Author Topic: Definitely NGC- Help with old '64 Chevy truck  (Read 2913 times)

Offline boatdetective

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Definitely NGC- Help with old '64 Chevy truck
« on: March 20, 2016, 09:05:14 PM »
My cuz bought an oldie but goodie. Ancient chevy with what i believe is a 200-225 straight six. Has a single barrel Rochester.  The whole thing has been gone through by the PO. No- I don't have the details. Seems like the truck has developed a problem holding idle.  He can drive it around- but now it dies at idle.  Sounds to me like something may have clogged the idle circuit in the carb. Of course, I'll check the idle mixture screw- but it had been running OK and now it isn't-  doesn't sound like tuning.

Any thought son what would cause a sudden onset idle problem? Irritatingly enough, this is the same exact problem that I have with my ungrateful V50.  Once again- this is NOT a truck that has been sitting untouched for 30 years- the whole thing looks rebuilt and it had been running fine.  My cousin tries to start it up an run it once a week, FWIW.

Any thoughts?
Jonathan K
Marblehead, MA

1981 V50III "Gina"
2007 Griso 1100 "Bluto" (departed but not forgotten)
2003 EV "Lola" gone to the "Ridin' Realtor" in Peoria
2007 1200 Sport "Ginger"

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Offline guzzisteve

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #1 on: March 20, 2016, 09:18:56 PM »
I would check the points in distributor, just an Idea.
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Offline boatdetective

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #2 on: March 20, 2016, 09:22:15 PM »
Thanks, Steve.   .but what would I look for? (I've never dealt with points)   Would they be worn?
Jonathan K
Marblehead, MA

1981 V50III "Gina"
2007 Griso 1100 "Bluto" (departed but not forgotten)
2003 EV "Lola" gone to the "Ridin' Realtor" in Peoria
2007 1200 Sport "Ginger"

"Who's the cat who won't cop out, when there's danger all about?"  -Isaac Hayes

Offline RinkRat II

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #3 on: March 20, 2016, 09:25:30 PM »
 Hey there Boatdetective, first thing I'd check for is a vacuum leak at the base of the carb and or the vacuum advance line to the distributor.
 Pretty reliable setup built for the long haul also new gas?? Carb may need some tweaking with a vacuum gauge. Easy to do on these.

    :popcorn:Paul B. :boozing:
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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #3 on: March 20, 2016, 09:25:30 PM »

Offline yogidozer

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #4 on: March 20, 2016, 09:30:05 PM »
vacuum leak?

Offline fotoguzzi

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #5 on: March 20, 2016, 09:34:04 PM »
64 Chevy truck? get pics, post here .......   :gotpics:
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Offline old head

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #6 on: March 20, 2016, 09:51:54 PM »
Hey there Boatdetective, first thing I'd check for is a vacuum leak at the base of the carb and or the vacuum advance line to the distributor.
 Pretty reliable setup built for the long haul also new gas?? Carb may need some tweaking with a vacuum gauge. Easy to do on these.

    :popcorn:Paul B. :boozing:

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HardAspie

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #7 on: March 20, 2016, 09:52:57 PM »
A small vacuum leak can sometimes be identified by spraying something non flammable like a spray cleaner around carb base gasket. You will see no bubbles, but the fluid can temporarily seal the leak and make idle better. Could also be advance curve on distributor...need timing light and dwell tach.

Offline Sasquatch Jim

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #8 on: March 20, 2016, 10:51:12 PM »
  Other than gremlyn poop in small passages, (varnish buildup), the pivot point of butterflies and choke and such can get worn and admit air which will definitely affect idling.  With the engine running, probably one hand on the throttle so it doesn't die, spray WD 40 or some other light oil on those pivot points and on the gaskets.
 If the engine smooths out a bit then you know what the evil gremlyn is.  Gaskets can be replaced or resealed
 but worn pivot points may mean replace the carb.  J.C. Whitney or some other catalog will have what you need.  For points, look for pitting of contact surfaces, proper gap and dwell and of course timing.
 Points condenser ignition is not rocket science and a manual should enable you to do what is needed step by step.  Replacing the condensor is always a good idea when doing this.
 At least on that old in line six you don't need to be a contortionist to reach everything.
« Last Edit: March 20, 2016, 10:53:12 PM by Sasquatch Jim »
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oldbike54

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #9 on: March 20, 2016, 11:13:49 PM »
 Would be the 230 CI Chevy , not a bad motor . OK , so it was running fine and then developed the idle issue ? As suggested , check that the points are gapped properly , then check for air leaks . Also , no matter how rebuilt it looks , it may have a bad timing chain , a sticky hydraulic lifter , or a leaky head gasket . At least with the 230 motor parts should not be a problem . I might also check what the gasoline looks like at the filter .

 Dusty

Offline eldoroddo

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #10 on: March 20, 2016, 11:47:12 PM »
My '67 Buick V8 has heat passages in the intake manifold to "help" the engine warm up.
Owners usually block them off because they cook the gas in the bowl (no carb spacer of any sort).
Also check that the hard fuel line isn't close to the hot engine or exhaust manifold.

Penderic

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #11 on: March 21, 2016, 04:52:28 AM »
Also be aware of the mechanical fuel pump .... the mechanical types have a rubber membrane that can be affected by the ethanol in gas.

I have read a couple of stories about those older fuel pumps leaking and causing fires.

