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Tuning ‘55 322 issues


jw1955buick
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Ok, I stink at tuning, always have, every old car I ever had ran too rich and was hard to start, this one is no different

whats been done: rebuilt 322 with some type of RV slightly lumpier than stock cam, no info available, rebuilt carb, new coil, cap, plugs, wires, points, condenser, fuel pump, vacuum lines

the rebuild was 8 years ago and driven very little because of electrical issues that were never resolved, something draining the battery 

so I rebuilt the carb recently, replaced most ignition components, checked the gap in the points, timed it to 5 degrees, mixture screws out one turn, problem is it still runs rich and fouls the plugs, is hard to start when cool even with choke closed and seemingly working, sounds like a slight miss or vacuum leak

so compression is good and consistent, put a vacuum gauge on the port between the mixture screws, plugged the vacuum advance on dist, warmed up the engine and the gauge is showing 28 steady but when I kick down the throttle to around 500 rpm the gauge goes to 8 and stays there unless you get back in the throttle, I get no real change in vacuum by moving the dist unless I move it pretty far,  mixture screws make no difference in idle even if turned all the way in

seems like a vacuum leak from what I’ve read but I can’t figure out where it would leak at, checked all hoses and fittings 

the plugs always seem to be fouled so I feel like I’m in some time loop that I can’t get out of, don’t know if that port in the carb is the right place to measure vacuum but I don’t know where else you’d put it unless you drilled a fresh hole in the intake 

 

help please 

Edited by jw1955buick (see edit history)
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So the vacuum source for the distributor is a nipple at the base of the carb between the mixture screws, this is how I inherited it.

1  is this the factory vacuum source location for this setup 

2. If not, then what? And how and exactly where would you obtain the right source of vacuum to put a gauge on it?

 

it does have vacuum wipers with a line to the bottom of the two part fuel/vacuum pump2A9CE867-5FFE-4FB3-A1FF-1A025349A587.thumb.jpeg.ff095dbc2acfaa9adb73a5123686ecb2.jpeg

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Going out on a limb here, but, see that turquoise pipe threaded into  fitting threaded into the intake manifold just under the black vacuum hose in the picture? That is the vacuum source to the fuel pump vacuum section, which in turn provides vacuum to the wipers.

 

No need to plug the vacuum port on the vacuum advance, when the hose is disconnected. It is the hose or the port on the carburetor that needs to be plugged, as it should have vacuum on it at some point in time.

Edited by Frank DuVal (see edit history)
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Frank, that makes sense, so where should I splice in the vacuum gauge?

 

also I blew air through every tiny idle circuit hole I could find when I rebuilt the carb, pump, fuel line, tank all clean on start up, glass filter bowl is clean, no sign of any sediment anywhere 

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14 hours ago, 1956322 said:

If the idle mixture screws have no affect then most likely the passages are clogged

 

1 hour ago, 1956322 said:

What speed is it idling at?

If idling too fast the mixture screw have no effect...try again at 500 rpm.  Study that carter(?) carb in the service manual; blowing will do nothing if deposits are stuck...needs to be soaked!

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I did all that, total carb soak and rebuild per shop manual, I did everything but pull the shafts and remove butterflies, used the kit from CARs, it's possible that a piece of something is in there of course but unlikely considering that I went through the entire fuel system. 

It's improving as I go, it now at least stays running at 500 just not smooth, installing clean plugs over and over not knowing how quickly they foul and affect the idle, as always, it smooths out for the most part with increased throttle.

 

Any thoughts on choosing to time for max vacuum vs timing at the 5 degree mark per the manual? Pros? cons? terrible idea?

 

What's the original location for the distributor advance vacuum source? Pictures??

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13 hours ago, jw1955buick said:

2A9CE867-5FFE-4FB3-A1FF-1A025349A587.thumb.jpeg.ff095dbc2acfaa9adb73a5123686ecb2.jpeg

 

This is the carb you soaked and rebuilt?

The rubber tube should go to the vacuum advance.

I time all of my nailheads at 7* btdc at 350 rpm; you should an additional 10* when you raise the rpm (from the mechanical advance) and an additional 10* from the vacuum advance when connected

Check the dwell when running and at different rpm.

What brand and plug are you using?  Autolite  85 will serve you well.

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If the engine is running rich, why the concern about a plugged carburetor passage???

 

When the engine is totally warm, is the choke butterfly completely open (vertical)?

