Thanks Doc Hall; yup mine was a little sticky but actually popped out with no issues. I have scrubbed r' out with a bronze bore brush.
Accelerator pump is squirting well. The "umbrella" is still soft.
Believe the issue (as with many running issues) wasn't the ole' Rochester at all but simply this severe intake (vacuum) leak. I'll be able to try it out later this afternoon and if she leaks again I'll have to turn some adapter rings on the lathe, it has the small port intake and large port heads so it's kind of floating around.
As is the usual case with this site you are receiving quality information. I'm Known as the Rochester B, BC & BV Nazi in my local area. Something that many miss on the rebuild is the power piston. once you take the air horn (top of carb., four screws), check the power piston, this is the tube that looks like a ball point brass refill. Very carefully pull it out, if is hard to move soak well wth Krol oil or Blaster etc. NEVER WD-40 (it will crystallize under heat). Twist very gently and pull base with needle nose pliers. You do not want to break it, it cannot be ordered. there is a small spring under it so don't loose it either. I always polish the chamber and stem with a small round gun brush. This has to move up and down, if it is not free it can cause all kinds of problems. Also be sure the the accelerator pump is not sticking and is clean, gently brush out the well and put the right number of balls in the well pending carb casting. Doc
These are very good points. Also make sure the piston goes in the hole & knocks the ball off its seat. Often it is bent or the holder is not aligned good & the piston rod does not go in the hole. George
I got it running and it actually ran really well with the new intake gasket, purred like a kitten. Doesn't even seem to smoke. Unfortunately, as it got hot the intake started leaking again (for the reasons I learned in this thread - 49 intake, small ports on a 57 head with big ports, and only the small rings just floating around).
So I'll be machining new adapter rings for this mismatched unit and ordering those better gaskets.
I'd call this "solved" at least. I'm glad to know the challenge and deal with it.
On the material side, I was just going to use mild steel pipe. I'll second DocHall's question, what did you use?
The factory rings develop surface rust pretty quick in the elements so I presume they are just high carbon steel, needed to make them act like springs to take up the slack in tolerances from engine to engine. I could pick up some stainless but it's pricey. Hoping to start turning these this afternoon.
I'll start a new thread on that for discussion after I get them done.
Last edited by NorthCoast3800; Wed Aug 26 2020 04:56 PM.