carb issues

[PKRWUD]

I was referring to the new problem, but honestly, I don't see how the carb would create a shudder at cruise, either. Still, anything is possible. I think you should try and solve your new problem before digging into the old one.

[rwhite65]

Originally Posted by PKRWUD

I was referring to the new problem, but honestly, I don't see how the carb would create a shudder at cruise, either. Still, anything is possible. I think you should try and solve your new problem before digging into the old one.

I have broken just about everything you can with transmissions in the last ten years and I have had T.C.'s fail before. The original problem may have to do with the lock up, but my gut is telling me we were on to something with the carb. My knowledge of carbs has always been inferior, until recently when I decided I would learn all I could. PKRWUD, your knowledge of the carbs is incredible, so bear with me on this. Holley advises to use the vacuum gauge to figure out the proper power valve, as they also felt that was my problem when I called the tech line. I have not looked to see which power valve I have at the moment, but I am betting it is the 6.5, more then I need according to Holley. Plus, the new Holey book I bought talks about how the power valve can be responsible for surging under loads. You helped me get rid of the off idle stumble, and the only stumble (I called it a shudder) left is under a load, with my AOD. Makes sense to me that I am on to something there. I may rig the Vacuum gauge up in the car to confirm this.

The new problem....I took off work tomorrow so I can figure this thing out. I am basically going to start the F$($$ thing and let it run til the noise gets louder, or I find it, which ever comes first. If that fails, I am going to do hole shots up and down my street til it becomes apparent what has went bad.

Jester-
Other then the throttle not being perfectly smooth thru slow transitions, the car has been fantastic since I swapped the roller motor in last summer. Starts great, runs strong, idles quietly, but has a great lope to the cam. I had just finally decided I can outsmart the carb gods by fine tuning it, thinking I could get it perfect. One day the thing started making the weird noise, and within 20 minutes I had major power loss in the lower rpms. I will fix it tomorrow or break it, either way I am fed up with it
Ryan

[PKRWUD]

Originally Posted by rwhite65

I have broken just about everything you can with transmissions in the last ten years and I have had T.C.'s fail before. The original problem may have to do with the lock up, but my gut is telling me we were on to something with the carb. My knowledge of carbs has always been inferior, until recently when I decided I would learn all I could. PKRWUD, your knowledge of the carbs is incredible, so bear with me on this. Holley advises to use the vacuum gauge to figure out the proper power valve, as they also felt that was my problem when I called the tech line. I have not looked to see which power valve I have at the moment, but I am betting it is the 6.5, more then I need according to Holley. Plus, the new Holey book I bought talks about how the power valve can be responsible for surging under loads. You helped me get rid of the off idle stumble, and the only stumble (I called it a shudder) left is under a load, with my AOD. Makes sense to me that I am on to something there. I may rig the Vacuum gauge up in the car to confirm this.

I think the problem I'm having is in the terminology you're using. A stumble can be caused by a carb issue, a shudder tends to be caused by slippage in the driveline (for example, a burned flywheel will cause a shudder when you let out the clutch). It's all good, I just wasn't clear on what you meant.

Regardless, I agree that your first priority needs to be identifying your new problem. Just out of curiosity, do you have a vacuum advance on your Unilite?

[rwhite65]

Originally Posted by PKRWUD

Just out of curiosity, do you have a vacuum advance on your Unilite?

I do have a Vacuum advance.
Going out to work on it now,
Ryan

[PKRWUD]

Originally Posted by rwhite65

I do have a Vacuum advance.
Going out to work on it now,
Ryan

Try disconnecting and plugging the line, and see if there is any difference with your new problem.

[rwhite65]

Ok, so here is what I have so far. The #6 header tube about 1 inch from where it leaves the head has a 1.5-2 inch long crack in it, basically right at a bend. Using my official tool (old heater core hose) I have determined this was my "tapping noise" I heard. Even without using the hose, I can still hear it if I listen closely. I also found my header bolts needed some tightening as well.

I use to be able to hear my mech fuel pump before all this happened. Now I am having a hard time hearing its pumping noise. I am half wondering if it is going bad on me, so I may need to put my new carter pump on it. I am trying to hold off til I get a fuel pressure gauge and regulator mounted in the line, which nobody around here has in stock.

Oddly enough, when I try to adjust the idle/air mixture screw, the driver's side will kill the engine if I take it all the way in (about 1.5 turns). The passenger side however, can be closed all the way in and barely if any effects the idle of the car. Ok, so now I know I have a blockage. I also found that if I shoot carb cleaner in the primary idle air bleed (inside the choke horn area) for the passenger side, it made the idle speed up a little. Shooting it in the driver's side one made the idle die down and stumble.

The timing is at 12 degrees, set with both the timing light and a Vacuum gauge. Setting the timing anywhere else right now and it doesn’t run worth a crap. I also noticed my idle is now up to about 1,000-1100 rpms. I tried to get it back down under that where it normally would be, but it just wants to die then.

I am going out to yank the carb, try to clean it out and get it back on before work tonight at 7.

What is everyone' opinion on the headers? They were on the car when I bought it (full length) when it had a c-4. When I put the AOD in it, I had to heat them up near the collector and "tweak" them so they would clear my AOD. I can’t find anyone that makes full length for this combo. Should I get another set and tweak them, or just get a good set of shorty's?

Ryan

[PKRWUD]

Originally Posted by rwhite65

Oddly enough, when I try to adjust the idle/air mixture screw, the driver's side will kill the engine if I take it all the way in (about 1.5 turns). The passenger side however, can be closed all the way in and barely if any effects the idle of the car. Ok, so now I know I have a blockage. I also found that if I shoot carb cleaner in the primary idle air bleed (inside the choke horn area) for the passenger side, it made the idle speed up a little. Shooting it in the driver's side one made the idle die down and stumble.

Okay, you are having the opposite problem as Brian is. He has a clogged idle air bleed, but you have a clog/restriction in the idle well, on the passenger side of the primary metering block. You want to remove the mixture screws, and spray Brakleen (green can) in the opening where the passenger side primary jet is. Compare it with the other side, and when they both spray out the same on the other side, you should be good.

Originally Posted by rwhite65

The timing is at 12 degrees, set with both the timing light and a Vacuum gauge. Setting the timing anywhere else right now and it doesn’t run worth a crap. I also noticed my idle is now up to about 1,000-1100 rpms. I tried to get it back down under that where it normally would be, but it just wants to die then.

Just to clarify, adjust the idle mixture and timing with a vacuum gauge, and then turn down the idle speed with the idle speed screw.