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Dead horses, beaten here - 1bbl tuning and alternatives
https://www.slantsix.org/forum/viewtopic.php?t=10509		 Page 1 of 1
Author:  72swing [ Mon Sep 27, 2004 12:49 pm ]
Post subject:  Dead horses, beaten here - 1bbl tuning and alternatives
WTF,

I've been tuning this 1920 forever!!! I get it tuned where the idle is crap and it won't idle cold, but it runs GREAT hot. Or I can get it to idle like a dream when cold and warming, but then it dies when you put it in gear warm :shock: . ACK!!!(Sorry, I had to vent a bit)

I've put a rebuild kit into it, but it won't stay tuned. I've checked for vacuum leaks and I am fairly confident that there aren't any manifold or hose vacuum leaks. Somebody suggested going to a carter BBS on this application, is that any better? Suggestions?

Any information is greatly appreciated.
Author:  Reed [ Mon Sep 27, 2004 12:58 pm ]
Post subject: 
Have you tried increasing your main jet size to a #61 or #63? If it were me I would tune it to where it runs good hot then mess with your choke adjustments to get cold idle back to normal.

Alternatives are limitless, depending on how much money and time you want to spend on a new carb and tuning. If it were me I would get the 1920 running well and work from there.

Also, make sure your distributor vacuum advance is connected to the right port on the carb and that any EGR and OSAC valves are rendered inoperable.
Author:  72swing [ Mon Sep 27, 2004 1:06 pm ]
Post subject: 
Quote:
If it were me I would tune it to where it runs good hot then mess with your choke adjustments to get cold idle back to normal.
It's currently set up that way. The choke / idle choke settings are bewitching me though. With the idle screws set where they should be it runs up over 2k when started cold (but because of that engine speed can be put in gear and driven though rough on the tranny), and when it gets warm then the warm engine idle speed is just right. The worst problem is between warm and cold, the engine smells like it's running really rich and will die instantly if you put it in gear. Once it's Nice and hot (normal warm operating temp) then it idles fine and shifting into gear causes no problems. The vacuum advance seems to be correctly connected (According to the diagram I have).

Has anyone actually bought one of the Holly/carter $80 dollar webber knock-offs from stovebolt? and what does removing the intake carb studs intale? Are they just screw in studs?


ACK, each answer brings more questions... :wink:
Author:  Reed [ Mon Sep 27, 2004 3:27 pm ]
Post subject: 
It sounds to me like your fast idle screw and possibly the fast idle cam linkage are out of whack. Maybe these will help:

Image

Image

Image

I would adjust your carb to these specs and pay close attention to the adjustments for the choke and fast idle linkages.

Reed
Author:  Slant6Ram [ Mon Sep 27, 2004 4:17 pm ]
Post subject:  Holley $hit
I mean holley heck!

I've been tuning and retuning and adjusting and a- justing my holley 1920 for the past year.

I've deceided that it's just a really cheap carb with marginal adjusting features. I can make it run really good one day, and the next day, or next tank of gas or if it rains, it will require yet more adjustment.

I'm not crying, it gets me to work every day, and I've got the cold stalling completely worked out by bypassing the thermal vacuum advance switch with a little valve into the cab of my truck. I turn the valve off cold and on after about 10 minutes for better performance.

I can't let anyone else drive the truck for fear that it'll throw a fit and stall or something, but I'm so used to it now, that I can just pop the hood and lean it up or down to make it happy. :roll: I don't even burn my fingers anymore. :wink:

I'll put a bbd on eventually and I sure hope it helps gas mileage, because 13 mpg sucks! You're not the only one who has to fiddle.
Author:  Reed [ Mon Sep 27, 2004 9:58 pm ]
Post subject: 
In my opinion, the Holley 1920 is one of the simplest and most reliable carbs out there (fitting for the slant six...). I can be a little finicky to set up but once set it is very reliable. If you are using a remaufactured carb you really should make sure that you have a #61 or #63 main jet. Many remanufactured carbs get jetted very lean from the factory.
Author:  72swing [ Mon Sep 27, 2004 10:07 pm ]
Post subject:  1920
Quote:
Many remanufactured carbs get jetted very lean from the factory.

Heh,

Mine is running rich if anything. I am not sure what jet(s) are currently inside. I've heard a great deal (both bad and good) about this little carb but the general consencus is that the carter and even other holleys are better choices. Maybe I should tear it apart again and give it all another try...
Author:  Reed [ Mon Sep 27, 2004 10:21 pm ]
Post subject: 
I say tear it apart one more time and try again. These are my favorite carb for stock slants. I have always had good luck with them.
Author:  72swing [ Fri Oct 01, 2004 4:17 pm ]
Post subject:  New 1920, New problems
Hey /6ers... here's an update:

I bought a holley remanufactured 1920 from baxter auto parts here locally. The carb was flawlessly rebuilt, and installed/started perfectly. The idle is set correctly, it isn't dumping gas down the carb anymore, and milage has greatly improved! It was SO worth the 90 bucks or so, especially after the 4th "By the book" rebuild resulted in no better situation with the last carb!

New Problem: The engine's problems are all gone but one. The car still dies just off idle when it's not fully warmed up, and it stumbles in the same place even when warm and toasty. When cold the higher idle speed seems to eliminate it as a problem, but for the 10 minuites or so after the needle leaves the cold peg it's dangerous at intersections because it's as likely to die as to go. The problem mostly goes away when its warm to operating temp, but the hesitation remains just above idle. Is this a simple mixture screw issue? ACk! suggestions? I've tried tuning the old carb to death and I am a bit scared to F(@* up the new one.

JRC
Author:  Reed [ Fri Oct 01, 2004 8:11 pm ]
Post subject: 
Well, remanufactured carbs are notorious for not being adjusted properly and for being jetted way too lean. Unfortunately my advice is the same as it was before-- adjust the carb to the specs in the diagrams and make sure you have a #61 or #63 main jet in there.
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