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#1
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'79 304 Edelbrock carb problems vs Holley carbs?
My '79 CJ-5 304 seems to have fuel related problems. It is difficult to
start when the engine is cold; it turns over fine, but takes too long for the engine to start. Once running, it emits gassy fumes out of the exhaust side- pipes that make your clothes smell like gasoline while the top is off. I had a carb specialist try to adjust the carb, but it didn't help. The carb is an Edelbrock 4-barrel mounted on an Edelbrock hi-rise manifold. The motor has a street cam and headers. I was told that Edelbrock carbs do not work well with 304's, and to get a Holley Avenger truck carb with an electric choke. Before I drop the cash on a Holley, I would appreciate some advise to this problem. |
#2
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'79 304 Edelbrock carb problems vs Holley carbs?
Without knowing what size carb, choke or no choke, and which manifold, it is
hard to tell you what the problem could be. What I can tell you is that Edelbrock and Holley carbs are both set up from the factory with a general tune. This mean the carb may or may not need to be set up properly for your particular engine. In general, the Edelbrock carbs run too rich with the factory set up. Normally they will require a metering rod change, and maybe a jet change as well. You also don't specify the cam specs. When you say "street cam" that really doesn't tell anyone the specifics of your cam. The manifold cam also be a factor. Is it single or dual plane? Does it have the heat crossover to warm the engine properly? The last thing is, I like some of the features of the Avenger truck carbs, but a 300 cubic inch engine doesn't need a 670CFM carb. If they make a smaller version now, it would be cool, but again, you're probably going to have to do some jet and power valve changes to get the engine running the way it should. Remember, they call these carbs universal for a reason. Chris "Skyjacker" <u26190@uwe> wrote in message news:65d820af401df@uwe... > My '79 CJ-5 304 seems to have fuel related problems. It is difficult to > start when the engine is cold; it turns over fine, but takes too long for > the > engine to start. Once running, it emits gassy fumes out of the exhaust > side- > pipes that make your clothes smell like gasoline while the top is off. > > I had a carb specialist try to adjust the carb, but it didn't help. The > carb > is an Edelbrock 4-barrel mounted on an Edelbrock hi-rise manifold. The > motor > has a street cam and headers. > > I was told that Edelbrock carbs do not work well with 304's, and to get a > Holley Avenger truck carb with an electric choke. Before I drop the cash > on a > Holley, I would appreciate some advise to this problem. > |
#3
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'79 304 Edelbrock carb problems vs Holley carbs?
Any idea if the Edelbrock 600cfm 1405 Performer + Edelbrock 2131 manifold
will require a metering or jet change on a stock 360 '91 Grand Wagoneer ? Dave Milne, Scotland '91 Grand Wagoneer, '99 TJ "c" > wrote in message ... > Without knowing what size carb, choke or no choke, and which manifold, it is > hard to tell you what the problem could be. What I can tell you is that > Edelbrock and Holley carbs are both set up from the factory with a general > tune. This mean the carb may or may not need to be set up properly for your > particular engine. In general, the Edelbrock carbs run too rich with the > factory set up. Normally they will require a metering rod change, and maybe > a jet change as well. You also don't specify the cam specs. |
#4
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'79 304 Edelbrock carb problems vs Holley carbs?
You need a cam of at least 270 degrees, like AMC use in the sixties
to be able to use a four barrel: http://www.compcams.com/technical/Ca...6-07/16-19.pdf Stock muscle cars used 300 degrees of duration. God Bless America, Bill O|||||||O http://www.billhughes.com/ Dave Milne wrote: > > Any idea if the Edelbrock 600cfm 1405 Performer + Edelbrock 2131 manifold > will require a metering or jet change on a stock 360 '91 Grand Wagoneer ? > > Dave Milne, Scotland > '91 Grand Wagoneer, '99 TJ |
#5
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'79 304 Edelbrock carb problems vs Holley carbs?
