Re-jetting the Carter 750's
#1
Re-jetting the Carter 750's
Well I finally get to re-jet my carbs down somewhat.
I pulled both carbs apart and a metering rod was broke on the rear carb. Not sure how that happened but I'm going to install all new jets and rods similar to what Edelbrock has in their 600 cfm performers.
Friends always told me they could smell the exhaust as being somewhat rich which I could never seem to adjust correctly hence the metering rod. Cam II fuel has that distinctive smell anyway.
I hope it'll run a little better. Tends to bog when the second carb kicks in unless I stomp on it, then I lose traction
I pulled both carbs apart and a metering rod was broke on the rear carb. Not sure how that happened but I'm going to install all new jets and rods similar to what Edelbrock has in their 600 cfm performers.
Friends always told me they could smell the exhaust as being somewhat rich which I could never seem to adjust correctly hence the metering rod. Cam II fuel has that distinctive smell anyway.
I hope it'll run a little better. Tends to bog when the second carb kicks in unless I stomp on it, then I lose traction
Last edited by 67Olds442X2; February 3rd, 2012 at 10:45 AM.
#3
That jet and metering rod kit comes with different springs for the power pistons, if it's smells real rich at idle you might want to install lighter springs if that what they say to do for engine with low vacuum @ idle.
You might want to turn the fuel screw on the front of the carb in a little to lean out idle and open the air screw a little.
Make sure your primary throttle blades aren't open too much, many people screw in the idle set screw too much to raise their idle instead of adjusting the fuel/air screws on the front of the carb and putting the right springs in under the power pistons to get it to idle right.
I have a Barry Grant Mighty Demon on my car and these carbs are notorious for having an overly rich idle. The instructions tell you to never close the idle mixer screws more than 1 1/2 out, I run mine at 3/4 turn out it doesn't have that overly rich gas smell when you stand behind the car like it did when it was adjusted the way they tell you to do it.
You might want to turn the fuel screw on the front of the carb in a little to lean out idle and open the air screw a little.
Make sure your primary throttle blades aren't open too much, many people screw in the idle set screw too much to raise their idle instead of adjusting the fuel/air screws on the front of the carb and putting the right springs in under the power pistons to get it to idle right.
I have a Barry Grant Mighty Demon on my car and these carbs are notorious for having an overly rich idle. The instructions tell you to never close the idle mixer screws more than 1 1/2 out, I run mine at 3/4 turn out it doesn't have that overly rich gas smell when you stand behind the car like it did when it was adjusted the way they tell you to do it.
#4
I have a Barry Grant Mighty Demon on my car and these carbs are notorious for having an overly rich idle. The instructions tell you to never close the idle mixer screws more than 1 1/2 out, I run mine at 3/4 turn out it doesn't have that overly rich gas smell when you stand behind the car like it did when it was adjusted the way they tell you to do it.
I know the Carter is much different than a Holley but it would seem that the principle is the same...have the throttle plates open 1/16" and use the A/F mixture screws and jet it to adjust the idle baseline. IDK...maybe not
Steve
#5
I ordered some new metering rods and primary jets. Also I'm getting some springs to go with them. I'm leaving the secondary jets as is for now. I have a feeling that the rod that broke wasn't in the jet at all and that would cause the richness. I'll try setting the idle screws with the carbs out that way I can see how far open the blades are and set the speed with the mixture screws.
Both carbs have 4 holes on the accelerator pump arm and I've played with various options. Will check it out again after putting the carbs back together. Bad enough to set one carb but two
Here's a vid of the car at idle before I decided to pull the carbs apart. Almost sounds as if something is not quite right.
http://www.youtube.com/watch?v=T7Ug1F3wpls
Both carbs have 4 holes on the accelerator pump arm and I've played with various options. Will check it out again after putting the carbs back together. Bad enough to set one carb but two
Here's a vid of the car at idle before I decided to pull the carbs apart. Almost sounds as if something is not quite right.
http://www.youtube.com/watch?v=T7Ug1F3wpls
#7
those look good, real good! i think thats a good call on fixing the broken secondary rod, baselining the adjustments and starting over... very good call. i don't see how the rod would've broken if it was in the jet.
i like the afb carbs, i've always been able to make good power with them and still have good economy too. i'm glad that edelbrock kept that line alive...
i see that those are 750 cfm carbs, you may need to go to 600's... thats a lot of carb for a .030 over 455, the iron heads tell me that the compression is probably under 10:1 or thereabouts. smaller carbs would probably improve your low speed drivability...
i like the afb carbs, i've always been able to make good power with them and still have good economy too. i'm glad that edelbrock kept that line alive...
i see that those are 750 cfm carbs, you may need to go to 600's... thats a lot of carb for a .030 over 455, the iron heads tell me that the compression is probably under 10:1 or thereabouts. smaller carbs would probably improve your low speed drivability...
