Thursday, March 1, 2007

Cold Weather and the Dreaded Weber

The Pacific NorthWest has been experiencing its last throes of Winter these last few weeks. Ever since Puxatawney Phil didn't see his shadow, it seems like the weather gods have decided to prove him wrong: there will be more winter. Here in the Pacific NorthWest, we've had "wintery mix" which means rain, freezing rain, sleet, hail and snow shifting from one to the other throughout the day. Did I mention gusting wind? Oi. It makes driving a little more exciting, but traffic a real bear.

When the air gets this cold, it takes a long time for Hapy to warm up. When I first bought Hapy, he was missing a number of pieces that helped to keep him warm - making his warmup never complete in winter. I'll go into those part identification and installation adventures another day. Even after finding and installing all those parts, though, the non-stock Weber Progressive 32/36 carburator would not perform well in the cold. If the air temp fell below 50F degrees, he would buck and toss like when I first learned how to drive a clutch. If you're having the same experience, I'd suggest you try this:

First, find a snorkelled air cleaner that fits the top of the Weber 32/36. I bought a "Sprint" air cleaner from Pierce Manifolds for $15. This fits perfectly on top, and bolts down with the filister bolts you use on the chrome air cleaner the Weber came with. This will allow you to control warm and cold air entering the carb.
But where does the warm air come from? Look at the right side of the firewall when looking in through the access hatch (top or rear). Is there a steel elbow that points up that's maybe 2 inches across? No? Is there a square hole with 2 bolt holes on either side of it? Yes? Ok, you're missing 2 key pieces of tin for getting the warm air into your carb. Now, if you have a fuel injection (FI) firewall, you may not have either of these items, so you may have more tin to replace. Honestly, if you have to go that far, you may want to consider returning to FI. Anyway, the pieces are on this diagram, numbers 42 and 43. Number 42 is the elbow on the inside of the firewall and #43 is a longer elbow that bends around the fuel pump (if you have a mechanical fuel pump) and to the firewall. I got these 2 pieces from my man Ken at theBusCo.
Getting these pieces to align without dropping the engine is a challenge, especially if you have a mechanical fuel pump, as the longer elbow needs to fit between the fuel pump and some of the engine tin. You do have a hole in the tin where the long elbow comes down, right? No? Ok, you have newer tin so you can either buy a "new" piece or cut your old one. I cut mine and I now regret it as I have to plug the hole to put FI back on. All of the pieces do fit together, and it can be done by yourself, but its much easier if you can get a friend or a willing child to hold the small elbow in place as you thread the filister bolt through and tighten it down. When its raining, and you're working in your driveway (as I was), you really appreciate hot tea afterwards... and a long shower.
After the tin is in place, and the snorkel is attached, you've finished the hard part. You need a flexible air hose to connect the small elbow near the firewall to the lower part of the snorkel. I got a standard sized one at the local GI Joes. Route the air hose under the long intake runners so its out of the way and any residual heat will warm the runners a little.

To make use of the new equipment, lift the flapper on the snorkel all the way. This will bring just the warmed air up into the carb. In Summer, lower and click-shut the flapper so only cool air enters the carb. This is important as in the Summer using only warm air can overheat your engine. Also, you get better power with cold air entering the carb, so you may want to play with where you set the flapper. You should find that by using the snorkel, you can drive your bus down into the 30F temps before you have the bucking return.

This Winter, especially these last few weeks, I have driven my bus in 35F temps uphill on the interstate. I have had to stay in the right-hand lane, but I've been able to stay on the road. Two years ago, that would not have been possible. If you're having troubles with your Weber and either can't afford to get FI ($250) or don't want the hassle of working on a FI powered engine, you can get the tin, snorkel and the hose for under $50 and a couple hours work. Just try to find a dry place to do the work.

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