Where is the oil fill on my 1949 dodge b1d

[Matthew]

Hey guys, I just bought a 1949 dodge b1d with the 230 i6. This is my first rebuild, as I am 19 years old. I was just wondering where the oil cap might be? I found the oil filter but am struggling to find the cap to fill. Also any advice would be great as I'm new to this world. 

[Reg Evans]

Here it is on a little earlier flathead 6.  The round cap just behind the generator.

 

[Matthew]

Thanks so much. I had a feeling that was it, but I was worried because when I had it running yesterday there was smoke coming out of the top 

[Reg Evans]

Yeah, the smoke is called blow by. Some marvel mystery oil in the crank case and fuel tank might clear that up if the engine has been sitting for a while.

[Matthew]

Thanks so much. I really appreciate the advice. 

[Ash84]

Hey been having same issue with smoke around my cap I been wondering if I should replace it or clean it mine is on a 50 Plymouth. And were to order one can't seem to fine the proper one on the internet.     

[TodFitch]

9 minutes ago, Ash84 said:

Hey been having same issue with smoke around my cap I been wondering if I should replace it or clean it mine is on a 50 Plymouth. And were to order one can't seem to fine the proper one on the internet.     

Bringing up an old thread? Good to do your search but this might also be a topic for a new thread.

 

Anyway, the smoke is blow by getting past your piston rings. If the rings are in good shape there shouldn’t be too much smoke showing but there will likely be a little when the vehicle is stationary regardless.

 

The oil filler cap has two functions. The first is obvious: A place to add oil to the crankcase. The second is a bit less obvious: It is part of the crankcase ventilation system.

 

To reduce the build up of sludge from the water, acids and other stuff in the blow by, clean filtered air is drawn through the crankcase to draw out the blow by. The vacuum for this is provide by the draft tube located at the rear of the engine under the exhaust manifold. This operates via the Venturi principle (basically air moving under the vehicle creates a vacuum in the tube going down into the air flow from the engine). The supply of clean air is through the oil filler cap. That mesh material in the filler cap, when soaked in heavy engine oil, captures any dirt in the air being sucked into the engine.

 

But this system only works when the vehicle is moving. When stationary there is no vacuum on the draft tube so no suction pulling air in through the oil filler cap. Instead, any blow by pressurizes the crankcase and then tries to leave through any available opening. That same oil filler cap and the draft tube are the main openings available so you see smoke coming out of the filler cap and probably also the draft tube.

 

Replacing the cap won’t fix it (i.e. seal the smoke in).

 

If it really bothers you there are at least a couple of things you can do, most authentic would be to overhaul the engine to have a good seal around the rings. Since rings never seal 100% this will only reduce (sometimes greatly) the smoke but not totally eliminate it.

 

The second is to modify the crankcase ventilation system to be a "positive crankcase ventilation" (PCV) type. For the PCV modification you can either get the setup used on these engines when they were used by the military or use some modern bits and pieces and create your own. The modification is basically to remove the draft tube and connect the draft tube opening in the block to the intake manifold with a PCV valve in the line. You may also have to adjust/modify the carburetor to compensate for a change in mixture. A number of forum members have done this modification and you should be able to find how they did it with some more searches.

[Ash84]

20 hours ago, TodFitch said:

Bringing up an old thread? Good to do your search but this might also be a topic for a new thread.

 

Anyway, the smoke is blow by getting past your piston rings. If the rings are in good shape there shouldn’t be too much smoke showing but there will likely be a little when the vehicle is stationary regardless.

 

The oil filler cap has two functions. The first is obvious: A place to add oil to the crankcase. The second is a bit less obvious: It is part of the crankcase ventilation system.

 

To reduce the build up of sludge from the water, acids and other stuff in the blow by, clean filtered air is drawn through the crankcase to draw out the blow by. The vacuum for this is provide by the draft tube located at the rear of the engine under the exhaust manifold. This operates via the Venturi principle (basically air moving under the vehicle creates a vacuum in the tube going down into the air flow from the engine). The supply of clean air is through the oil filler cap. That mesh material in the filler cap, when soaked in heavy engine oil, captures any dirt in the air being sucked into the engine.

 

But this system only works when the vehicle is moving. When stationary there is no vacuum on the draft tube so no suction pulling air in through the oil filler cap. Instead, any blow by pressurizes the crankcase and then tries to leave through any available opening. That same oil filler cap and the draft tube are the main openings available so you see smoke coming out of the filler cap and probably also the draft tube.

 

Replacing the cap won’t fix it (i.e. seal the smoke in).

 

If it really bothers you there are at least a couple of things you can do, most authentic would be to overhaul the engine to have a good seal around the rings. Since rings never seal 100% this will only reduce (sometimes greatly) the smoke but not totally eliminate it.

 

The second is to modify the crankcase ventilation system to be a "positive crankcase ventilation" (PCV) type. For the PCV modification you can either get the setup used on these engines when they were used by the military or use some modern bits and pieces and create your own. The modification is basically to remove the draft tube and connect the draft tube opening in the block to the intake manifold with a PCV valve in the line. You may also have to adjust/modify the carburetor to compensate for a change in mixture. A number of forum members have done this modification and you should be able to find how they did it with some more searches.

Very helpful and a good education in my vehicle it does bother me at all knowing this original engine is operating like normal.

[greg g]

This should lead to the question of how's my compression.  Lack of compression can indicate worn or broken rings. This allows air being compressed by the pistons to pass the rings and bleed into the crankcase.  Much of this is normal wear from use. But it can also be an indicator that your vehicle is wanting a rebuild.  It was common to rebuild these engines somewhere in the neighborhood of 60 to 70k miles.  This due to a lot of factors that we don't face any more.  Think dirt roads and less than efficient air and oil filters.

 

So you might want to break out the compression tester, and the vacuum gauge.  Knowing and interpreting the results will give you a more informed knowledge of what's going on inside your engine.  Stock compression when new was in the 120 psi per cylinder region.  In a worn engine peak compression isn't as important than large variation between cylinders.  Any thing in the high 80s to low 90s would be judged normal and good. Below 70 indicates wear that should be addressed.  Idle vacuum should be 21 inches with a steady needle at 500 rpm idle.

 

 There are lots of websites detailing the why's and wherefore of doing these tests.  Check out the info under the downloads and resources drop downs on this forums home page.