Offline Zoom Zoom

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #12 on: March 21, 2016, 05:01:24 AM »
The vacuum leak is the first thing I thought of also. What I have always done is to use some starting fluid to locate the leak. Spraying it around the carb and vacuum lines will identify a leak right away. The engine will speed up as soon as it gets some ether. It could be as simple as a hose that has come unplugged from a manifold nipple too.

EDIT: Another source for a leak could be the diaphragm in the vacuum advance on the side of the distributor. You would need to pull the hose off and put your thumb over the end of the hose to prove that one.

If you think that any vacuum driven device is the culprit, pull the hoses off the intake manifold and plug the fitting(s) with something. If it has an automatic transmission, the shift modulator also uses said diaphragm.
 

John Henry
« Last Edit: March 21, 2016, 05:25:44 AM by Zoom Zoom »

Offline Zoom Zoom

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #13 on: March 21, 2016, 05:36:06 AM »
Another note: I don't know if this applies, but a lot of GM carbs used a filter stone right behind a fitting where the fuel line connects. They would plug easily. I don't believe that would be your trouble since that would usually make itself known by starving fuel as the rpm increased. (Think, runs fine at 50 but runs out of fuel if you kick it down for passing.) Many of us would remove that filter stone and install a larger in line fuel filter near the carb. I mention this mainly for reference, but it is probably safe to assume there is a fuel filter there someplace, so I am thinking a plugged jet is unlikely.

NOW, if someone removed the filter stone and there is no filter in place, a piece of dirt in the carb could be highly suspect. So, if you do not see an external filter in the line between the fuel pump and the carb, you might want to remove the line and check for a filter stone. If no stone, then fuel has been going in unfiltered.

John Henry
« Last Edit: March 21, 2016, 05:37:59 AM by Zoom Zoom »

Rough Edge racing

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #14 on: March 21, 2016, 06:04:43 AM »
 Vacuum leak maybe, if the engine is stock, there's a hose/line running from the carb to the distributor vacuum advance and a 64 should have a PCV valve on the top rear of the valve cover with a hose from the valve to the intake manifold adjacent to the carburetor...Check the hoses... And the points as mentioned. The distributors in these engines are known to have wear problems...And it should have a Rochester B carburetor , check the idle mixture screw but it can have a obstructed idle fuel passage...And the obvious, maybe the idle speed screw needs an adjustment... ... The fuel tank is in the cab higher than the fuel pump on the engine.If the pump diaphragm leaks, the engine crankcase will flood with gas ... Usually will drip on the outside...
  More than any make, parts on older Chevys will interchange over many years  so it's hard to tell from here what's going on....A US  OHV inline 6 is the the most basic of engines and there's no mysteries to these...
   This is my daily driver except for the a few months during the winter.... 68 1/2 ton original four wheel drive, 292 6 cylinder and 4 speed manual, no power assisted anything...
         
       

       
     
« Last Edit: March 21, 2016, 06:07:28 AM by Rough Edge racing »

Offline Two Checks

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #15 on: March 21, 2016, 06:46:02 AM »
Ethanol may have affected the foat causing a high fuel level, slightly flooding the engine at idle. At higher rpm the carb won't flood.
At any rate check the float level.
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Offline boatdetective

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #16 on: March 21, 2016, 06:49:56 AM »
Somehow- I knw that i'd find plenty of experienced input here ;)  Thanks a lot guys!  This is all common sense stuff. As for the straight six- I absolutely love the lack of any fru fru doo dads.
Jonathan K
Marblehead, MA

1981 V50III "Gina"
2007 Griso 1100 "Bluto" (departed but not forgotten)
2003 EV "Lola" gone to the "Ridin' Realtor" in Peoria
2007 1200 Sport "Ginger"

"Who's the cat who won't cop out, when there's danger all about?"  -Isaac Hayes

Offline guzzisteve

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #17 on: March 21, 2016, 07:29:53 AM »
Chevy strait 6 is pretty basic stuff, easy to maintain and run forever. Had lot's of them over the years. 230's in cars and 292's in farm trucks C20 & C60 and also in the White combine.
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Offline LowRyter

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #18 on: March 21, 2016, 09:05:30 AM »
Nice looking truck RER   :thumb:
John L 
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LaMojo

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #19 on: March 21, 2016, 01:17:23 PM »
If it is a 3 on the tree, be sure to have a coat hanger handy to un-jamb the shifting linkage.

oldbike54

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #20 on: March 21, 2016, 01:25:15 PM »
If it is a 3 on the tree, be sure to have a coat hanger handy to un-jamb the shifting linkage.

 Yep , and a hammer for when the ball joints go all woogity  :laugh:

  Dusty

Rough Edge racing

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Re: Definitely NGC- Help with old '64 Chevy truck
« Reply #21 on: March 21, 2016, 04:35:20 PM »
If it is a 3 on the tree, be sure to have a coat hanger handy to un-jamb the shifting linkage.
There's a free play adjuster under the hood on the column....... However. if there's no more adjustment  I could always pick up on the first/reverse lever with a finger.......But... if the parking brake didn't work sometimes ya had to rock the vehicle back and forth a bit to take the load off the gear so it would pop back up in neutral..Saving money to buy a Hurst shifter.... And in V8 vehicles the howl the three speed made as it wound out....And at the salvage yard on Saturday morning pulling a trans to replace the one with a blown first gear after Friday night street racing.

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