Re: [Chrysler300] 375 Troubled Horses

[lettercars@xxxxxxx]

All:
Both the 1957 Service Manual and the AMA (Automobile Manufactures  
Association) specs agree----The 300C radiator pressure cap should be a 14psi  unit.  
Both AC and non AC.
300ly, Gil C.
 
 
 
 
In a message dated 8/16/2011 7:13:44 P.M. Eastern Daylight Time,  
thelastbestgenius@xxxxxxxxxxx writes:


1)  Someone else has already suggested what it sounds like - namely that 
the  system has lost pressure after turning off - and with no pressure, it 
boils  due to masses of heat coming out of large volume of hot cast iron etc  
!!?

BUT BEWARE IF CAR STILL FITTED WITH ORIGINAL HONEYCOMB TYPE HEATER  CORE - 
too high a radiator cap pressure often bursts perfectly good but old  core.

SO QUESTION 1 - what is factory correct pressure for '57  300C?  (10, 12, 
other lbs?!)


2) Does anyone still supply the  leather type accelerator pumps for both 
our 50s period Carter and Rochester  Carbs. 
300C used them, and a friend's Packard with Rochester 4GC needs  one. And 
here is the 300C/B relevant part - boy that single 4bbl biggest cube  Packard 
V8 has some 70+mph highway passing ooomph - be interesting to run a  '56 
300 and one of them side by side at say 60-90mph and flor them and see how  
they compared?! Anyone ever done it?!
But back to the question - anyone  supply the name of US Company still 
doing leather accelerator pump  plungers?

Christopher in Australia - backyard lawn under 3 inches of  water, weather 
not very 300ly here lately!! 




To:  lorencnelson@xxxxxxxxxxx
CC: Chrysler300@xxxxxxxxxxxxxxx
From:  kboonstra@xxxxxxxxxxxx
Date: Tue, 16 Aug 2011 18:12:30 -0400
Subject:  Re: [Chrysler300] 375 Troubled Horses






Several of you suggested that the floats and needle valves  were the 
place to look for the cause. Turns out you were right. One of the  
float pairs in the primary (rear) carb was incorrectly set by the  
rebuilder. At least I doubt that shaking in transport could have bent  
them if they were correctly set to begin with. The bottom line is  
fixing that float level cured the problem and I thank all of you for  
your help.

Here's the next question:
Why would my radiator boil  out the overflow tube after shutting down 
under certain (not all)  conditions? Here's the scenario: Ambient temp 
about 80 degrees, 20 minute  highway ride at 80mph, shut down for 10 
minutes (no overflow), started and  drove low speed for 2 minutes, idled 
for 5-10 minutes in neutral and shut  it down. It boiled out the 
overflow tube. Registers about 3/4 to the hot  mark on the dash gauge

Everything is fresh - engine, water pump,  radiator core, and 14 lb. 
cap. The thermal fan clutch is not new but  worked fine before. 
Ignition advance is 5 degrees. Is there a way to test  the fan clutch 
for proper performance? Where else could I look for a  source of the 
problem? Radiator cap not actually holding to 14psi? (I will  check that).

Thanks.
Keith Boonstra

-
On 8/11/2011 1:07  PM, loren nelson wrote:
> It sounds like a leaking float needle valve or  incorrect float level. 
> I just had the same problem on my G. I think  the carbs are similar to 
> the AFB on the G and there are 2 needle  valves on each carb. This 
> doubles your chance of a leak. At high RPM  the engine consumes the 
> fuel faster than the leak, but at idle the  leak adds more fuel than 
> the engine consumes and it floods.
>  There could be gas leakage at the base of the offending carb, but with  
> all new gaskets there may not be any leakage. You may have to wait  
> until it stalls and remove the carb tops to see which one has the  
> highest fuel level. The floats should all fall the same distance from  
> the top and when lifted should stop at the same distance from the  top. 
> If the floats look good, you have a leaking needle valve. It  could 
> just be a piece of dirt in it but you may need to replace the  needle 
> and seat. I fixed mine by cleaning them up with some very fine  emery 
> cloth but that will not work with the rubber tipped  needles.
> Good luck,
> Loren in Hotlanta
>
> -----  Original Message -----
> *From:* keboonstra  <mailto:kboonstra@xxxxxxxxxxxx>
> *To:*  Chrysler300@xxxxxxxxxxxxxxx
>  <mailto:Chrysler300@xxxxxxxxxxxxxxx>
> *Sent:* Thursday, August  11, 2011 10:21 AM
> *Subject:* [Chrysler300] 375 Troubled  Horses
>
> Would someone who knows a whole lot more than I do  about WCFB
> carburetors try to help me out? The car is a '57  300C.
>
> Basically what I've got happening on my freshly rebuilt  carbs is
> that I can't get the engine to idle without flooding out.  I've
> tried to follow the book and set the idle mix and air mix  screws
> on both carbs at 1 turn out. Then I followed another  expert's
> advice to put them all at 1-1/2 turns out, and yet  another
> recommendation I heard which said you should close the  idle
> circuit screws on the forward carb completely and set up the  idle
> on only the rear carb.
>
> I've spent hours  tinkering, but no matter what I have done the
> engine always dies when  I let off the throttle below something
> like 700 rpm. The only way I  can then restart the warm engine is
> to hold the throttle wide open  while cranking until the manifold
> clears after about 20 seconds of  grinding. The engine then
> gradually struggles and coughs back to life.  There's so much fuel
> in the manifold when it dies that I have to keep  the the air
> cleaners on during restarting just to keep flames from  licking out
> of the tops of my carbs. I've learned to keep a towel  handy to put
> the fires out.
>
> When the above attempts  did nothing to help the flooding, I shut
> down the idle mixture and air  mix screws on the front carb, and
> then tried turning in the rear carb  mixture screws until they were
> all but closed while opening the air  mix screw as far as 2-1/2
> turns. But no matter what I do the engine  always quits and the
> manifold always loads with fuel. And BTW, I can't  blame the fuel
> octane as I'm using 100LL aviation fuel for the  setup.
>
> I'm pretty green when it comes to carburetor tweaking  so I'm
> really baffled as to where to look next for the solution. Why  is
> it running so rich? The choke plate is wide open with the  engine
> warmed up to operating temp, and yet I have to go wide open on  the
> throttle during the cranking to clear it out before it will  run.
> And even then it doesn't run very well.
>
> And  here's my rant. I REALLY want to hit the road a bit with this
> car, but  it's fighting me every step of the way. I've only gotten
> to rack up 10  fitful miles so far since the restoration. I've had
> to track down and  fix leaks of every single fluid the car has,
> even though everything  has been rebuilt - gas, engine oil,
> coolant, brake fluid, transmission  oil, PS fluid - along with any
> other problem you can imagine. It drove  me nuts. The only things
> that haven't leaked are the tires and the  battery. So after
> getting all these issues fixed, I really didn't need  a carburetor
> problem on top of it all.
>
> Well anyway,  where do I look next? Float levels or or incorrect
> jets or something  else? Shall I limp it over to my engine builder
> who does a lot of  carbureted engines - including race engines?
> They claim to have some  "tricks" they know how to perform on the
> WCFBs. What else can I  do?
>
> HELP !!!!!!!!!!!!!!!!!!!!!!!!
>
>  Thanks.
> Keith Boonstra
>
> 
>

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