I guess that means that any car that has a 426 Street Hemi in it isn't
considered a musclecar. http://www.426-hemi.com/hemi/info/tech/426/specs.htm Just a "little" 276/284 split duration cam in those grandma engines that had 2 4 barrel carbs from the factory. Also the 340/440 6-pack engines if those rich old grannies couldn't afford the hemi in their new car back then. And to think my whole life I though most grandmas would have enough power with 425 HP rated engine that actually made closer to 500 HP when you wound them a little higher. Those darn grannies!!! Chris "L.W.(Bill) Hughes III" > wrote in message ... > You need a cam of at least 270 degrees, like AMC use in the sixties > to be able to use a four barrel: > http://www.compcams.com/technical/Ca...6-07/16-19.pdf Stock muscle > cars used 300 degrees of duration. > God Bless America, Bill O|||||||O > http://www.billhughes.com/ > > Dave Milne wrote: >> >> Any idea if the Edelbrock 600cfm 1405 Performer + Edelbrock 2131 manifold >> will require a metering or jet change on a stock 360 '91 Grand Wagoneer ? >> >> Dave Milne, Scotland >> '91 Grand Wagoneer, '99 TJ |
#6
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'79 304 Edelbrock carb problems vs Holley carbs?
Need to correct myself here. I misread the cam specs. The duration was 276
in 1966-1967 and 284 after that. "c" > wrote in message ... >I guess that means that any car that has a 426 Street Hemi in it isn't >considered a musclecar. > > http://www.426-hemi.com/hemi/info/tech/426/specs.htm > > Just a "little" 276/284 split duration cam in those grandma engines that > had 2 4 barrel carbs from the factory. Also the 340/440 6-pack engines if > those rich old grannies couldn't afford the hemi in their new car back > then. And to think my whole life I though most grandmas would have enough > power with 425 HP rated engine that actually made closer to 500 HP when > you wound them a little higher. Those darn grannies!!! > > Chris > > "L.W.(Bill) Hughes III" > wrote in message > ... >> You need a cam of at least 270 degrees, like AMC use in the sixties >> to be able to use a four barrel: >> http://www.compcams.com/technical/Ca...6-07/16-19.pdf Stock muscle >> cars used 300 degrees of duration. >> God Bless America, Bill O|||||||O >> http://www.billhughes.com/ >> >> Dave Milne wrote: >>> >>> Any idea if the Edelbrock 600cfm 1405 Performer + Edelbrock 2131 >>> manifold >>> will require a metering or jet change on a stock 360 '91 Grand Wagoneer >>> ? >>> >>> Dave Milne, Scotland >>> '91 Grand Wagoneer, '99 TJ > > |
#7
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'79 304 Edelbrock carb problems vs Holley carbs?
Dave,
When the companies that make carb give them their initial settings from the factory, they take all kinds of compromised in to consideration. They don't know if the carb will be used on a large or small displacement engine, or if it will be used in hot or cold climate, high altitude, etc. They also don't know what other mods have been done to these engines. The baseline settings they give these carbs will allow them to run on most of the applications they will see, but they almost always require tuning to get them to be optimal. My guess would be that this carb would still be a little rich, but it is just a guess. I'm not saying it won't run, it will, and it will probably be pretty damn close to right. The metering rod system that Carter/Edelbrock uses will "adjust" the mixture based on engine vacuum. The rods are controlled by a piston and spring, similar to many other carbs. When the engine vacuum is low, the metering rod spring will start to overtake the vacuum pulling the piston down. The rods are tapered, and when they move up in the bore they are in, a smaller diameter of the rod will still be inside the main jet, effectively increasing the total main jet area that fuel can pass thru. If the engine runs too rich at high vacuum conditions, but is ok at low vacuum or wide open throttle, then you simply change the metering rod to on the has a larger diameter on the part of the rod that is in the jet at high vacuum conditions. It really is a simple process, and normally will only require 1 or 2 sets of rods to get the carb where you need it to be. Chris "Dave Milne" > wrote in message . uk... > Any idea if the Edelbrock 600cfm 1405 Performer + Edelbrock 2131 manifold > will require a metering or jet change on a stock 360 '91 Grand Wagoneer ? > > > Dave Milne, Scotland > '91 Grand Wagoneer, '99 TJ > "c" > wrote in message > ... >> Without knowing what size carb, choke or no choke, and which manifold, it > is >> hard to tell you what the problem could be. What I can tell you is that >> Edelbrock and Holley carbs are both set up from the factory with a >> general >> tune. This mean the carb may or may not need to be set up properly for > your >> particular engine. In general, the Edelbrock carbs run too rich with the >> factory set up. Normally they will require a metering rod change, and > maybe >> a jet change as well. You also don't specify the cam specs. > > > |
#8
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'79 304 Edelbrock carb problems vs Holley carbs?
