[C1] Dual four Help
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Joined: Aug 2017
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Dual four Help
I have a 1957 245hp dual four. The 283 is rebuilt and completely stock. I removed the intake manifold to replace the gaskets , my plugs where oil fouled and I suspected it was drawing oil into the intake runners.
the intake gaskets definitely needed changed.
I get it back together and now it is running very lean on the main jets. It does idle smoothly but at about 1500 rpm it has a rough idle and the engine is running hot. We pulled the plugs and they indicate lean.
I tried an experiment, I left the throttle closed on the rear carb and open the front carburetor. It still is leaning out.
the WCFB’s are correct ‘57 units.
metering rods are 1350
main jets .935
secondary jets .053
any ideas on what could be creating this lean condition?
the intake gaskets definitely needed changed.
I get it back together and now it is running very lean on the main jets. It does idle smoothly but at about 1500 rpm it has a rough idle and the engine is running hot. We pulled the plugs and they indicate lean.
I tried an experiment, I left the throttle closed on the rear carb and open the front carburetor. It still is leaning out.
the WCFB’s are correct ‘57 units.
metering rods are 1350
main jets .935
secondary jets .053
any ideas on what could be creating this lean condition?
Le Mans Master
Joined: Sep 2008
Posts: 5,662
Likes: 2,344
From: Lake Minnetonka, Mn
2018 C1 of Year Finalist
Just a question or two. How are you assessing the lean condition? Do you have a narrow or wide-band A/F analyzer?
Show us a picture of the "lean" spark plug. Retrace your steps on the teardown and reassembly. At 1,500 rpms you are probably no longer operating on the idle circuit.
Your jetting (primary and secondary) is on the money.
You had to pull the distributor when you replaced the gaskets. Did you reestablish the correct timing on the engine?
Show us a picture of the "lean" spark plug. Retrace your steps on the teardown and reassembly. At 1,500 rpms you are probably no longer operating on the idle circuit.
Your jetting (primary and secondary) is on the money.
You had to pull the distributor when you replaced the gaskets. Did you reestablish the correct timing on the engine?
Last edited by Dan Hampton; Aug 31, 2022 at 07:17 PM.
Melting Slicks
Joined: Sep 2005
Posts: 2,713
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From: Warminster PA
