weber settings and backfire

[Gaz64]

Technically if the mixture screws are at a base line setting, the airflow per barrel is adjusted first, while keeping the engine at say 1000, adjusting linkage as necessary to have all barrels flowing the same. The mixture screws alter engine smoothness, and each cylinder can "go away" with too much one way on the screw, and although there is air flowing though the mixture discharge port, the adjustable volume doesn't make significant difference to a synchrometer reading.

Get the carbs balanced correctly at idle, and check airflow balance at part throttle of 2000 or so rpm. Once balanced at idle, the carbs should be checked for mechanical balance at wide open throttle with the ENGINE NOT RUNNING.

Good baseline tune, good linkage, easy to adjust, can you give EFI smoothness.
I built a 2.1 Pinto a few years back with a pair of 44 IDFs for a friend, and even with a 250 @.050 cam, it had virtually no cam lope. I should have went up one grind.

Gary

[paul cass]

Hey Gary
Took the FIA out for a run this afternoon and boy what a difference. Ran almost exactly like when I had the carb. Occasionally I noticed that after stop and go I would have what seemed to be a cylinder go away. Blip the throttle and it usually cleared up. I'm running an 80's era Ford AOD that I manually shift. Stall convertor is 2900. A little different from a manual transmission. Had good idle, good performance on acceleration with no stumble. This under normal driving conditions. Once I got away from traffic I stomped the gas pedal and the FIA went like a rocket! When I got back to my shop I checked to see if there was any flooding after I shut down the engine. One carb had some slight flooding. I think that this is the one that had a different needle than the other 3. I won't have time to tinker again until Friday. But needless to say I was a very happy camper this afternoon. On the other post I mentioned that all of the floats were set at the wrong height. 4, 4, 3, and 5. Reset at 10 mm. Seems if you spend thousands of dollars on a set up the least they could is to set the floats correctly. Oh well. I'll further update later in the week.

[Gaz64]

Good to hear you are making progress Paul.

I would replace the needle and seats with the same type, then reset the float levels to 10mm.

Can you list your carb tune settings, choke, main jet, emulsion tube, air corrector, idle jet, pump jet, pump exhaust?

Or are they as factory set for a 44 IDF?

Gary

[paul cass]

Hi Gary
I don't have any specs on the Weber's. I've asked for that info, both from Top End and Red Line. Nothing from Top End and the guy with Red Line told me to take apart the weber and see what parts were in it. I plan to try again to get some info. See what happens.

[Gaz64]

Hi Paul,

Sounds like your 44s are still are factory settings.

Redline probably doesn't give a more appropriate setting for your engine capacity.

I know my 44s weren't big enough for my last setup, I wish I went to 48s.

Gary

[paul cass]

A quick update. After sending an email complaint to Top End it was forwarded to Red Line. Bud from Top End contacted me and was very helpful. For whatever reason it seems that this "brand new" set up had a few issues. All the floats were not set. 5 mm closed, 30 drop down. All the mixture screws had pitting. And one of the idle jets was in two pieces. I used 2000 paper to sand out the pits and reinstalled, set the floats at 14.5 and 22.5 and reinstalled. Started the engine and went through the process of readjusting all of the mixture screws. This time all had some effect on the engine's idle. Took it out for a cruise over the weekend and YES, finally it ran pretty good. The best yet. Go up and down thru the gears with no problem. Occasionally I do get a couple of pops when I slow down quickly form the passenger side pipe. Sent a follow up email to both TE and RL but have yet to hear from both.

[Gaz64]

Paul, can you show some pics of what you found?

Geez, at 5mm, lucky it wasn't flooding more often.

14.5 seems a bit low,(a big drop from 5mm), I like 10-11mm.

The drop is not as critical as level, anywhere from 20mm up is ok.

Gary

[CHANMADD]

When going to adjust multiple carbs, I have found almost every time that the blades are not in proper sinc. They have to be the first adjustment...the crank the fast idle up a bit and then adjust the idle screws . If you don't have a vacuum gauge synchronizor, then get a length of ...like fuel hose and hold one end in your ear and the other move from venturing to venturing ,until they all suck the same...

[paul cass]

[paul cass]

may be hard to see, but some had more spots than others. All were black dots.

[paul cass]

[Gaz64]

Yes, the black dots polish off, something from production, possibly corrosion within the idle port after assembly.

The idle jet in an IDF is a separate piece to the idle jet holder like most Weber carbs.

Gary

[paul cass]

The one idle jet came apart but the other 7 were intact. All but one of the screws did polish out. Along with the floats and a couple of other things it is still disappointing to get a "new" product with so many problems.

[Gaz64]

That's how the idle jet works, they pull apart with your fingers if you wish to change the idle jet.

[paul cass]

Hi Gary
I understand that the jet is supposed to come apart, but one was apart in the carb. It would not stay together. I've had a really busy schedule here the last couple of weeks and will not have a chance to do any more follow up for a couple of weeks. And, even though I sent an email to both Top End and Red Line almost three weeks ago I have yet to hear back from them. But the last time I took it for a cruise it ran really good. Tennis and son's wedding will occupy my time until the end of the month. Hope everyone has a wonderful Memorial Day weekend.
Paul

[YerDugliness]

I just ran across this thread, will post a link from the GT40s forum, where Webers seem to be the first choice whenever possible. First is a link to a YouTube video regarding tuning Weber carbs:

Weber Tuning Tutorial - On YouTube - GT40s.com

In addition, I ran across this CC article explaining the overall operation of Webers in general, posted by Tom Kirkham:

http://www.lainefamily.com/images/WeberTuningManual.pdf

They're tricky to sync, is what I've heard.

Cheers and good luck with your project!

Doug

[paul cass]

Hey guys. Back from my travels. Son had a beautiful wedding and I had a great tournament. Played the Westwood Senior Open a Category II National event played on clay in Austin Texas. I won the 70 and over singles, upsetting the #4, #2, and #1 seeds along the way. As for the FIA it seems to be running just fine. Switched to Shell fuel and noticed a big difference when mixed with my 110 leaded. As to Top End and Red Line, not a word. Sent both a couple of emails about my displeasure but no response. Guess we live in a different time than when I grew up and customer service was a given. Paul-the little guy on the left.

[Gaz64]

Geez, you're looking good for "70 and over" Paul.

Gary

[Tom Kirkham]

This is the best tool I have found to set float levels on 48 IDA. I was amazed at how far off my factory set floats levels were.

JayCee Weber IDA Height Gauge

[Gaz64]

Yes, if Webers only came with pyrex sight glasses like a late Holley, Demon etc .

OER Weber DCOEs have external adjustable float level like a Holley.

If only IDAs and IDFs had that feature.