Thanks. Looks like perhaps I should have ordered the calibration kit in
retrospect. Anyhow, after a 2 week wait, it has arrived so I'll fit at the weekend. Quite looking forward to it - my carb experience has been mainly with multiple SU's (single barrel downdraft) and the odd side draft Weber - never done anything on a 4 barrel like Holley or Edelbrock before. Dave Milne, Scotland '91 Grand Wagoneer, '99 TJ "c" > wrote in message ... > Dave, > > When the companies that make carb give them their initial settings from the > factory, they take all kinds of compromised in to consideration. They don't > know if the carb will be used on a large or small displacement engine, or if > it will be used in hot or cold climate, high altitude, etc. They also don't > know what other mods have been done to these engines. The baseline settings > they give these carbs will allow them to run on most of the applications > they will see, but they almost always require tuning to get them to be > optimal. My guess would be that this carb would still be a little rich, but > it is just a guess. I'm not saying it won't run, it will, and it will > probably be pretty damn close to right. > > The metering rod system that Carter/Edelbrock uses will "adjust" the mixture > based on engine vacuum. The rods are controlled by a piston and spring, > similar to many other carbs. When the engine vacuum is low, the metering rod > spring will start to overtake the vacuum pulling the piston down. The rods > are tapered, and when they move up in the bore they are in, a smaller > diameter of the rod will still be inside the main jet, effectively > increasing the total main jet area that fuel can pass thru. If the engine > runs too rich at high vacuum conditions, but is ok at low vacuum or wide > open throttle, then you simply change the metering rod to on the has a > larger diameter on the part of the rod that is in the jet at high vacuum > conditions. It really is a simple process, and normally will only require 1 > or 2 sets of rods to get the carb where you need it to be. > > Chris > > > "Dave Milne" > wrote in message > . uk... > > Any idea if the Edelbrock 600cfm 1405 Performer + Edelbrock 2131 manifold > > will require a metering or jet change on a stock 360 '91 Grand Wagoneer ? > > > > > > Dave Milne, Scotland > > '91 Grand Wagoneer, '99 TJ > > "c" > wrote in message > > ... > >> Without knowing what size carb, choke or no choke, and which manifold, it > > is > >> hard to tell you what the problem could be. What I can tell you is that > >> Edelbrock and Holley carbs are both set up from the factory with a > >> general > >> tune. This mean the carb may or may not need to be set up properly for > > your > >> particular engine. In general, the Edelbrock carbs run too rich with the > >> factory set up. Normally they will require a metering rod change, and > > maybe > >> a jet change as well. You also don't specify the cam specs. > > > > > > > > |
#9
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'79 304 Edelbrock carb problems vs Holley carbs?
