TylerW
Well-Known Member
Hey guys:
I recently converted my '73 slant-six Valiant from it's original and leaking Holley 1920 to a 1945.
I know everyone has their own opinion of each carb, but I'm 100 percent glad I did it. The 1945 runs better all the way around and eliminates what I consider design deficits that the 1920 has, primarily potential for leaks, parts availability and a better accelerator design.
The carb I used came from a 1984 Dodge van, no Lean burn. I had to drill and tap the carb for an idle screw since the van used an idle stop solenoid. I also have a '75 1945 and I attempted to hybridize the positive return base off the earlier carb with the body of the later carb, but there are simply too many differences in the way the accelerator pump works between the two.
I also used the 1945's electric choke, which fit right on, and best of all it's over-the-valve cover metal fuel line which repositions the fuel filter down alongside the block on the passenger side.
Here(finally) is the only issue I have:
After sitting 2 or 3 days, the fuel is obviously siphoning back out of the carb. It takes about 2 or 3 5-second cranks before the engine catches and runs, COLD. Hot there is no problem.
It's not flooding into the engine because I checked and the carb throat is dry. It has a brass float which is adjusted properly. The choke is also working properly.
The 1920 would do this occasionally, but it had to sit a couple weeks first. I am speculating if possible my fuel line arrangement at the pump is contributing to, if not causing this issue. I'm pretty sure the van had a short metal segment which exited the pump, curved downward and back up in a 180-degree loop, then entered the fuel filter which was of course mounted with rubber line segments. I think I've seen that on V8 cars also.
I'm interested to hear if anyone has made a connection between loops in the line and drain back problems.
Also, to recap, this has NOTHING to do with hot engine operation. It is strictly a cold engine that has sat for 2 or 3 days situation. Thanks!
I recently converted my '73 slant-six Valiant from it's original and leaking Holley 1920 to a 1945.
I know everyone has their own opinion of each carb, but I'm 100 percent glad I did it. The 1945 runs better all the way around and eliminates what I consider design deficits that the 1920 has, primarily potential for leaks, parts availability and a better accelerator design.
The carb I used came from a 1984 Dodge van, no Lean burn. I had to drill and tap the carb for an idle screw since the van used an idle stop solenoid. I also have a '75 1945 and I attempted to hybridize the positive return base off the earlier carb with the body of the later carb, but there are simply too many differences in the way the accelerator pump works between the two.
I also used the 1945's electric choke, which fit right on, and best of all it's over-the-valve cover metal fuel line which repositions the fuel filter down alongside the block on the passenger side.
Here(finally) is the only issue I have:
After sitting 2 or 3 days, the fuel is obviously siphoning back out of the carb. It takes about 2 or 3 5-second cranks before the engine catches and runs, COLD. Hot there is no problem.
It's not flooding into the engine because I checked and the carb throat is dry. It has a brass float which is adjusted properly. The choke is also working properly.
The 1920 would do this occasionally, but it had to sit a couple weeks first. I am speculating if possible my fuel line arrangement at the pump is contributing to, if not causing this issue. I'm pretty sure the van had a short metal segment which exited the pump, curved downward and back up in a 180-degree loop, then entered the fuel filter which was of course mounted with rubber line segments. I think I've seen that on V8 cars also.
I'm interested to hear if anyone has made a connection between loops in the line and drain back problems.
Also, to recap, this has NOTHING to do with hot engine operation. It is strictly a cold engine that has sat for 2 or 3 days situation. Thanks!
