W-1 Carburetor Questions Icing/Pulsing

I just completed installing a rebuilt 216 with Fenton headers and N.O.S. W-1 carburetor in my ’48 Delivery Sedan. It appears to run nicely (to me) but apparently there is a couple of bugs:

One, I’m getting ice at a gasket seam? Ice... Sheesh?

Second, a guy who claims he has been a mechanic for 35+ years put his hand on the exhaust and said the flow should be steady, and not pulsing like it is? He claims it to be a carburetor problem?

Anyone know of these things?

Thanks!

 

are you running a single exhaust or true dual exhaust.
Is your muffler(s) straight thru ?

 

re:ice - there's lots of cooling potential from gasoline evaporation and air expansion after the venturi. When the relative humidity is high and ambient air is under 50 or so carb icing can occur. The usual solution is warming stuff up. Some aircraft have heated fuel tanks. Some have heat exchangers just to allow carb heating (intake air warmiing) when needed
Carbureted and even fuel injected cars have thermostatic flaps in the intake to warm up the intake air. Engines have heat risers to warm the floor of the intake manifold for better cold weather fuel vapirization even when icing is not an issue

 

Its your headers, the stovebolt chevy, like most six's of the era has a heat riser in the exhaust manifold to warm the intake. Short of going back to stock I don't believe their is a fix for it, unless there is an intake manifold that has a coolant passage in it.

 

There is a fix, although it may not be as "eye-appealing" as one might like on a "rod".

Icing is very common on many inline engines when conditions are "right". Take a look at how Toyota and Datsun solved the issues on their inline fours in the 1970's. A "heat stove" is fabricated from sheet metal, placed on the exhaust (in this case the headers) and an air tube is connected from the heat stove to the air cleaner. Toyota and Datsun had a mechanical valve to allow switching to non-heated air in the summer.

Before doing this, you might try checking the mixture with an A/F meter. Since converting gasoline from a liquid to a gaseous state requires external heat, the richer the mixture, the more heat is required, and the more problems one has with icing. Check to see if you are too rich.

Jon.

 

Yes, I have dual exhausts with regular mufflers on each. It is quiet, but they left a little rrroooom.... (Sounds nice!)

When I had it running, on the engine stand, I had the single exhaust with heat-riser, and true I don’t recall seeing any ice.

Perhaps it is not a gasket leak, and everything is normal as far as getting ice is concerned? The "Fix" sounds interesting carbking/timberlake! I wonder if warming the fuel-line, somewhere where it won't be seen, would help? Still, I will have to get one of those A/F meters. I'm still technically a newbie, and I missed that one.

I would love to hear more about the pulsing exhaust issue. Being a N.O.S. carb (supposedly) I’m hoping I don’t have to send it off to be rebuilt? (BTW I'm getting great vacuum at over 22.)

Thanks!

 

I think your icing question has been answered, and I wouldn't sweat the exhaust pulsing. Unless you have headers with identical tube lengths, the exhaust pulses are not going to be coming down the pipe evenly. It's much more noticeable at idle. I've got a 37 Buick with the original engine and single exhaust. When it idles the engine is absolutely vibration free, you can set a nickel on edge on the top of the rocker cover and it doesn't fall over. I am 99.5% sure that the ignition and carburation is dead on, and the engine doesn't miss. But when I go listen to the eight cylinders all coming out of that one pipe it sounds erratic as hell, as the exhaust pulses coming out of the pipe are not evenly spaced. A 34 inch long exhaust manifold will do that, with the center cylinders dumping directly into the outlet, and the end cylinder's exhaust having to travel through 14 inches of manifold before reaching the same point is going to cause some funny sound.

What kind of dual exhaust do you have? Split manifold? Headers?

 

Ebbsspeed We must have passed each other on the post: I have dual exhausts (Fenton headers with pipes not connected to each other with matched regular-baffled-mufflers on each.)

This one too runs at idle smooth as glass! I actually filled a cup-of-water to the very brim, and put it on the valve cover to show-off to a friend how smooth it is. Not a drop spilled! However, when cold, it is only slightly rough, probably the heat riser issue?

I will say the each exhaust pipe is of different lenghts. About two feet longer on the pipe that feeds under the oil-pan. (Cylinders #1,2,3 side) So, one pipe is about ~24" or so longer. (I did wonder about that myself.)

Thanks!