Botched Edelbrock 1407 rebuild?

[Geff McCarthy]

Thanks!Vacuum about 11 from the small orifice on front of carb. 10deg per the book! Will try both vacuum and check. Too much rain here in PDX today. !
And is the fuel level ok? Can too high affect the fuel/air mix?

 

[Geoff 2]

Too high=rich
Too low=lean.

D. Vizard claims that a 0.100" change in fuel level [ not float level ] is about one jet size.

 

[Geoff 2]

I think you start a new thread, & give a FULL description of the engine/history of the problems etc. Then better able to help you.

 

[Geff McCarthy]

Thanks,will recap in new thread. Today set timing 14 deg, perhaps idle a bit smoother, still backfires and quits. Note steam out rt side only. (no x pipe). Does that mean one bank rich or lean, and corresponding side of carb is mis-set?

 

[furious70]

Do you have a temp gun to see what the side to side temps are doing?

 

[Geff McCarthy]

i do! Will check.

 

[Geoff 2]

If it is steam: suspect a crack or leaking head gasket that is letting coolant into the chamber. Would expect low coolant level in the rad. This scenario also ties in the symptoms.
I doubt that it is steam from condensation [which is normal ] because you would expect it from both exh pipes.

 

[Geff McCarthy]

Thanks again for the idea of measuring the engine temps. As you can see from the data, #1 and #2 are comparable, but the rest of the left exhaust manifold is much cooler than the right, as is the temp on the L downpipe . EGT = exhaust gas temp. OAT = Outside Air temp. I took a video of the backfire every time I opened the throttle from idle, but cannot deduce how to include it. As you can see there is a large difference in exhaust condensation; much less on left. I am not sure how to interpret this. There is also an exhaust gasket leak, but I can't remember which side, and am too deaf to differentiate. Can anyone offer any logic here?

 

[Geff McCarthy]

SummaryThanks to all who have helped me so far!
Car, 63 SF vert, with 78 400 block, Edelbrock Performer 383, Edelbrock 1407 carb, "rv cam" Was running well, then...
Problem: After hard acceleration, loss of power, wich restores in a few sec, but sometimes results in minimal power, just enough to stagger home.
Initial hypothesis seemed to be fuel feed low.
Replaced cap, rotor, wires, plugs. (Has MOPAR electronic pickup.)
Initial carb teardown showed most specs close, but rubber debris obscuring 1/4 of the tiny carb filter.
Replaced fuel filter and most of lines with new, Gates line. Curiiously, now the pressure will not rise above 3, with the regulator turned to max.????
Carb off and on 3x! (I can field-strip an Eddy faster than my M-1 Garand...) Persistent backfire.
I tried one stage richer seats and needles, no change. backfire. Tried different pump holes, no change.
Fuel level in bowls about 1/8" or less above the level in the U shaped baffle.
Tested for vacuum leaks by spraying brake cleen around base. No change in idle. It does idle smoothly.
Temps on both sides: definitely cooler on left, and left exhaust has much less condensation than right.
Grandson with good hearing confirms exhaust gasket leak on left.
Timing 14deg static with vacuum hose off. Advances with rpm, same with hose on. Total about 40.
Fuel gauge now inop. I did jack it up and assure the connector was on, and checked for continuity with some ohms showing.
So...what next? Drop tank down and pull fuel sender unit to check for blockage? Note normal fuel levels and seemingly adequate fuel flow now.
Fix exhasust gas leak? I cannot derive a cause for backfiring from that leak...

 

[Geoff 2]

This is my last post in trying to help you because you just ignore suggestions about what to check. I asked you about low coolant level in post #27, no answer. That would explain a lot. Low coolant level + steam suggests blown head gasket, or crack in head or block. Could also explain backfiring, coolant shorting out spark plugs.
In areas where temps are below freezing, frozen water in the block without anti freeze can crack block/heads.