Carb or Ignition Problem
08-28-2001, 10:25 AM
#1
Team Owner
Thread Starter
Carb or Ignition Problem
I have a problem when going full throttle on my 71 with a ZZ4 and a rebuilt Q-jet. The engine has almost 2000 miles on it and this problem just started happening. Normal acceleration and driving are just fine but when I go to the floor the engine starts spitting and sputtering like its either loosing furel or the ignition is cutting out. I think it is a fuel problem because if I let up just a little on the gas pedal the engine runs fine. I have a MSD tach drive distributor with a blaster 2 coil mounted on the intake at the old engines stock location and a MSD 6AL ignition box mounted behind the expansion tank on the right hand wheel well. My initial advance is 10 degrees BTC with the vacuum advanced disconneded and pluged and total advance is 36 degrees @ 3200 rpm. I am going to take the fuel filter out today and check it out and recheck my timing. All components are brand new execpt for the carb...rebuilt. Lars if you see this how much would you charge to take a look at my Q-jet and jet it for the ZZ4? I want to take the car to the track September 12th but I need this fixed first so I don't embarrass myself. The car has run fine up to this point. It has only done it the past few time I have driven it. It does it when it is cold or hot.
Thanks
John :cry
Thanks
John :cry
08-28-2001, 01:52 PM
#2
Tech Contributor
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Re: Carb or Ignition Problem (theandies)
John -
Caught your post here and thought I'd throw in a few comments....
You correctly assume that the symptoms you describe can be related to ignition or fuel. I always like to start with the ignition system first, since this is the easiest to correct and tune.... But it sounds like you have the timing and total timing correctly set, and your components are of good quality. Normally, I would recommend you assure that your points are of good quality, that the dwell is correctly set at 30 -31, make sure the condenser is good and fresh, and assure that the coil is fairly new with adequate voltage being applied to the system.
On the Q-Jet, the most common problem when the car falls on its face at wide open throttle is the secondary airvalve spring windup adjustment. Many carb builders think that performance will improve if the secondaries open quicker, and they set the spring tension very loose (at about 1/2 turn or less). This is not the case: If the Q-Jet secondaries are allowed to pop open too soon, the car will go flat, spit, sputter, and loose power as soon as the pedal goes to the metal. I recommend a secondary airvalve spring windup of 7/8 turn as an initial setting. If you need any direction on how to set this, please let me know, and I'll post some instructions.
Incorrect float level and plugged fuel filter will also cause the symptoms you describe. Your float level should be set at about 3/8". Later model Q-Jets use a lower float level of about .420", and many carb builders use this float level on the early carbs. If you drop the float level on a '71 down to .420, the carb will lean out and sputter at wide open throttle.
Inadequate fuel pressure will cause what you describe, but not usually instantly when you floor it: Inadequate fuel pressure/bad fuel pump will usually cause the car to go flat about half-way into second gear during WOT acceleration. Initial acceleration through first gear is usually normal.
I also commonly see an in-line fuel filter installed when the carb has the in-carb filter in it. If you have two fuel filters installed in this fashion, the pressure drop through your line will be excessive, and you will run into a fuel starvation issue when you go to WOT.
Finally, I very often see carb builders put extremely rich (thin) secondary metering rods into performance applications, believing that richer is always better. in fact, it is very easy to go too rich on the secondary side metering, and this will cause a rich sputter/bog upon secondary opening. Have someone follow you when you go to wide open throttle and observe if you're puking black smoke out the tailpipes when the secondaries open. If you are, you need to install fatter rods.
This should give you a few things to keep you entertained for a short while.... Do contact me if I can assist in any way.
Caught your post here and thought I'd throw in a few comments....
You correctly assume that the symptoms you describe can be related to ignition or fuel. I always like to start with the ignition system first, since this is the easiest to correct and tune.... But it sounds like you have the timing and total timing correctly set, and your components are of good quality. Normally, I would recommend you assure that your points are of good quality, that the dwell is correctly set at 30 -31, make sure the condenser is good and fresh, and assure that the coil is fairly new with adequate voltage being applied to the system.
