awasson
Well-known member
Prompted by a recent discussion about the Ford 200, carbs, distributors and exhausts, I thought I’d create a discussion thread specifically about the Weber 38/38 to document what has worked and what hasn’t to add some knowledge. Hopefully we can add some good info others can refer to. Please add your experiences with the Weber 38/38.
Personally, I think the 38/38 is a fairly simple carb to set up on a relatively mild or stock engine but they do require fuel pressure regulation of about 3 lbs, the floats must be set right and in my experience, you need to keep the distributor timing in mind when it comes off idle onto the main circuit.
My car came with an uninstalled Clifford Performance, Redline 38/38 kit so when I rebuilt the engine, I installed the new carb (on the unmodified intake log using the Redline/Clifford adapter) along with an EBay header and single 2-1/2” exhaust to a free flow muffler. According to the documentation, the Weber Redline carb is set up for the Ford 200 and is a bolt and go kit. In my experience it was pretty much bolt on and go. Initially, it fired up and idled without any real adjustments, I only had to adjust the idle speed screw. My engine had zero miles on it, bored 60 over a little under 9:1 compression ratio with a small log head, a Clay Smith H-6474-0-B camshaft and an HEI distributor.
After the initial startup and shake down, I thought it was running rich at idle and cold start so did some reading and followed the setup described at Redline Weber: http://www.redlineweber.com/html/Tech/38_dgas_tunning.htm
Following the setup, I changed the stock #55 idle jets to #60’s and adjusted the mixture to compensate. The following are some notes I took during my setup:
Things I’ve Noted:
1) Plenty of people have installed these carbs successfully but you must follow the base setup and don’t be tempted to try to adjust the idle speed screw until you have the lean best idle.
2) The vacuum port on the carb is “ported” vacuum. At idle there is no vacuum but when you open the throttle and it transitions to the main jet circuit, you get the vacuum. This is a good way to determine whether you’ve added too much idle speed via the idle speed screw; if you’re pulling vacuum on the port, you’re no longer on the idle circuit.
3) Getting the idle jets and idle mixture right improves the whole of the air/fuel system. My guess is that the idle circuit is always active and is additive to the air/fuel situation.
4) My engine seems to want a lot of initial timing and knowing that helped me understand what was a function of the carburetor and what was a function of the distributor. More timing, more fuel.
5) I don’t know how much of a difference it makes but I trimmed the intake gaskets that fit between the carb, the adapter pieces and the log to remove overhanging gasket material. It’s a bit like port matching an intake manifold gasket on a non-log head. I expect it makes some difference.
I haven’t looked at what the air corrector jets and main jets are in mine. They are whatever was installed by Clifford/Redline or Weber when the carb was manufactured. I’ll put an AFR gauge on mine in the Spring and look into dialing the carb in for the whole range from idle to WOT. In the meantime, it would be interesting how others have set up their Weber 38/38 carbs, main jets, air corrector jets, etc. If you’ve got a 38/38 Weber on your Ford 200, I’m looking forward to hearing about it.
Andrew
Personally, I think the 38/38 is a fairly simple carb to set up on a relatively mild or stock engine but they do require fuel pressure regulation of about 3 lbs, the floats must be set right and in my experience, you need to keep the distributor timing in mind when it comes off idle onto the main circuit.
My car came with an uninstalled Clifford Performance, Redline 38/38 kit so when I rebuilt the engine, I installed the new carb (on the unmodified intake log using the Redline/Clifford adapter) along with an EBay header and single 2-1/2” exhaust to a free flow muffler. According to the documentation, the Weber Redline carb is set up for the Ford 200 and is a bolt and go kit. In my experience it was pretty much bolt on and go. Initially, it fired up and idled without any real adjustments, I only had to adjust the idle speed screw. My engine had zero miles on it, bored 60 over a little under 9:1 compression ratio with a small log head, a Clay Smith H-6474-0-B camshaft and an HEI distributor.
After the initial startup and shake down, I thought it was running rich at idle and cold start so did some reading and followed the setup described at Redline Weber: http://www.redlineweber.com/html/Tech/38_dgas_tunning.htm
Following the setup, I changed the stock #55 idle jets to #60’s and adjusted the mixture to compensate. The following are some notes I took during my setup:
- #55 Idle Jets: Idles not bad with mixture screws 5/8 of a turn out but will not rev smoothly; kind of fights itself. Could be more timing required by my cam? Need to investigate further with an AFR gauge.
- #60’s Idle Jets: Set idle mixture to 7/8 of a turn and initial timing to about +16° to +20° advanced. It’s best low idle is at about 800RPM. This works well and seems about the best I’ve achieved to date. Vacuum advance is disconnected and it gets +14° mechanical advance which starts to come on shortly after the carb comes off idle. I’d like to get the vacuum advance into the mix so I’ve still got some work to do.
Things I’ve Noted:
1) Plenty of people have installed these carbs successfully but you must follow the base setup and don’t be tempted to try to adjust the idle speed screw until you have the lean best idle.
2) The vacuum port on the carb is “ported” vacuum. At idle there is no vacuum but when you open the throttle and it transitions to the main jet circuit, you get the vacuum. This is a good way to determine whether you’ve added too much idle speed via the idle speed screw; if you’re pulling vacuum on the port, you’re no longer on the idle circuit.
3) Getting the idle jets and idle mixture right improves the whole of the air/fuel system. My guess is that the idle circuit is always active and is additive to the air/fuel situation.
4) My engine seems to want a lot of initial timing and knowing that helped me understand what was a function of the carburetor and what was a function of the distributor. More timing, more fuel.
5) I don’t know how much of a difference it makes but I trimmed the intake gaskets that fit between the carb, the adapter pieces and the log to remove overhanging gasket material. It’s a bit like port matching an intake manifold gasket on a non-log head. I expect it makes some difference.
I haven’t looked at what the air corrector jets and main jets are in mine. They are whatever was installed by Clifford/Redline or Weber when the carb was manufactured. I’ll put an AFR gauge on mine in the Spring and look into dialing the carb in for the whole range from idle to WOT. In the meantime, it would be interesting how others have set up their Weber 38/38 carbs, main jets, air corrector jets, etc. If you’ve got a 38/38 Weber on your Ford 200, I’m looking forward to hearing about it.
Andrew
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