will account for some of the roughness or stumbles as well. Also, what by-pass valve are you running in the bottom of the fuel bowl? 50-55 bypass valves also seem to work well for most people. If you have the zero valves installed then you will run too rich on accelleration blasts. (Lots of black smoke).

If you want to talk more about this in person, send me an email and we can exchange numbers. I am very glad to help. Good Luck.

[Ford of France]

If he is running three progression holes, stumble in the mid range shouldn't be a problem. The better solution to the jet range would be 145-150 and air correctors at 200-210. The 180 main is way too rich.

The exhaust valve in the float bowl should be a 55.

One question, though, who drilled the third progression hole?

[BrianPaul]

One other thing. Make sure you are not running too much fuel pressure. My 428 was very rich at 3PSI, leaned out nicely at 2.5PSI. Just my $.02

[BB427]

Is 20 your initial timing setting or your total setting?

You will want alot of initial timing to obtain a complete fuel burn.

Webers like timing.

Brent

[Ford of France]

36 degrees at full advance is about optimal.

[Mr. Potato Head]

Thanks for the tips. (except for Rick, that solution is too easy)

The engine is definately too rich. I'll change out the mains, and start from there.

My initial timeing is 20 and total of 36, Fuel pressure is 1.5.

I contacted www.piercemanfolds.com and hopefully will get a tech out for a dyno day and get this sucker set up once and for all in a few weeks.

The car was running pretty good previously, uintil it got choked down with and inadaquate air cleaner. We chased the settings entirely too long before deternining the major problem was the air restriction. Hopefully now we'll get back on track.

Thanks,
Mr. Potato Head"
Larry Davi

[Allan A]

Larry,

Do you need help, it has to be the ball bearings.

Allan

[Randy Rosenberg]

Allan's right... Larry, have you lubricated your balls? err, I mean bearings? They do need to be lubricated occasionally?

See ya,
Randy R...

[Allan A]

Randy,

Have you tried Larry's "Sweaty Balls", they are a hit at Pot Belly.

Allan

[Mr. Potato Head]

Allen,
I'm getting a little concerned about your intrest in my anatomy. You're starting to scare me.

Mr. P....

[bbrown]

Larry,

I think the only jet that can help you is a 747.

However, I warned you I would post some info on Webers, so here goes. I talked to a few people about jetting and the synopsis is similar to the advice given here.

Main jet 145
Air corrector 210
Emulsion tube F7
Chokes 37
Bypass 55
Idle jet 55-65
Idle jet holder 120

Bert

[carmine]

maybe you weber gurus might have a suggestion on a good starting point for my 48 ida weber endevor, a-top a 351 windsor stroker 427 cubes.
current
choke 42
main 175
e-tube F7
air corr 155
idle 60
idle air 60
pump 45
pump exaust 80
3 progression holes drilled
compression ratio 10.5-1
cam specs- hyd roller,1.6 rockers
duration advertised 304 in 304 ex
duration @ 50 244 in 244 ex
lift 576 in 576 ex
lobe sep angle 110 deg.

any sugestions to these current weber settings would be greatly appreciated.
Regards Carmine

[Mr. Potato Head]

Thanks Bert,

Were those settings on a 747?

'Mr. Potaot Head"
aka Larry Davi

[zimmy]

Carmine:

You are running very rich as well. You should also see the above posts. For the street, the general starting point would be as follows:

37 mm throats

210 air correctors
145-155 mains
F7 or F5 tubes
55 bypass valve
120 idle jet holders
55-65 idles

I run this setup on my 427 stroked to 454. Should do you well as well. Good Luck. Let us know how you make out.

[carmine]

thanks zimmy.
unfortunatly can,t try out your recomendations yet because engine being built as we speek. wanted other opinions on settings that i had posted because those were the settings that pierce manifolds set in my perchased weber set-up from them. thanks again on your imput Zimmy, will keep you posted on the finall results.


PS: does anyone have any comments on my cam shaft specs and if they feel it will or will not work well with the webers a-top my 351 stroked 427 cubes engine