The Stovebolt Site Forums The Shop Area Engine Shop Rochester "B" parts source ?

I have rebuilt the Rochester "B" 1 BBL a couple of times with no great improvement. Plugs are still sooty and there is a bit of dark smoke from the tailpipes.
(The engine has less than 300 hours since rebuild).
I gotta believe that the needle and jets are simply worn out after 40 odd years.
Can anyone suggest a NOS parts source for the carb internals?
Thanks Mike

Langdon's used to have a few jets. I don't know if carbking would have them. I think they steered clear of Rochesters to the best of their ability. If you look at the tech tips section of inliners.org under multiple Rochesters, there is a very good article that gives a phone number for a "Grose-Jet needle and seat" that is a real trick part.

Mike, it sounds like the base gasket may be blocking the power valve port. Most of the gasket sets have the wrong gasket for the earlier carbs. If the port/ hole is blocked it will run rich, also good for about 4 mpg. You can notch the gasket to expose the port to vacuum.

Dave, you were exactly right!
The carb base gasket from the last kit had four cutouts from the mid line to the center. None of the cuts lined up with the power valve port. The power valve was blocked and dumping fuel at all throttle positions.
I made a new gasket with a vaccuum passage to the bore and hope that will solve the smoke and sooty plugs.
Thanks for shareing that bit of wisdom.
Mike

There are often other issues with modern kits for these carburetors to include incorrect accelerator pump and wrong size orifice in the fuel valve. This is one instance where your local parts house is not the best place to acquire something.

Greg_H - one comment about the valve you mentioned. A few years ago we bought the remaining inventory of a defunct carburetor rebuilder that had used these valves. I don't remember how many cartons of these things we acquired, but there were several thousand valves. As with any product that we have not previously used, we test thoroughly prior to use. After our tests, ALL of these were placed in our "scrap brass" barrel, and melted for recycling.

Jon.

Point taken. I bought a pair and they seem OK in the sense that the rubber tip of the original needle would stick if it sat awhile without starting. This design was as you mentioned a brass housing with a series of check ball trapped inside. In the late 70s there was a Parker needle and seat that I really liked. It was a flat faced brass needle and seat set that resolved many issues with the Bakelite bodied Carter carbs on Mopar Lean Burn engines.

Unfortunately, Parker Brothers did not survive Clintonomics. It was an excellent design!

Jon.

Hey guys, the gasket that didn't have the power valve hole..... what brand are they? Did they come from Chevy Duty? I'm just wondering, as I have recently rebuilt a Rochester B, but have not fired the engine, and just wanting to know if I should "double-check" to see if the gasket is right.

I have tried several brands and have not seen the correct gasket for years. Almost every 235 that comes into my shop has the wrong gasket.

The later design model B carb has two holes on the base gasket surface, the second is drilled at an angle over into the original port. The gasket that comes in the kits works on this type base.

The referenced link shows an "almost correct" gasket (what should be in the kit), an incorrect gasket, and an aftermarket "fits all" that may be used.

235 mounting gaskets

The original gasket was affixed to a 1/2 inch heat insulator (VERY expensive to reproduce). The
"almost correct" (it is correct except for thickness) gasket should be used WITH the original heat insulator (the insulator sits on the manifold, with the gasket between the insulator and the carburetor).

Jon.

A Quick follow up.
I road tested the truck after installing a new (hand made) base gasket that had the hole for the power jet vaccuum.
It ran perfectly! No hint of dark smoke. The best idle ever and the plugs are now spotless.

Mike

That's what I'm talkin' 'bout!

It does make a difference having the correct parts.

Jon.

I had the same problem just a few weeks ago with my 1959 Rochester B carb. The shop replaced the base gasket. But, I have know idea if it is correct now or not. I haven't driven the truck since they did the work as it went straight over to the paint shop again.

My question is, Jon, which one of the gaskets in the link you posted is the "almost correct" gasket?

I am now going to check to see if the power valve port is blocked. Now for the really novice question - Where on the base of the carb will the power valve port be? Front or rear and driver/fender or passenger/valve cover side of the carb?

Thanks!