On the Q-Jet, the most common problem when the car falls on its face at wide open throttle is the secondary airvalve spring windup adjustment. Many carb builders think that performance will improve if the secondaries open quicker, and they set the spring tension very loose (at about 1/2 turn or less). This is not the case: If the Q-Jet secondaries are allowed to pop open too soon, the car will go flat, spit, sputter, and loose power as soon as the pedal goes to the metal. I recommend a secondary airvalve spring windup of 7/8 turn as an initial setting. If you need any direction on how to set this, please let me know, and I'll post some instructions.
Incorrect float level and plugged fuel filter will also cause the symptoms you describe. Your float level should be set at about 3/8". Later model Q-Jets use a lower float level of about .420", and many carb builders use this float level on the early carbs. If you drop the float level on a '71 down to .420, the carb will lean out and sputter at wide open throttle.
Inadequate fuel pressure will cause what you describe, but not usually instantly when you floor it: Inadequate fuel pressure/bad fuel pump will usually cause the car to go flat about half-way into second gear during WOT acceleration. Initial acceleration through first gear is usually normal.
I also commonly see an in-line fuel filter installed when the carb has the in-carb filter in it. If you have two fuel filters installed in this fashion, the pressure drop through your line will be excessive, and you will run into a fuel starvation issue when you go to WOT.
Finally, I very often see carb builders put extremely rich (thin) secondary metering rods into performance applications, believing that richer is always better. in fact, it is very easy to go too rich on the secondary side metering, and this will cause a rich sputter/bog upon secondary opening. Have someone follow you when you go to wide open throttle and observe if you're puking black smoke out the tailpipes when the secondaries open. If you are, you need to install fatter rods.
This should give you a few things to keep you entertained for a short while.... Do contact me if I can assist in any way.
08-28-2001, 03:52 PM
#3
Team Owner
Thread Starter
Re: Carb or Ignition Problem (lars)
Lars,
Thanks for the advice and what you said will keep me entertained next weekend. I was checking my timing and while I was leting the car warm up to operating temprature I noticed that every once in a while my alternator would make a clicking sound...like the bearing is going out. My amp meter looks ok though. I ordered a new one and it should be in tomorrow, unfortunately I have to work all day and my next day off isn't until Sunday. That is when I plan on doing your suggestions. As far as my fuel system goes I have a new stock style fuel pump and I only have the in-carb fuel filter. My distrbutor is a MSD unit with magnetic triggering (no points) in the cap and it is brand new...installed when I put the ZZ4 in this spring. My timing is correct, I checked it this morning. I pulled a spark plug to check it out and it still look brand new (engine has almost 2000 miles on it). What color should I see if the mixture is off at WOT? I also noticed a small fuel stain on the front of my intake and it looks as if the upper gasket on the front of the carb is seeping fuel (no puddle of fuel) ......what is that? Float level too high? Instructions on how to adjust the secondary airvalve spring and float level would be great at your conveniance. I would like to tackle this problem myself but if all else fails and we figure it out to be the carb, then I may send it to you to tune if you don't mind. I don't know much about Q-jets...all my experiance is with Hollys but I don't like them because of leaks. My friend 69 Camaro actually caught on fire one night because his Holly leaked!!!! Any adjustment you recomment on the Q-jet for the ZZ4 would be greatly apprciated. I will have a friend follow me to see what the exhaust looks like (I'll take it to work this week).
Thanks again for your responce.
John
P.S. My fuel filter looks good but I am going to change it out when I change my alternator just to be on the safe side. One more thing. Do you know if GM used a fuel tank pickup filter (AKA sock) in 71 Vettes and could that be a WOT problem?
