Author Topic: Drt-08 209 fixing  (Read 977 times)

Articifer Tom

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Drt-08 209 fixing
« on: April 18, 2020, 08:43:20 PM »
Hello All .  I been working on my 209 carb to get it working . Had it rebuild and was done with incorrect RJH parts . Been working on a year , on and off along with some others with same rebuild on AACA site . I determined idle tube need to have lower jet hole increased and inside jet restriction reduced . Just doing that got it starting and running . Did not road test was Winter , at time .  Disassembled again since repaired exhaust and manifold leaks. Want to check out specs of orifices in replaced standpipe and cone . From some holes in top of pipe missing and parts near bottom not reinstalled . Are ther not need now ??? Attached is pic of pieces and spring with questions I have . Any help would be appreciated .
  I think Frank29u did some work on his years ago , any input please .

frankp

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Re: Drt-08 209 fixing
« Reply #1 on: April 20, 2020, 08:21:49 PM »
Tom, not much help here.  Only thing I've done with carbs is disassemble what I could and use cleaner and air to blow through orifices.
frank p

Articifer Tom

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Re: Drt-08 209 fixing
« Reply #2 on: April 20, 2020, 09:15:08 PM »
Thanks , after some study . I believe that whole bottom mechanism is related to choking the air to going up inner stand pipe .
   As   choke is moved and as it progresses up ,it closes off and cone then blocks outer venturi area . Probability only needed in most extreme cold ,sub freezing . Only effect now ,is  you need full or near full choke pull to get any . An this is what drivers describe when starting rebuilds . The top pipe hole are probability related to high accel . not choke . To add the components back in bottom would require machining a larger partial depth hole in SP to recess small spring . And side slots milled for brass bracket . Large spring and collar ,must just buffer return .

frankp

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Re: Drt-08 209 fixing
« Reply #3 on: April 20, 2020, 10:03:28 PM »
My sedan is finicky and sometimes needs a brief full choke if it hasn't run in a while.  Just not excessive.  Seems to be ambient temperature dependent too, adding another variable.
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chetbrz

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Re: Drt-08 209 fixing
« Reply #4 on: April 21, 2020, 10:22:52 AM »
Tom,

I don't understand the issue with the chock.  My understanding is when you chock the carb you are decreasing intake air flow which creates added lift pressure on the venturi tubes causing more gas to be sucked into the engine.  If you chock too much you flood the engine ?  The diameter of the venturi tubes determine the amount of gas flow based on your engines need or cubic inch capacity.  The 209 was for the 31 PA which was a 196.1 cu. in. engine.  The earlier RT-08 was for a 175.4 cu.in. engine.  DRT-08 I believe for Dodge.  There were different jet tube sizes whether a Ply, Chevy etc.   

If the idle tube is two large the idle air volume of the engine will not be able to lift enough gas to produce a steady idle speed.  If you need to chock the engine to run at idle than the tubs are incorrect for your engine.  If you had drilled the holes out to increase flow I believe this to be a mistake.

My 2 cents.
http://www.1948Plymouth.info           Web Master - Forum Administrator - AACA member

Articifer Tom

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Re: Drt-08 209 fixing
« Reply #5 on: April 21, 2020, 12:27:18 PM »
No my engine idles fine without choke , it's adjustablity . When carb was rebuild they used and idle tube and standpipe from Chevy RJH a smaller carb for smaller engine . Nobody sells correct parts .
    I simply drilled the idle jet ( bottom ) hole to same size as DRT209 jet . The top horizontal hole ( bypass) for air was correct size . The hardest was inner vertical restriction ( economizer) .  That had to be reduced from drill size #53 to #56 . That reduction is probability done with a tool similar to knurl er . I hand rolled and did get it reduced , but broke in process so then silver soldered back together . I went though this extra step to get my carb idle adjustment to be in a sweet spot to adjust . I have not yet reassembled to test . My carb ran with screw closed to 1/4 open best and it should be coming out more . Also this larger volume of mixed fuel also kept idle higher . With out that full adjustment it is hard to tell if I am truly adjusted the best it can be .
   At same time I noticed the other missing parts and fact of missing holes in standpipe that are in DRT's
I figured while apart to get it back as much as possible to original DRT spec . 

ehenin

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Re: Drt-08 209 fixing
« Reply #6 on: April 24, 2020, 05:02:28 PM »
just a question, is this a 209? I  think it is anyway.

Articifer Tom

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Re: Drt-08 209 fixing
« Reply #7 on: April 24, 2020, 06:50:26 PM »
Yes it looks like one . Only sure way to tell is remove bowl and get idle jet , well jet and multi jet numbers from the exposed buttons . With them I can look up in book .

frankp

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Re: Drt-08 209 fixing
« Reply #8 on: April 24, 2020, 06:51:05 PM »
I say yes.  Great looking accelerator pump!  As everyone knows, that pot metal can be fragile.   frank
frank p