6770BigBlock
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Does anyone know the proper method for tuning Carter AFB's on the long Cross Rams?
Thanks
Thanks
Tuning Carter AFB's on Cross Rams
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miller
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I can't from experience. Should be able to, since at one time, I had a set...paid a whopping $25 for them, thinking on using them on my 69 RR I had then. Baby brother did me a big favor, and scrapped 'em, while I was on a trip!
Do you have the motor running? Or is this first time start? Considering all the variations involved, such as cam, jet sizes, and such, probably plan on good plug reading. Being a two piece intake, each feeding the opposite bank, the carbs being fairly balanced will be the best start. Maybe just good adjusting will do it.
If it is running...what's it doing?
Do you have the motor running? Or is this first time start? Considering all the variations involved, such as cam, jet sizes, and such, probably plan on good plug reading. Being a two piece intake, each feeding the opposite bank, the carbs being fairly balanced will be the best start. Maybe just good adjusting will do it.
If it is running...what's it doing?
6770BigBlock
New Member
Yep it's running. Just seems like I am losing power at the top end with it. I rebuilt the carbs which has helped some. They have been on the car since 71 so long overdue. I just wasnt sure if there was a certain process with this setup or just try and match them up and go from there.
Ski 61701
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What is your current jetting on the carbs? Is your fuel pump pushrod in decent shape lengthwise? Make sure your carb base gaskets are good, I only use them once and throw them away, you might have a tiny air leak.
You can buy a solex carb sync hat and get a carb hat and glue it on the hat. Pop off your carb linkage after motor has warmed up. Put the hat on and look at where the check ball is and go to other carb. Compare levels and use idle screw to get check ball equal to other carb reading. Just make sure your base timing is advanced enough so you dont uncover idle transfer slots. Also make sure your metering rods are in the down position at idle, you dont want them fluttering up n down.
I monkeyed with mine and once I got them dialed in whole different motor from idle to full power.
You can buy a solex carb sync hat and get a carb hat and glue it on the hat. Pop off your carb linkage after motor has warmed up. Put the hat on and look at where the check ball is and go to other carb. Compare levels and use idle screw to get check ball equal to other carb reading. Just make sure your base timing is advanced enough so you dont uncover idle transfer slots. Also make sure your metering rods are in the down position at idle, you dont want them fluttering up n down.
I monkeyed with mine and once I got them dialed in whole different motor from idle to full power.
miller
Well-Known Member
Ski 61701 makes some great suggestions. With those intakes, I suspect the related parts and pieces need to be in top notch shape, for it to perform right.
Losing power at top end? I'd also take a look at the ignition, distributor, just to be sure your getting the needed advance, or even getting into point float.
I think I remember seeing service data (performance) on those manifolds/carbs. Might be worth a look at any sites that supply those service publications...maybe 60-63.
But, past that, yeah, matching the carbs, and alot of keeping track what the plugs tell, is what I'd do.
Mark B
Well-Known Member
The info on the long rams I have read shows a drop off in power at high rpm due to restrictions. The short ram is actually the same manifold but the divider between the two runners is shortened to provide better top end. You could have bungs installed in the exhaust and use a wide band to check your carb settings.
miller
Well-Known Member
For what it's worth...
Texas panhandle, mid 60s, a local lawman used a Chrysler 300, with those intakes, for chasing bootleggers. Complained to his mechanic, all the time, 'cause it would start cutting out, around 150mph!
Doesn't mean it not tuneable. Part is nature of the beast. Limits apply.
Texas panhandle, mid 60s, a local lawman used a Chrysler 300, with those intakes, for chasing bootleggers. Complained to his mechanic, all the time, 'cause it would start cutting out, around 150mph!
Doesn't mean it not tuneable. Part is nature of the beast. Limits apply.
miller
Well-Known Member
Might nose around in here...http://www.hamtramck-historical.com/index.shtml
Ski 61701
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Yes Miller has very valid points regarding tuning, thanks for the assist
Remember these manifolds are more torque oriented because of their length. I want to say around 3,000 rpm. So if you are trying for 5,500 and up it might be pushing things a tad. This is where cam selection really comes into play here, if its narrow intake centerline it could potentially limit things before they are theoretically done. These manifolds like a wider int cl, 109-113 int cl, to allow sonic pulses to build up in those long runners, as they were designed to do.
For checking vacuum leaks, I use an unlit propane torch and go around carb bases and center pipe rubber hose connectors. Vary your rpm when checking rubber hose connectors vaccum can do weird things with rubber hose.
Not sure if you are running oem exhaust manifolds or headers. Some people make the blockoff plates that go under the carbs originally they connected to exhaust manifolds, and the corrosive nature of exhaust gases might make pin holes. If someone made block off plates n used wrong gasket material, could have slight prob there n they might leak a little if not sealed correctly.
Also , the metal tubes themselves over the years can develop pinhole leaks, so run propane around everything just to absolutely rule out a leak]. I like propane, its less messy than carb spray, and cheaper too.
Like Miller said check ignition really good is extremely important with cross ram engines
Remember these manifolds are more torque oriented because of their length. I want to say around 3,000 rpm. So if you are trying for 5,500 and up it might be pushing things a tad. This is where cam selection really comes into play here, if its narrow intake centerline it could potentially limit things before they are theoretically done. These manifolds like a wider int cl, 109-113 int cl, to allow sonic pulses to build up in those long runners, as they were designed to do.
For checking vacuum leaks, I use an unlit propane torch and go around carb bases and center pipe rubber hose connectors. Vary your rpm when checking rubber hose connectors vaccum can do weird things with rubber hose.
Not sure if you are running oem exhaust manifolds or headers. Some people make the blockoff plates that go under the carbs originally they connected to exhaust manifolds, and the corrosive nature of exhaust gases might make pin holes. If someone made block off plates n used wrong gasket material, could have slight prob there n they might leak a little if not sealed correctly.
Also , the metal tubes themselves over the years can develop pinhole leaks, so run propane around everything just to absolutely rule out a leak]. I like propane, its less messy than carb spray, and cheaper too.
Like Miller said check ignition really good is extremely important with cross ram engines
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