Thanks for the advice and what you said will keep me entertained next weekend. I was checking my timing and while I was leting the car warm up to operating temprature I noticed that every once in a while my alternator would make a clicking sound...like the bearing is going out. My amp meter looks ok though. I ordered a new one and it should be in tomorrow, unfortunately I have to work all day and my next day off isn't until Sunday. That is when I plan on doing your suggestions. As far as my fuel system goes I have a new stock style fuel pump and I only have the in-carb fuel filter. My distrbutor is a MSD unit with magnetic triggering (no points) in the cap and it is brand new...installed when I put the ZZ4 in this spring. My timing is correct, I checked it this morning. I pulled a spark plug to check it out and it still look brand new (engine has almost 2000 miles on it). What color should I see if the mixture is off at WOT? I also noticed a small fuel stain on the front of my intake and it looks as if the upper gasket on the front of the carb is seeping fuel (no puddle of fuel) ......what is that? Float level too high? Instructions on how to adjust the secondary airvalve spring and float level would be great at your conveniance. I would like to tackle this problem myself but if all else fails and we figure it out to be the carb, then I may send it to you to tune if you don't mind. I don't know much about Q-jets...all my experiance is with Hollys but I don't like them because of leaks. My friend 69 Camaro actually caught on fire one night because his Holly leaked!!!! Any adjustment you recomment on the Q-jet for the ZZ4 would be greatly apprciated. I will have a friend follow me to see what the exhaust looks like (I'll take it to work this week).
Thanks again for your responce.
John
P.S. My fuel filter looks good but I am going to change it out when I change my alternator just to be on the safe side. One more thing. Do you know if GM used a fuel tank pickup filter (AKA sock) in 71 Vettes and could that be a WOT problem?
08-28-2001, 04:37 PM
#4
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Re: Carb or Ignition Problem (theandies)
John -
On your secondary airvalve, check & adjust the following (this is the most probable cause, and should be the first thing you do):
The airvalve spring and its adjustment are located on the passenger side of the carb, rear, top, by the lever on the airvalve that the choke pulloff rod is attached to. If you look at the area of the carb right by the lever, you will see a small, slotted head screw. Now, if you look up underneath the area where the screw and lever are located (it helps to use a small mirror and a flashlight), you will see a small allen head screw. Right next to the allen head screw, you will see the spring. You will also notice that the end of the spring is hooked around a thin, steel pin.
With the mirror layed out underneath the area so you can see the spring and its engagement with the pin, slip a small flat blade screwdriver into the slotted screw and hold it in place. With your other hand, engage an allen wrench into the allen screw underneath and loosen the allen screw about 1/4 turn. The allen screw is a lock screw for the slotted screw. Remember: rightie-tightie, leftie-loosie, except when it's upside down.... make sure you turn the allen screw the correct direction to loosen it so you don't try stripping out the casting...
Once the allen screw is loosened about 1/4 turn, the slotted screw is free to turn. The reason you are holding the screwdriver in the screw is to prevent the screw from suddenly turning from spring tension once the allen screw is loosened. With the allen screw loosened, slowly allow the slotted screw to unwind from spring tension. Count and note how far the screw turns before you can see the spring break contact with the steel pin. If the carb is correctly adjusted, it should be 3/4 to 7/8 turn of the slotted head screw. Once contact is broken, observe the spring in the mirror, and turn the screw until the spring just barely touches the pin. Now, wind the screw up 7/8 turn, hold it there, and snug up the allen screw underneath to lock things in place.
This will assure that the secondaries do not flop open too soon, and may very well solve your problem. Try this first before you go chasing all the other stuff.
What type of spark plugs are you running? If you're running one of the exotic metalic plugs (like the platinums), you will not be able to get a good spark plug "reading" by pulling the plugs to check mixture. The platinum plugs run clean even under bad mixture conditions. You must install a set of standard plugs in order to get a valid plug reading. With standard plugs, a few WOT runs on the engine should produce a very light tan coating on the ceramic nose of the plug. If it's pure white, you may be on the lean side (which will happen if the secondaries are popping open too soon). If its dark or sooty, you're rich.
It is not uncommon for the air horn gasket on a Q-Jet to "seep" just a little: under hard acceleration, braking, and cornering the fuel in the bowl will slosh around a bit and it will saturate the gasket and make it slightly moist. However, it should not be getting fuel saturated if you simply start the car and let it sit and idle. If this is occurring, your float level is too high for one of many reasons. I can give you a list of reasons if this is a concern.