 

Fuel pressure at the carburetor?

 

Cannot tell from the picture: does that carb have the idle vent, and if so, is it functioning correctly?

 

Condition of grounding strap to engine block, and/or body?

 

Are the new wires resistor (carbon) or copper wire?

 

No offense meant, when you did the rebuild, did you get the pump discharge check valve in the correct spot?

 

It is possible you have multiple issues: (1) the rich idle, and (2) the hard start cold.

 

Jon.

Edited by carbking (see edit history)
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All things point to the carb. Specifically no change when the mixture screws are all the way seated.  With that said, is it possible a check ball or small internal piece was missed when rebuilt?  I say this because I have turned over carbs when working on them only to find a mystery check ball on the work bench.  

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I am just going to pipe in here. I had similar issue of running rich. I rebuilt the carb and issue gone. Not saying that is your problem but did you use compressed air to blow out all the passages after soaking the carb body in cleaner?  Also, whoever last dealt with my carb had the choke incorrectly set. You need to abide by the shop manual and set everything correctly.

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It may be the carb, it may not be.

 

As old-tank pointed out in an earlier post; if the engine is idling too fast, the idle screws will do nothing. One can screw them all the way in, or take them out and put them in one's pocket, there will be no change.

 

Either there is too much fuel, or not enough spark; tests will determine which it is.

 

Too much fuel could be caused by excessive fuel pump pressure, or the choke not going completely off, or a sunk float, or a missing accelerator pump discharge check valve, or maybe something else.

 

Too little spark could be caused by the new wires being carbon, or a defective ground through the ground strap, or maybe a defective voltage regulator, or?

 

Of course, if the consensus is a defective carb, I know a really good source for carb kits ;) I just don't believe the OP has exhausted enough possibilities to rebuild a previously rebuilt carb.

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So I’m not a good carb rebuilder apparently, I’m not getting a good squirt of fuel when actuating the throttle linkage, I’ll get one squirt and not a good one then bubbling and dribbles 

when it’s warm and you try to start it, acts like it’s out of gas so fuel is not getting in steadily for sure 

I found my float level is too low so work to do there, also is there supposed to be a spring under that vacuum piston that controls those metering rods? That T shaped rod bar is all the way up all the time with that spring underneath it, that’s how it was when I took it apart so I put the new provided spring back in there, something about it doesn’t seem right, that little hook on the accelerator pump shaft seems unnecessary with that spring in place 

I realize these are all very basic questions, I’m trying to learn this stuff 

 

and there’s plenty of fuel in the glass bowl the whole time so I don’t think it’s fuel delivery issues to the carb

Edited by jw1955buick (see edit history)
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13 hours ago, carbking said:

One can screw them all the way in, or take them out and put them in one's pocket, there will be no change.

 

When Detroit switched to downdraft carburetors the dealer network service manager requested lots of screws and adjustments for the carburetor. Lots of them right under the owner's nose just tempting him.

 

I would make sure I got it running on the idle circuit. You can do that by looking down the throat of the carb when it is running and making sure fuel isn't dribbling onto the throttle plates. Close the plates until that stops. If it doesn't stop, address the level issue. If it does stop at least you will be on the idle circuit and there's not much to scrutinizing that.

 

Wasn't there an initial drill bit size to use as a gauge to preset the throttle plate opening?

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1 hour ago, jw1955buick said:

So I’m not a good carb rebuilder apparently, I’m not getting a good squirt of fuel when actuating the throttle linkage, I’ll get one squirt and not a good one then bubbling and dribbles 

when it’s warm and you try to start it, acts like it’s out of gas so fuel is not getting in steadily for sure 

I found my float level is too low so work to do there, also is there supposed to be a spring under that vacuum piston that controls those metering rods? That T shaped rod bar is all the way up all the time with that spring underneath it, that’s how it was when I took it apart so I put the new provided spring back in there, something about it doesn’t seem right, that little hook on the accelerator pump shaft seems unnecessary with that spring in place 

I realize these are all very basic questions, I’m trying to learn this stuff 

 

and there’s plenty of fuel in the glass bowl the whole time so I don’t think it’s fuel delivery issues to the carb

 

Sounds like a carb issue from your description.  There should be a healthy squirt of fuel from the accelerator pump if the correct accelerator pump was installed.  If the float is low there is an issue certainly.  If I recall correctly, yes, there is a spring under the metering rods that keep them up.  If there is a hook there is a reason for it.   The T shaped bar(metering rod) can be installed backwards.  I know cause I done it.   The carb needs to be gone over again from the sounds of it.       

