Pressure in the fuel tank, and a timing adjustment

Ever since we bought Vandejo, there has been gas fumes. When we first got her home, we dropped the engine and replaced all fuel lines and vent lines, but the fumes persisted. A couple days ago I finally go around to taking the firewall out so I could make sure all the vent lines were right. On hot days especially, when I stop and open the gas cap, a large amount of pressure releases out of the fuel filler neck, making us think the vent lines are not working right.

First of all, removing and installing the firewall while the engine is in place, is quite the pain. The top of the firewall has a flange that sits in a groove. It’s getting that flange in place, while also ensuring that the front tin around the engine case is in the proper spot. The proper spot is to the rear of the firewall.

Once I got the firewall out, I disconnected the vent lines. There are two stubs coming out of the top of the gas tank. One on the passenger side and one on the driver. I took a piece of extra fuel line I had and connected it to each stub and blew into them to make sure they were free and clear. And they were. Those stubs connect to a rail which leads up into the air intakes on either side of the bus. I blew into each of those rails, and there was a lot more pressure. I am not sure if there should be any pressure at all, or if there should be some. I took the air compressor and blew air into the lines that lead up into the air intakes to make sure it was cleared out as much as possible.

I’ve not smelled any gas since doing this, but I’m not sure that the vent lines were even the cause. I’m wondering if the fumes may not have made it inside the bus via a broken seal between the engine bay and cab. Well, I put all the vent lines back together and replaced the firewall. We’ll see what happens.

Since we are trying to get the bus running it’s best before an upcoming camping trip, I decided I would check the dwell and timing. The dwell was at 58, which is a bit high. I adjusted the point with my .010 feeler gauge and got it to 52. Close enough :) During this, I knocked the vacuum line off the auxiliary air regulator, causing the engine to not idle. It would just die. I was starting to regret doing any work. After all, it was running “ok” before. Quick check in the engine bay and I found the vacuum line and felt much better when the engine idled. A quick adjustment to the timing and we were done for the day. I’m hoping to get to the spark plugs and oil change tomorrow.

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