Yes, GM used a pickup "sock" on the '71, and a plugged sock will cause the problem you indicate. However, the problem will usually not only occur when you go to WOT: You can usually get the problem to occur when you lug the car up a long hill: without getting into the secondary side, load the car up running on the primaries only. Fuel consumption in this mode will be high enough that a restriction caused by a plugged sock withh soon cause the engine to lean out and fall on its face, even without getting into the secondaries.
If the problem occurs instantaneously when you smash the pedal to the floor to open the secondaries, you most likely do NOT have a fuel supply problem: when you have a fuel supply problem, the car runs fine for the first few seconds until it starves itself of the fuel in the fuel bowl. Then it falls on its face.
Let me know how you make out....
On your secondary airvalve, check & adjust the following (this is the most probable cause, and should be the first thing you do):
The airvalve spring and its adjustment are located on the passenger side of the carb, rear, top, by the lever on the airvalve that the choke pulloff rod is attached to. If you look at the area of the carb right by the lever, you will see a small, slotted head screw. Now, if you look up underneath the area where the screw and lever are located (it helps to use a small mirror and a flashlight), you will see a small allen head screw. Right next to the allen head screw, you will see the spring. You will also notice that the end of the spring is hooked around a thin, steel pin.
With the mirror layed out underneath the area so you can see the spring and its engagement with the pin, slip a small flat blade screwdriver into the slotted screw and hold it in place. With your other hand, engage an allen wrench into the allen screw underneath and loosen the allen screw about 1/4 turn. The allen screw is a lock screw for the slotted screw. Remember: rightie-tightie, leftie-loosie, except when it's upside down.... make sure you turn the allen screw the correct direction to loosen it so you don't try stripping out the casting...
Once the allen screw is loosened about 1/4 turn, the slotted screw is free to turn. The reason you are holding the screwdriver in the screw is to prevent the screw from suddenly turning from spring tension once the allen screw is loosened. With the allen screw loosened, slowly allow the slotted screw to unwind from spring tension. Count and note how far the screw turns before you can see the spring break contact with the steel pin. If the carb is correctly adjusted, it should be 3/4 to 7/8 turn of the slotted head screw. Once contact is broken, observe the spring in the mirror, and turn the screw until the spring just barely touches the pin. Now, wind the screw up 7/8 turn, hold it there, and snug up the allen screw underneath to lock things in place.
This will assure that the secondaries do not flop open too soon, and may very well solve your problem. Try this first before you go chasing all the other stuff.
What type of spark plugs are you running? If you're running one of the exotic metalic plugs (like the platinums), you will not be able to get a good spark plug "reading" by pulling the plugs to check mixture. The platinum plugs run clean even under bad mixture conditions. You must install a set of standard plugs in order to get a valid plug reading. With standard plugs, a few WOT runs on the engine should produce a very light tan coating on the ceramic nose of the plug. If it's pure white, you may be on the lean side (which will happen if the secondaries are popping open too soon). If its dark or sooty, you're rich.
It is not uncommon for the air horn gasket on a Q-Jet to "seep" just a little: under hard acceleration, braking, and cornering the fuel in the bowl will slosh around a bit and it will saturate the gasket and make it slightly moist. However, it should not be getting fuel saturated if you simply start the car and let it sit and idle. If this is occurring, your float level is too high for one of many reasons. I can give you a list of reasons if this is a concern.
Yes, GM used a pickup "sock" on the '71, and a plugged sock will cause the problem you indicate. However, the problem will usually not only occur when you go to WOT: You can usually get the problem to occur when you lug the car up a long hill: without getting into the secondary side, load the car up running on the primaries only. Fuel consumption in this mode will be high enough that a restriction caused by a plugged sock withh soon cause the engine to lean out and fall on its face, even without getting into the secondaries.
