Thanks for the numbers Brice, I'll take a look around and see if I can find that material. I’m willing to try anything, there is a solution if we look hard enough.
I will be the first one to admit that the Rochester "B" carb is a pain in the ars when it comes to keeping it from leaking. Putting that aside, from what I can see that’s it’s only flaw, although it is, a really BIG one. However it is well documented in this thread in lists, all over in manuals, archives, etc., that this carburetor was used for around 15 years by hundreds of thousands, if not millions of GM vehicles. If this carb had been a problem in its day the dealers complaints and the GSD would have certainly prompted GM to make some major changes or replacements. Not to say that there aren’t any out there, but I have yet to see any service bulletins from GM that refer to the warpage of the castings. They generally all address the adjustments and replacement of the consumables, i.e., accelerator pumps, needle and seat, gaskets, etc.
From my observations so far this year, the problem is not with the circuit design or performance of the carburetor but with the aging process of the Zinc casting over many decades. When you find one that is not warped or one that has been successfully cleaned, rebuilt and adjusted and one that does not suffer from a leaking problem, they are a simple, reliable metering device. They are easy to understand, easy to rebuild and easy to service. If you have a properly gasketed or sealed Rochester “B” its going to perform just fine through out the power range and give you good mileage just as any of the Carter carbs would. I have seen many AD’s this summer that are running the stock carburetors, some have the typical complaints of leakage to varying degrees and some guys very happy with them and no complaints at all. The later must have gotten good castings!
I have five “B”s here and am always on the lookout for more cores or parts to experiment with. After disassembling all of them, I’ve found numerous discrepancy in the way the PO’s had rebuilt/butchered/jerry rigged/altered/improperly reassembled them, in an attempt to get them to run right. Each of them really only has one major problem that could not be fixed by using the proper parts and rebuilding technique, and that is Aging/Zinc Creep/Warpage.
If fresh castings were being made new today you would have a fine little carburetor, at least for 10 or 20 years until the castings began to age and warp. Some day as fuel metering devices become more and more scarce someone might just invest in a set of molds to do just that, re-cast a bowl and air horn. But when that time comes I would hope they would give us six or eight #10-32 hold down screw around the perimeter instead of four and maybe a few round the Venturi.
I’m getting some encouragement from several other sources as to the possibility of successfully rebuilding the “B”, so I’m not giving up yet! New ideas are popping up every few days.
Denny Graham
Sandwich, IL