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This is a Carter 2 barrel. Would think the set up of the meter rods is the same as the big brother Carter you have.   There is a hook protruding that needs to be on the correct side.  Like I said, I installed mine backwards.   This picture saved my bacon in getting it installed correctly.aYjOtLE.jpg 

 

   

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Quote: ""I’m not getting a good squirt of fuel when actuating the throttle linkage, I’ll get one squirt and not a good one then bubbling and dribbles 

when it’s warm and you try to start it, acts like it’s out of gas so fuel is not getting in steadily for sure"

 

Could be a function of the pump check valves not working correctly, a modern non-leather accelerator pump that has already failed in modern fuel, pump cup leather incorrect size, or "turning upside down". The check valves not working correctly can make the engine run rich all of the time.

 

Quote: "I found my float level is too low so work to do there"

 

This is going to make the engine run very lean, if at all.

 

Quote: "also is there supposed to be a spring under that vacuum piston that controls those metering rods?"

 

Yes, the spring counter-balances vacuum. When the engine is off, the spring pushes the piston up. When the engine is running, the engine vacuum pulls against the spring, and the two working in conjunction control the height (therefore the metering step) of the metering rods in the jets. The higher the vacuum, the lower the rods are located in the jets (on the thickest part). When the vacuum goes to zero under wide-open-throttle conditions, the spring pushes the linkage and the rods up, and the rods will have the smallest diameter sticking into the jet.

 

As old-tank mentioned, the factory service manual is a good place to look for understanding. Also, a diagram FOR YOUR SPECIFIC CARBURETOR, from the factory Master Parts Book. If you got a generic set of instructions with a generic diagram in the kit, place it in your parrot cage (I can't spell parakeet) where it belongs! If you still have outdoor plumbing, it can be used in lieu of the Sears & Sawbuck catalogue!

 

Factory Carter literature is also quite useful, if you can find the page FOR YOUR SPECIFIC CARBURETOR.

 

Jon.

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Yes, definitely sounds like you will need to pull it and start again. Study the shop manual or read the relevant 'Hometown Buick' webpage for the carb. This will be especially important for the choke settings. You may also like to see if you can find youtube video of a rebuild for the Carter as that will assist. Compressed air to clean out every passage after soaking in a good carb cleaner. Not sure about the Carter but the Rochester has apparently 3 different accelerator pump diameters so make sure you have the right sized replacement as you won't get good fuel delivery if there is insufficient seal.

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5 hours ago, 60FlatTop said:

 

When Detroit switched to downdraft carburetors the dealer network service manager requested lots of screws and adjustments for the carburetor. Lots of them right under the owner's nose just tempting him.

 

I would make sure I got it running on the idle circuit. You can do that by looking down the throat of the carb when it is running and making sure fuel isn't dribbling onto the throttle plates. Close the plates until that stops. If it doesn't stop, address the level issue. If it does stop at least you will be on the idle circuit and there's not much to scrutinizing that.

 

Wasn't there an initial drill bit size to use as a gauge to preset the throttle plate opening?

 

Actually, many of the older updraft carbs had significantly more adjustments than the downdraft carbs.

 

Virtually all updrafts would have:

 

(A) Idle mixture

(B) High speed mixture

(C) Curb idle (RPM)

 

These are the same basic adjustments found on most downdraft carbs.

 

Additionally, many updraft carbs had:

 

(D) throttle opening adjustment (yes, you could limit the opening of the throttle plate, Wouldn't that be useful when your 16-year-old got their license ;) )

(E) Dash adjustment for the auxiliary air valve.

 

And many (most?) late 1920's updrafts also had an adjustment on the amount of the accelerator pump shot.

 

Jon.

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From experience, there are some deposits that will NOT be removed by soaking.  They will have to be removed "mechanically", if at all.  BUT if they were in the idle and main system tubes which are on the "fuel side" of things, those deposits will restrict fuel flow and cause a lean condition (which will also prevent sufficient fuel getting into the venture for the engine to run.

 

Are there any small holes on top of the venture cluster?  IF their placement coincides with the smaller, solid brass tubes which go into the fuel side of things, then those air bleeds are calibration points in the fuel mixture curve for the idle system.  As they clog or are restricted, the idle circuit goes "rich".  Just spraying carb cleaner or blowing them out with air is not enough to get them cleaned out, from my experiences.  You might probe them with a very small wire to see if they are fully open.  The larger holes are for the main system, not affecting the idle mixture fuel curve.