Dave, you shouldn't have a problem tuning the Carter/Edelbrock carb, and
yes, they are basically the same carb inside. I believe the jets and rods interchange, but I'm not positive on that. I do know that the Edelbrock carb is heavily based on the Carter design. If you understand basic carb functioning, and what the rods and jets do for the mixture, it will be a simple process to get it dialed in. If you ruin in to problems, I'm sure we can get you going in the right direction. Also, there is a book available called Carter Carb Tuning. Most of it will apply to the Edelbrock as well. I had the book at one time, but loaned it out and never got it back. I do know that the book is very thorough. Chris "Dave Milne" > wrote in message . uk... > Thanks. Looks like perhaps I should have ordered the calibration kit in > retrospect. Anyhow, after a 2 week wait, it has arrived so I'll fit at the > weekend. > > Quite looking forward to it - my carb experience has been mainly with > multiple SU's (single barrel downdraft) and the odd side draft Weber - > never done anything on a 4 barrel like Holley or Edelbrock before. > > Dave Milne, Scotland > '91 Grand Wagoneer, '99 TJ > "c" > wrote in message > ... >> Dave, >> >> When the companies that make carb give them their initial settings from > the >> factory, they take all kinds of compromised in to consideration. They > don't >> know if the carb will be used on a large or small displacement engine, or > if >> it will be used in hot or cold climate, high altitude, etc. They also > don't >> know what other mods have been done to these engines. The baseline > settings >> they give these carbs will allow them to run on most of the applications >> they will see, but they almost always require tuning to get them to be >> optimal. My guess would be that this carb would still be a little rich, > but >> it is just a guess. I'm not saying it won't run, it will, and it will >> probably be pretty damn close to right. >> >> The metering rod system that Carter/Edelbrock uses will "adjust" the > mixture >> based on engine vacuum. The rods are controlled by a piston and spring, >> similar to many other carbs. When the engine vacuum is low, the metering > rod >> spring will start to overtake the vacuum pulling the piston down. The >> rods >> are tapered, and when they move up in the bore they are in, a smaller >> diameter of the rod will still be inside the main jet, effectively >> increasing the total main jet area that fuel can pass thru. If the engine >> runs too rich at high vacuum conditions, but is ok at low vacuum or wide >> open throttle, then you simply change the metering rod to on the has a >> larger diameter on the part of the rod that is in the jet at high vacuum >> conditions. It really is a simple process, and normally will only require > 1 >> or 2 sets of rods to get the carb where you need it to be. >> >> Chris >> >> >> "Dave Milne" > wrote in message >> . uk... >> > Any idea if the Edelbrock 600cfm 1405 Performer + Edelbrock 2131 > manifold >> > will require a metering or jet change on a stock 360 '91 Grand Wagoneer > ? >> > >> > >> > Dave Milne, Scotland >> > '91 Grand Wagoneer, '99 TJ >> > "c" > wrote in message >> > ... >> >> Without knowing what size carb, choke or no choke, and which manifold, > it >> > is >> >> hard to tell you what the problem could be. What I can tell you is >> >> that >> >> Edelbrock and Holley carbs are both set up from the factory with a >> >> general >> >> tune. This mean the carb may or may not need to be set up properly for >> > your >> >> particular engine. In general, the Edelbrock carbs run too rich with > the >> >> factory set up. Normally they will require a metering rod change, and >> > maybe >> >> a jet change as well. You also don't specify the cam specs. >> > >> > >> > >> >> > > |
#10
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'79 304 Edelbrock carb problems vs Holley carbs?
The rule of thumb was during the muscle car era, was any carburetor
that came form the factory needed to be jetted by about ten percent, of course that was too rich for the street and fouled plugs, but it was that little edge I had on everyone. God Bless America, Bill O|||||||O http://www.billhughes.com/ c wrote: > > Dave, > > When the companies that make carb give them their initial settings from the > factory, they take all kinds of compromised in to consideration. They don't > know if the carb will be used on a large or small displacement engine, or if > it will be used in hot or cold climate, high altitude, etc. They also don't > know what other mods have been done to these engines. The baseline settings > they give these carbs will allow them to run on most of the applications > they will see, but they almost always require tuning to get them to be > optimal. My guess would be that this carb would still be a little rich, but > it is just a guess. I'm not saying it won't run, it will, and it will > probably be pretty damn close to right. > > The metering rod system that Carter/Edelbrock uses will "adjust" the mixture > based on engine vacuum. The rods are controlled by a piston and spring, > similar to many other carbs. When the engine vacuum is low, the metering rod > spring will start to overtake the vacuum pulling the piston down. The rods > are tapered, and when they move up in the bore they are in, a smaller > diameter of the rod will still be inside the main jet, effectively > increasing the total main jet area that fuel can pass thru. If the engine > runs too rich at high vacuum conditions, but is ok at low vacuum or wide > open throttle, then you simply change the metering rod to on the has a > larger diameter on the part of the rod that is in the jet at high vacuum > conditions. It really is a simple process, and normally will only require 1 > or 2 sets of rods to get the carb where you need it to be. > > Chris |
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