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Exhaust baffle spring


willits18

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I have a 1950 B2D that I just got running and have driven around the neighborhood. It doesn't seem to have power when under load. I rebuilt the carb, fresh tune up, set the timing, and replaced the brakes.  I also did a chassis overhaul on it replacing the king pins in the front,  repacking the front wheel bearings,  replacing the rear axle grease seals, and  drained the rear end and new grease (90w oil).  All of the wheels turned freely in the driveway.  I did notice that there is a baffle in the exhaust manifold that seems to turn freely. It has a weighted cam on the outside. Isn't there supposed to be a spring hooked up to that to help it to open? I have never worked on this particular truck, but do remember on the 60-70's cars that this  restricted  the exhaust when cold to help warm up the engine faster. If someone has a picture of their similar setup it would help to either let me know that it doesn't need one, or that it does and it is missing. It has a 230 flathead 6 cyl. engine. I bought a new exhaust system from DCM.  It does look small. It is the one that they had listed for that truck. I have not tried to disconnect the exhaust.  All help greatly appreciated! Thanks, Tracy. 

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36 minutes ago, JBNeal said:

Thanks Brian. The coil spring is missing on my manifold. I found one on ebay and ordered it. In the meantime I wired the riser open and it did not help. I am thinking fuel or exhaust system. The exhaust is brand new. I just rebuilt the carb. It is a Stromberg 1 barrel. I put a 6 volt electric pump in it along with a new Stainless steel tank. I will replace the fuel filter with an inline plastic visible filter. It seems to have good pressure. I bench tested the carb and it seemed to spray good. I will post results each step of the way. Thanks again, Tracy.  additional information :cool:

 

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1 hour ago, Reg Evans said:

Have you checked your vacuum advance ?  If it's torn the truck will be very sluggish.

 

I thought the 1 ton trucks didn't have a vacuum advance. But it would certainly affect things if it does, and it's faulty.

 

Also, check your throttle linkage. Be sure that it goes to full throttle when the pedal is pressed all the way down.

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Merle is correct. There is no vacuum advance, and there is no place for piping or tubing  for one. I will check the throttle linkage. I had to do quite a bit of work on it to get it to move. There is not much pedal above the floor. I may try to add some length to the rod that comes through the floor to be sure. I already replaced the stone fuel filter element with a visible plastic one. Thanks Merle and Reg. 

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Those plastic fuel filters aren't designed to be located that close to a heat source...I soaked my stone filter for a week in lacquer thinner, then repeated with fresh lacquer until it was clear after a week...ran with it for years, with an annual lacquer soak to flush it out :cool:

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I've got a 49 B2D-no vacuum adv either.  You may want to check your linkage to make sure that you're getting full throw at the throttle shaft from the pedal.  Several places where there could be loose, bound, bent, or missing pieces.   I'm not familar w the Stromberg for that model, but do you have the arm that attaches to the carb lined up properly on the shaft?   

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The carburetor has a step up jet that takes over after the initial richening of the accelerator pump.  It is vacuum operated to stay closed at idle and cruise both high vacuum states. If it is not getting its signal it will stay open causing an over rich mixture and leading to plug fouling and or misfires.  The vacuum path is from the intake manifold through the body of the carb.  This is provided by a slot in the carb to intake manifold this slot aligns with a hole in the base of the carb allowing high vacuum to pull the needle valve closed when a rich mixture is not needed. Do you recall if the slot was present and properly positioned when you reinstalled you carb?

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How does the engine  sound / smell at idle and under load? Did you check / replace the springs for the mechanical advance at tune up? The stock exhaust DCM sells works perfectly fine as long as there are no obstructions. Lastly, what is your new fuel pump outflow set at?

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I tested the throttle linkage by placing a half concrete block on the pedal and checking the throw-travel. It was almost full throttle. I disconnected the rod from the carb lever and could only move the lever slightly.  I am going to add about 1" to the throttle rod to make sure I get full throttle. As I remember there are no vacuum ports in the intake manifold surface. The gasket just has the 2 bolt holes. That being said the mixture is certainly bot rich. It feels like it is not getting enough gas. When I close the choke all the way it still does not get rich. When I rebuild carbs I bench test them doing a squirt test. This one squirted, but it didn't squirt as much as I would think that it should. I'm just not sure. I was going to add 1" to the accelerator rod and if that doesn't help I was going to go back through the carb. I have never worked on one of these, or any 1 barrel for that matter. I am just not sure what it takes to get enough gas to supply full power.  I did not replace the advance springs. I really have never done that before. They are visible under the cap. I have not seen those on DCM or Roberts. I don't know of any other sites that sell the old Mopar flathead parts. I bought the electronic fuel pump from DCM. I didn't see any adjustment info or even any place on the pump to do so. 

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I replaced the cap, rotor, points, and condenser, along with the plugs and wires. I also put the waterproof wire setup on to better guard the plugs. The distributor felt fine. Smooth bearing or bushing-no lateral movement.  Set timing and rechecked just yesterday. Still fine and no drift. I set points at .20 and plugs at .40.

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I may have found springs at VPW. I would have to look through my records. I would think you would see other signs if it was your mechanical advance. Does the original fuel pump work enough for a test spin to rule out fuel delivery? Does the engine idle and rev smoothly in place? Is your fuel line new and unobstructed?

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The entire fuel system has been replaced. Tank, lines from tank to carb, filters, and new pump. I watched the glass filter bowl fill up with the pump on engine off and it seemed to fill ok. I haven't tried the original pump.  I would have to bypass it and reconnect to the original pump.  I will pressure test the pump. If I remember it should be between 3 1/2-5 psi.  The engine runs great in the driveway. It idles good and revs good until I put it on the street. 

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I have good fuel pressure to the carb-6 PSI.  That is just a bit high but the carb is not leaking and the engine doesn't seem to be running rich at all. I probably need to go back into the carb. I rebuilt it 3 months ago, but have never rebuilt a Stromberg or a 1 barrel. Everything seemed to work ok. I cleaned out all of the ports and the jet.  When I did the squirt test it squirted but I didn't think it squirted like it should. It just seemed a little weak. I have rebuilt many carbs before, but never a Stromberg or a 1 barrel. Anything special I should look for or give special attention to? 

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Have you replaced your Fuel cap by any chance? New caps are non vented. This will cause a vacuum to be drawn on the tank and reducing fuel flow.It can reduce it to the point that the carburetor starves of fuel and the engine dies. If you have bought the new non-vented cap, it can be converted to vented by removing the center piece from the cap. 

Edited by johnsartain
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Does the engine bog under load or die? The fuel flow is strong ( a little high), so probably not locked. The cap could be partially blocked causing some pressure build up (but probably not). If my pump was dialed up that high my truck would run pretty rich, so maybe take another look at the carb. This still feels like a possible distributor issue (coil, condenser, points etc.). Just because they are new doesn't mean they are good. Did you completely tear the carb down and rebuild?

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I did totally tear down the carb. I will just take the cap off and see how it runs. It is not a pressurized system and shouldn't matter. The tune up parts are all new.  I will pull a plug and short it against the block to see how the spark is.  As far as I know there is no other way to test the spark output. Like I said before when I bench tested the carb it squirted, but I felt that it was not what it should be, however I am used to doing 2& 4 barrels and have never done a 1 barrel before. 

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