 

In order to determine the size of the hole, you might try using a bent-wire spark plug gap gauge, to see which of the smaller sizes might or might of might not fit the hole.  With that size in mind, you can go to the hobby shop and get some twist drills of that size range.  Then gently probe/enlarge the restricted hole until you "get metal shavings".  KEY thing is to not enlarge the hole from the OEM size!  But clean it out just to that point and NO LARGER.

 

Now, I'm not fully aware of how that particular carb is designed.  But knowing how later Carter 2bbls and 4bbls were designed, I do know about, which is where my main knowledge is.  The air bleeds are part of the total fuel calibration curve of the carburetor, although the metering jets and such are what people generally think about when the subject of fuel curve is mentioned.

 

HOPE this might help,

NTX5467

Edited by NTX5467 (see edit history)
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It’s handy that I’m taking guitar lessons, I used a bit of that string to probe everything I could find, my choke pull off adjustments are getting better as I’m understanding the terminology in the shop manual, floats are now within a 16th of spec, that’s some stressful stuff bending those things 

I don’t know how to test the accelerator pump without installing it and running it which is fine, just takes time 

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23 minutes ago, jw1955buick said:

test the accelerator pump

Just fill the cavity with WD40 and push down on the loose pump.

Note that the float settings are done with the gasket OFF, which means that the floats will have to be removed to put the gasket back on.  I use appropriate size drills to set the floats instead of those supplied cardboard things.

Don't  swap or mix the main metering jets...the primary and secondary are not the same. Even if put back to where they were located, someone may have "messed with it" before (page 62 of service manual).

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41 minutes ago, jw1955buick said:

are getting better as I’m understanding the terminology in the shop manual

 

A couple of days ago I was talking about my friend, Mike, who passed away three years ago. He would use incorrect terms and be misunderstood. I would tell him "You can't call it that". He would always reply "Well, that's what "I" call it". But, Mike, it doesn't work that way.

 

What I wrote about updraft to downdraft was an untruth for illustrative purposes. I tried to make it lack credibility, make it bristle with adjusting screws to be irresistible.

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IF you plan on painting anything NEAR the place the silicone spray is deployed OR it might land, better get some "fisheye" additive for the paint being used.  Or a liquid to remove the silicone from the surfaces being painted.  Grease will work as well without the painting issues, I suspect.

 

NTX5467

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1 hour ago, NTX5467 said:

IF you plan on painting anything NEAR the place the silicone spray is deployed OR it might land, better get some "fisheye" additive for the paint being used.  Or a liquid to remove the silicone from the surfaces being painted. 

 

How true, that stuff is a horror story in body shops. Used car lots would use silicone spray to detail cars, then if that didn't work, they would send them to my shop. I had to buy a hot water  pressure washer with strong detergent suction hose to clean the cars, including the engine compartment to get paint work done without fisheyes in it AND other cars sitting nearby!😡

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  • 3 weeks later...

Welp, the Metering rod bar was in fact backwards, I guess that'll throw off the vacuum piston geometry or doesn't let the rods seat properly or who knows, it just works one way only.

so now it starts good, doesn't foul plugs and idles better, not great but much improved

 

thanks all for the sage advice

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11 hours ago, jw1955buick said:

Welp, the Metering rod bar was in fact backwards, I guess that'll throw off the vacuum piston geometry or doesn't let the rods seat properly or who knows, it just works one way only.

so now it starts good, doesn't foul plugs and idles better, not great but much improved

 

thanks all for the sage advice

 

 

Even with my pictures I managed to install the metering rod backwards when I reassembled!  Sometimes these things get the best of us.  Glad you have it sorted! 

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  • 3 weeks later...

Not really sure where I’m at with these adjustments, got as close as I could with trying to make sense of the shop manual, please look at the pictures  see if action and position of fast idle cam and the choke parts looks like it should 
first picture, car is cold, nothing happening 

 

second, I’m holding choke valve open 

 

third, throttle pulled all the way on

F62EAAA6-7FFF-4B3B-9FBD-2D2571A898CB.jpeg

D11FA3BC-DE51-4B6A-955A-6DDF5571A75E.jpeg

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  • 2 weeks later...

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