If the problem occurs instantaneously when you smash the pedal to the floor to open the secondaries, you most likely do NOT have a fuel supply problem: when you have a fuel supply problem, the car runs fine for the first few seconds until it starves itself of the fuel in the fuel bowl. Then it falls on its face.
Let me know how you make out....
08-28-2001, 04:53 PM
#5
Le Mans Master
Re: Carb or Ignition Problem (lars)
lars,
I had my '80 L48 dyno'd this weekend and the shop mgr said it was running way too lean at WOT. Around 13.1:1. He suggested replacement of the secondary metering rods (richen it up a little). I suspect I am running stock metering rods on my '80 Quadrajet. What do you recommend? Also, My distributor isn't dialed in yet. I have about 10 degrees initial but don't know when it is 'all in'. Car will be out of service for next 2-3 weeks while I swap 700R4 and 3.55s in. Would like to get the distributor closer to optimal as well as that secondary metering rods.
I had my '80 L48 dyno'd this weekend and the shop mgr said it was running way too lean at WOT. Around 13.1:1. He suggested replacement of the secondary metering rods (richen it up a little). I suspect I am running stock metering rods on my '80 Quadrajet. What do you recommend? Also, My distributor isn't dialed in yet. I have about 10 degrees initial but don't know when it is 'all in'. Car will be out of service for next 2-3 weeks while I swap 700R4 and 3.55s in. Would like to get the distributor closer to optimal as well as that secondary metering rods.
08-28-2001, 05:30 PM
#6
Tech Contributor
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Re: Carb or Ignition Problem (TedH)
Ted -
Check your secondary rods and see if they are the correct ones for your car: the '80 Vette should have "CH" secondary rods. This is a rod with a .057" diameter power tip.
The CH rod is a relatively lean rod compared to other rods used on earlier model Vettes. Although many different rods were used in Vettes, a common performance rod found in many 350s is the "DA" rod. This is a rod with a .0443 diameter tip. This would richen you up a tad without getting too extreme.
Many of the high performance Chevy engines of the early to late '60s used the "AX" rod. This is about as rich as the Vettes were ever set up on the secondary side, and it is an .040" diameter rod.
A word of caution, however, when doing secondary jetting (rod changes). The Q-Jet is what I call a "variable CFM carb." With its secondary airvalve, it can produce and deliver any cfm requirement up to about 750 cfm. Thus, you can put a Q-Jet on a 6-cylinder, and the car will not be over-carbureted. Even on a 350, 750 cfm is more capacity than the engine uses during most of its rpm range. Thus, we see, the Q-Jet on a 350 spends most of its time and effort, even at WOT, on the primary side.The secondary side becomes a compliment to the primary side, but the primary side is doing the majority of the metering up through the rpm range. Only when the rpm and air volume is really getting up there does the secondary side have a majority effect.
Thus, the primary jetting is actually more critical than the secondary jetting for the majority of the time. You cannot "make up" incorrect jetting on the primary side through a rod change on the secondary side. Your primary jetting needs to be correct first, and then you can compliment this jetting and airflow through correct secondary metering. Only in this way will you produce maximum, smooth power up through the range.
If you have access to a printout of your dyno run, take a look at your mixture when the engine is under load and coming up through the lower rpm range. In the lower range, the secondaries are not contributing, since airflow is insufficient to open the secondary airvalve. If your mixture is lean in the lower rpm range, you need to richen up your primary jetting first before tackling the secondary rods. If your mixture is okay at the low end, and then leans out as the secondaries start to contribute, you can benefit from a secondary rod change.
Here's a tuning trick I recommend if you have a little time on your hands on a Saturday....
Find a road where you can make some wide open runs over a constant distance, say a few hundred feet, without anybody hassling you. You'll also need a stopwatch, a performance computer, or a good eye on the speedometer.
Engage the secondary lockout lever on the passenger side of the carb. Wire it in place so the secondaries cannot open at all. With the secondaries locked shut, run the car a couple of times through your distance and note the speed at the end of the distance or the time to distance. Make sure you're getting consistent numbers.