Last edited by bigD; February 8th, 2012 at 05:33 AM. Reason: added content
#8
bigD his heads were cut, block decked. That motor is making some serious power, especially with cam he's got and 1.7 rockers. He know's he needs to go down a bit on the carbs though...
Dan, those things look B-A! What made you think to paint them? I love it!
Dan, those things look B-A! What made you think to paint them? I love it!
#9
One day I'll get smaller carbs, I'm re-jetting them down a bit probably won't be enough but oh well. My compression is some where around 10.75:1, still have too much carb.
I had painted the carbs silver before and I had some bronze carb paint left over from doing my QJ carb. I painted the spacers also, looks a lot cleaner. Now if I had just painted the motor bronze.
I had painted the carbs silver before and I had some bronze carb paint left over from doing my QJ carb. I painted the spacers also, looks a lot cleaner. Now if I had just painted the motor bronze.
#10
thats cool... have you had much trouble with detonation? i like the looks of a dual afb set up and have toyed with the notion for an upcoming 425 build... i don't have a manifold for the build yet so i'm not gonna rule out going that route. i figured if i did i'd just bite the bullet and buy a pair of new 500cfm e'brocks...
#11
Detonation I haven't had a problem with that I know of. To be honest I wouldn't be able to hear it. Now I run Cam II at roughly 50/50 with 93 and at times just the good stuff.
I went with the duals cause I've had them since '76 and I can finally use them. They look cool and as for performance I can't complain, scary at times. Next build will have a Torker or Victor depending on how I want to use the car.
I went with the duals cause I've had them since '76 and I can finally use them. They look cool and as for performance I can't complain, scary at times. Next build will have a Torker or Victor depending on how I want to use the car.
#12
i figured that you were doing something with the fuel, the highest octane pump gas i have locally is 91 so that is what i run in my '70.
if i go with a single carb on my 425 it'll be a torker. i imagine that is the route i'll end up going, i'm gonna keep an eye open for a dual quad intake but unless i order one from offenhauser i'm not real optomistic about running across one... looking is half the fun anyway.
have fun with 'er, love the lope to the cam!!
if i go with a single carb on my 425 it'll be a torker. i imagine that is the route i'll end up going, i'm gonna keep an eye open for a dual quad intake but unless i order one from offenhauser i'm not real optomistic about running across one... looking is half the fun anyway.
have fun with 'er, love the lope to the cam!!
#13
Fired it up, ran smooth. Needs some fine tuning. 10pm here so had to shut down, don't want to disturb the neighbors. Took alternator apart and gave it a coat of paint. Ready for the spring shows.
#14
I think i want a dual quad for my 455. That just looks bad ***.
Just a question, what's with the spacers under the carbs? is that needed for linkage clearance or?
Are the carbs throttle arms connected 1 to 1?
Just a question, what's with the spacers under the carbs? is that needed for linkage clearance or?
Are the carbs throttle arms connected 1 to 1?
#15
I added the spacers to get the high rise effect, aid in keeping the carbs a little cooler and to have the air cleaner poke thru the hood (fiberglass). I got my steel hood but it bent a little when it flew open at 35 mph which is another story. I think the throttle linkage would clear without the spacers.
The linkage is progressive, A Lokar setup including the throttle and transmission kick down. The second carb kicks in around 2500 - 3000 rpm maybe 1/3 throttle or so. The cam kicks in at 3000 rpm and the car pulls pretty hard.
The carbs I got are a little big. Go with 600 CFM or so maybe.
#17
Just a couple of vids.
http://www.youtube.com/watch?v=SLGziooczCw
http://www.youtube.com/watch?v=c5RGjD6Gcvo
http://www.youtube.com/watch?v=SLGziooczCw
http://www.youtube.com/watch?v=c5RGjD6Gcvo
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