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| carter bbd cold starting issues 65 Valiant https://slantsix.org/forum/viewtopic.php?t=16165 |
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| Author: | bossanova6 [ Mon Feb 13, 2006 5:08 pm ] |
| Post subject: | carter bbd cold starting issues 65 Valiant |
Hello All. Ever since I converted over to the super six setup the engine is a mother to start. The choke plate is adjusted to fully closed when cold.The thermastic spring ( the choke spring is installed and yes it's from a two barrel manifold) is fully operational and works properly(opens the choke plate fully when warm).The vaccum pot is working properly as well. The carburator seems to flood out as your cranking the engine cold.The only way to get it to start when cold is, to hold the choke plate open manually as well as the throttle plate wide open, and keep cranking until it eventually blows all the raw fuel out.The carb does not leak any fuel from the jets.Once the engine finally fires up.It runs great.One crank after it's been started and it fires right up. When I first did the conversion the engine would fire after 7-8 cranks.Now it practically will wear the battery down before it fires.It also backfires through the carb when its initially cranking as well when cold. The timing is set to 10 degrees btc It has electronic ignition Once it finally starts it runs great without any other issues Thanks for help in advance |
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| Author: | SlantSixDan [ Mon Feb 13, 2006 6:19 pm ] |
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This sounds a lot like a choke pull off ("vacuum pot") adjustment issue. They can work fine and still not be adjusted properly; have you checked the adjustment? If so, how? (For that matter, how did you check the choke pull-off for proper function?) What is your BBD from (model, engine, year)? How is the choke heater hooked up, if it is hooked up at all? How is your fuel line routed between the pump and carb? |
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| Author: | Reed [ Mon Feb 13, 2006 6:52 pm ] |
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Ditto on what Dan said. As soon as the engine starts to run the choke should be pulled open roughly 1/8 of an inch by the choke vacuum diaphragm. |
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| Author: | bossanova6 [ Mon Feb 13, 2006 7:01 pm ] |
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Hi Dan, I checked the choke pulloff vaccum pot visually.Once the engine fires it pulls the choke plate all the way open.With the engine cold and off the choke plate is all the way closed If believe the bbd came off a 71-73 318.There is no tag on it. The choke heater is hooked up and fuctions properly.The choke plate returns fully closed when engine is cold, and remains open when engine is warm.The choke heater is from a late 70's two barrell slant six. The fuel line is routed traditionally from the front over the exhaust manifold. Please remember that the car is getting too much fuel when it's cold. |
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| Author: | SlantSixDan [ Mon Feb 13, 2006 7:11 pm ] |
| Post subject: | |
Quote: I checked the choke pulloff vaccum pot visually.Once the engine fires it pulls the choke plate all the way open.
That is not proper operation of the choke pulloff, which should pull the choke plate open only partially—and by a very specific amount. Further, even a ruptured choke pulloff diaphragm can carry on "working" but calibration will be thrown way off. Best to do this adjustment by the book. I'll find a workable spec for you from some of my FSMs tomorrow at the office.Quote: With the engine cold and off the choke plate is all the way closed
That's a good start, but it's critical not only that the choke plate close completely, but also that it's under the correct amount of tension from the choke thermostat.Quote: I believe the bbd came off a 71-73 318.
OK, that's helpful info. What modifications did you do to the choke lever or choke thermostat pushrod to make the (different) V8 choke lever work with the slant-6 choke thermostat arrangement? Quote: The choke heater is hooked up
Again: How is it hooked up? What've you got it hooked to?Quote: The fuel line is routed traditionally from the front over the exhaust manifold.
Probably not a direct cause of your problem, but this routing can and does cause bîtchy cold starts. When you get round to it, do the fuel line mod.Quote: Please remember that the car is getting too much fuel when it's cold.
Understood. You please remember that cold-start problems can be very intricate and can produce contradictory symptoms that can really throw you off the trail.
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| Author: | bossanova6 [ Mon Feb 13, 2006 7:18 pm ] |
| Post subject: | |
I have the choke heater rod hooked to a tiny link(much like a link in a chain) The choke spring rod is attatched to one end of the link via the proper linkage retainer. The other end of the link is attatched to the choke plate on the carb via a tiny screw.I did this to get the right angle so that the choke plate would open and close properly |
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| Author: | SlantSixDan [ Mon Feb 13, 2006 7:44 pm ] |
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OK...how 'bout the other questions? The choke heater is not the same as the choke thermostat or the choke pushrod. Choke thermostat: A coiled, bimetallic spring in a housing bolted to the exhaust manifold. Choke pushrod: A link rod that runs from the choke thermostat to the carburetor's choke lever. Choke heater: An electric heating element that provides regulated heat to the choke thermostat, in addition to the heat provided by the exhaust manifold |
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| Author: | bossanova6 [ Mon Feb 13, 2006 8:12 pm ] |
| Post subject: | |
I have the choke thermostat rod hooked to a tiny link(much like a link in a chain) The choke thermostat rod is attatched to one end of the link via the proper linkage retainer. The other end of the link is attatched to the choke plate on the carb via a tiny screw.I did this to get the right angle so that the choke plate would open and close properly.I don't have the choke heater hooked up.I've been using the manifold heat alone to open the choke |
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| Author: | SlantSixDan [ Mon Feb 13, 2006 8:23 pm ] |
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Quote: I've been using the manifold heat alone to open the choke
OK, that doesn't work too well with the 2bbl slant-6 choke thermostats, which are specifically designed to work with manifold and electric heat. They are also not adjustable. You would very likely be happier with the full electric choke kit, which is fully adjustable, brand new, and makes it very easy to custom-fab whatever special choke pushrod you may need to reach your BBD carb.
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| Author: | sandy in BC [ Mon Feb 13, 2006 8:24 pm ] |
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On my BBD having the electric heater disconnected makes the car vitually undriveable below freezing. I have the same carb (V8) and the same choke linkage adaptation. |
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| Author: | bossanova6 [ Mon Feb 13, 2006 8:34 pm ] |
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I appreciate your input.But how does not having the electric portion of the choke effect the initial cranking and starting of the engine.Initially everything is mechanically controlled.The electric assist helps the choke warm up faster.My problem is the initial startup and too much fuel causing the engine to flood so it won't start. |
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| Author: | SlantSixDan [ Mon Feb 13, 2006 8:50 pm ] |
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Quote: But how does not having the electric portion of the choke effect the initial cranking and starting
Probably doesn't—but choke thermostat tension does, and that you cannot adjust in the factory-type unit.
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| Author: | SlantSixDan [ Mon Feb 13, 2006 8:52 pm ] |
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Quote: On my BBD having the electric heater disconnected makes the car vitually undriveable below freezing.
On my '65 w/BBD, if I left the choke heater disconnected, the choke would never come off. I didn't have that carburetor on it long enough for the improper hookup I used to bother me (much): I hooked it directly to ignition-switched +12v. Had to be quick about starting the engine once I'd turned the key to "on", otherwise the choke would heat up and come off prematurely.I should neither have hacked nor sold that car. |
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