Now, pop your main jets out and install a set 2 sizes larger. Keep the secondaries locked shut. Make your distance run again and see what happens to your time and/or speed to distance. If the performance improves, you need the richer mixture on the primary side. If performance does not improve, or if it deteriorates, your primary side was okay (and you may even want to try leaning it out 2 sizes for a third run).
Once you have the primary side optimized, you can unlock the secondaries and run the car again with a couple of different secondary rods. You can thus optimize the primary and the secondary side independently of each other. They will thus compliment each other perfectly for the most ultimate performance potential.
Feel free to contact me with any questions on this procedure.
Check your secondary rods and see if they are the correct ones for your car: the '80 Vette should have "CH" secondary rods. This is a rod with a .057" diameter power tip.
The CH rod is a relatively lean rod compared to other rods used on earlier model Vettes. Although many different rods were used in Vettes, a common performance rod found in many 350s is the "DA" rod. This is a rod with a .0443 diameter tip. This would richen you up a tad without getting too extreme.
Many of the high performance Chevy engines of the early to late '60s used the "AX" rod. This is about as rich as the Vettes were ever set up on the secondary side, and it is an .040" diameter rod.
A word of caution, however, when doing secondary jetting (rod changes). The Q-Jet is what I call a "variable CFM carb." With its secondary airvalve, it can produce and deliver any cfm requirement up to about 750 cfm. Thus, you can put a Q-Jet on a 6-cylinder, and the car will not be over-carbureted. Even on a 350, 750 cfm is more capacity than the engine uses during most of its rpm range. Thus, we see, the Q-Jet on a 350 spends most of its time and effort, even at WOT, on the primary side.The secondary side becomes a compliment to the primary side, but the primary side is doing the majority of the metering up through the rpm range. Only when the rpm and air volume is really getting up there does the secondary side have a majority effect.
Thus, the primary jetting is actually more critical than the secondary jetting for the majority of the time. You cannot "make up" incorrect jetting on the primary side through a rod change on the secondary side. Your primary jetting needs to be correct first, and then you can compliment this jetting and airflow through correct secondary metering. Only in this way will you produce maximum, smooth power up through the range.
If you have access to a printout of your dyno run, take a look at your mixture when the engine is under load and coming up through the lower rpm range. In the lower range, the secondaries are not contributing, since airflow is insufficient to open the secondary airvalve. If your mixture is lean in the lower rpm range, you need to richen up your primary jetting first before tackling the secondary rods. If your mixture is okay at the low end, and then leans out as the secondaries start to contribute, you can benefit from a secondary rod change.
Here's a tuning trick I recommend if you have a little time on your hands on a Saturday....
Find a road where you can make some wide open runs over a constant distance, say a few hundred feet, without anybody hassling you. You'll also need a stopwatch, a performance computer, or a good eye on the speedometer.
Engage the secondary lockout lever on the passenger side of the carb. Wire it in place so the secondaries cannot open at all. With the secondaries locked shut, run the car a couple of times through your distance and note the speed at the end of the distance or the time to distance. Make sure you're getting consistent numbers.
Now, pop your main jets out and install a set 2 sizes larger. Keep the secondaries locked shut. Make your distance run again and see what happens to your time and/or speed to distance. If the performance improves, you need the richer mixture on the primary side. If performance does not improve, or if it deteriorates, your primary side was okay (and you may even want to try leaning it out 2 sizes for a third run).
Once you have the primary side optimized, you can unlock the secondaries and run the car again with a couple of different secondary rods. You can thus optimize the primary and the secondary side independently of each other. They will thus compliment each other perfectly for the most ultimate performance potential.
Feel free to contact me with any questions on this procedure.
