Don’t fact check me, but I’m pretty sure Ken Miles felt the Alpine was over-carbureted. But those two Zenith downdrafts do look pretty cute on the 1.6 liter four cylinder.
Spark, fuel and air ratios need to be dialed in just right to get the most performance. These carbs drop a lot of fuel in this engine. So much that you will find fuel pooling in the intake manifold. The Rootes Group engineers designed a way to eliminate that pooled fuel when the engine stops. The part is a manifold drain.
The way it works is via manifold vacuum and a check valve with a ball bearing.
When I took off my carbs for a cleaning I found the pooled fuel and started researching the manifold drain. Of course mine was long gone and here’s why. The drain drops fuel right onto the exhaust manifold. I’m thinking that’s a fire hazard, but I decided to make my own drain anyway.
After a quick trip to my favorite brass fitting store. Really, I have a store. Great guy and willing to sort things out with you. I had the parts I needed. I happened to have a ball bearing sitting around too.
The way it works is the vacuum when the engine is running will pull the ball bearing up to seal the intake. When the engine stops, gravity pulls it down. But I’m not sure if the manifold pressure is actually strong enough to seal this.
I put two notches on the bottom for fuel to drain past the ball bearing while it is down.
I tried it but really don’t like the fact that fuel drops on my headers and then on the garage floor. I’m going to continue thinking of a better method. I picture Ken Miles would tell me to go to a single carb setup. Maybe that’s in my future. But these carbs will go on a shelf if I take them off so I can go back to the original setup.
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