08-28-2001, 05:34 PM
#7
Team Owner
Thread Starter
Re: Carb or Ignition Problem (lars)
I found the problem. I took an old Q-jet I had in a box and was looking it over and noticed that there is a screw on the secondary metering rods. I look at my "rebuilt" Q-jet and the screw was missing. I pushed the throttle to WOT and the metering rods didn't even move! Bubba must have rebuilt this carb. I got it through CC before I came across the forum. I took the screw off the old cab and installed it on the "Bubba rebuild" and took it for a test run....WOW what a differance. :eek: No stumble and in second it will lay down rubber as long as you stay in it. Now for my next question. As I was playing I removed the secondary rods and they are marked CM. The rods that are in the old carb are marked BA. Which rods would be better for my ZZ4?
Thanks guys for all the responces and also I would still like the adjusment procedures so keep them coming.
John
Thanks guys for all the responces and also I would still like the adjusment procedures so keep them coming.
John
08-28-2001, 05:43 PM
#8
Tech Contributor
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Re: Carb or Ignition Problem (theandies)
The "BA" rods have a .057" diameter tip, with a medium length tip. The CM rods have a .040" diamater tip, also with a medium length. Thus, the CM rods will run quite a bit richer and may work better for your ZZ4. .040" rods were used in a lot of the '60s high performance Vette engines, whereas use of .057" rods started in '74 and ran through 1980 in the low-compression smogger engines. This is not to say that your ZZ4 may not respond well to a leaner setting... you just have to try it and see what your engine wants.
08-28-2001, 05:46 PM
#9
Team Owner
Thread Starter
Re: Carb or Ignition Problem (lars)
Thanks,
I'll play around with them. Where can you pick up different rods or are they not made anymore?
You're the man! :cheers:
John
[Modified by theandies, 3:46 PM 8/28/2001]
I'll play around with them. Where can you pick up different rods or are they not made anymore?
You're the man! :cheers:
John
[Modified by theandies, 3:46 PM 8/28/2001]
08-29-2001, 10:21 AM
#10
Tech Contributor
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Re: Carb or Ignition Problem (theandies)
Rods are available from two sources:
1. My stash of parts in my basement
2. Edelbrock
Edelbrock is currently offering the following secondary rods for the Q-Jet:
CC .030" Part Number 1950
CE .041" Part Number 1951
CK .0527" Part Number 1952
AY .0567" Part Number 1953
CL .0667" Part Number 1954
This is a pretty abbreviated rod list compared to what GM once offered, but it does give you a good range for tuning purposes, especially if you get the primary side of the carb set up right to start with.
Price is $6.86 a pair. Any NAPA store can get Edelbrock parts, and I believe other chain outlets such as Advance, Big A, and others can also get the stuff. You can also mail order through Summit.
1. My stash of parts in my basement
2. Edelbrock
Edelbrock is currently offering the following secondary rods for the Q-Jet:
CC .030" Part Number 1950
CE .041" Part Number 1951
CK .0527" Part Number 1952
AY .0567" Part Number 1953
CL .0667" Part Number 1954
This is a pretty abbreviated rod list compared to what GM once offered, but it does give you a good range for tuning purposes, especially if you get the primary side of the carb set up right to start with.
Price is $6.86 a pair. Any NAPA store can get Edelbrock parts, and I believe other chain outlets such as Advance, Big A, and others can also get the stuff. You can also mail order through Summit.
08-29-2001, 11:35 AM
#11
Team Owner
Thread Starter
Re: Carb or Ignition Problem (lars)
Thanks for all your help. If I am ever in Denver I'll buy you a beer :cheers:
I will setup the primaries like you said then start playing with the secondaries as soon as I find the time. My son and wife have been out of town for a week and I got some free time to work on the Vette while they were gone. As usual, when they get home the Vette only gets driven unless something drastic happens to it. My 19 month old son is a handfull as you can imagine but he loves "helping" me in the garage.
This is him helping me install my ZZ4 this spring.
Thanks again
John
I will setup the primaries like you said then start playing with the secondaries as soon as I find the time. My son and wife have been out of town for a week and I got some free time to work on the Vette while they were gone. As usual, when they get home the Vette only gets driven unless something drastic happens to it. My 19 month old son is a handfull as you can imagine but he loves "helping" me in the garage.
This is him helping me install my ZZ4 this spring.
Thanks again
John
