68 New Yorker 440 is out of tune

68-NewYorker

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Recently, my Holley 4160 carb started leaking with some older gaskets so I rebuilt it with the blue gaskets, soaked it and had every part out on the table. I set the float per specific measurements and all that. So when I put it back on the 440 and set the idle screws (backed out 1 1/2 turns), it is having problems running. I need to fine tune it and set the timing but I don't have all the "factoids" to do it:) I watched some videos, but its not that easy.
It starts great when cold on the first couple attempts every time. However, once it warms up, it stalls on its own. The idle does not settle down with a pump of the throttle. Also, it is too rich as it starts fine, but gets richer each minute. Then it will have trouble starting and even backfire. New plugs, new wires, new fuel, new distributor but not sure about choke adjustment, idle screws and the order I should be making each adjustment. Can't take it out for a drive like this so I was checking with the best by getting on here.
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Davea Lux

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Start the car up and let it run for a minute or so and shut it off, remove the top of the air cleaner and look down the bores of the carb with a flash light. Do you see fuel dripping from the air horns? If so, you have a bad needle valve, bad float or the float is improperly adjusted. Remove the bowl from the carb from which ever side of the carb is leaking. Remove the float and inspect the needle valve for debris under the seat. If that is clean, shake the float to see if there is fuel inside of it. The modern blended fuels go corrosive if the vehicle is left sitting any length of time and the corrosive effects of degrading fuel eats up the lead solder in the float seams and causes them to leak. If all of the above check out ok, recheck the float height and set to factory specs. Now put it back together. There is an idle screw on the driver side front of the carb, adjust until you get about 600 RPMs. Check the choke cam to be sure it is releasing with the choke open as that can also cause too high of an idle.

Dave
 
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CBODY67

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To add to what Dave mentioned, if the car was runnning decently well, but the carb had a fuel leak, then no real need to worry about the choke adjustments and such, UNLESS they might be causing an issue (which they usually don't as long as everything in their linkage is working as it should and is not binding-up).

Also, check to see that the choke valve is openning a bit when the engine first starts. If it remains closed, check the vacuum pull-off (on the passenger side of the carb) to see if it is working and the short length of vac hose to it from the carb metering block is not deteriorated or allowing a vacuum leak there. To verify its operation, gently remove the vac hose and manually compress the plunger with your fingers. Then use another finger to cover the end of the pull-off where the hose attaches. After compressing it, with the hole plugged/covered, release the plunger and see if the plunger moves outward. If it does, the choke pull-off probably could be one reason for the black smoke and such on cold start-up.

Get the idle speed and basic timing adjusted to specs and then do the idle mixture screws.

Please keep us advised,
CBODY67
 
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67 ragtop

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Recently, my Holley 4160 carb started leaking with some older gaskets so I rebuilt it with the blue gaskets, soaked it and had every part out on the table. I set the float per specific measurements and all that. So when I put it back on the 440 and set the idle screws (backed out 1 1/2 turns), it is having problems running. I need to fine tune it and set the timing but I don't have all the "factoids" to do it:) I watched some videos, but its not that easy.
It starts great when cold on the first couple attempts every time. However, once it warms up, it stalls on its own. The idle does not settle down with a pump of the throttle. Also, it is too rich as it starts fine, but gets richer each minute. Then it will have trouble starting and even backfire. New plugs, new wires, new fuel, new distributor but not sure about choke adjustment, idle screws and the order I should be making each adjustment. Can't take it out for a drive like this so I was checking with the best by getting on here. View attachment 489626

View attachment 489625
Your power valve gasket may not be seated on the power valve. I just had this happening to me, and I have been rebuilding Holly's for 50 years. this will allow fuel to leak /pour into the intake.
Leaky needle and seat check for fuel either dripping out of the boosters or coming out of the vents.
Did you set your float level dry only or did you set it again while running? It must be set while running.
On the needle and seats make sure you clean out the well where the needle and seat live. the new fuels will eat the O-ring and leave parts of it adhered to the wall. again happened on my last build. Take a q tip coated with carb cleaner and wipe out the bore. even a new needle and seat will leak if this happens.
 

live4theking

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If this is the factory 4160 you cannot adjust the floats wet. On the air horn the is a left hand thread adjustment. Did you take it out? The only place you find this adjustment mentioned is in the FSM. Do you have an FSM?
 

413

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Toss the Holley and get an AVS and life for the 68 440 will be much better.
Those factory installed holleys were junk from day one.
 

CBODY67

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Toss the Holley and get an AVS and life for the 68 440 will be much better.
Those factory installed holleys were junk from day one.

I have heard that for ages, but never could figure out why I didn't hear similar things from OEM Holley GM or Ford owners?

So, for curiousity sake, what made the OEM Chrysler Holleys "junk" and the others not junk? Was it the gaskets/seals or what?

Thanks,
CBODY67
 

Davea Lux

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I have heard that for ages, but never could figure out why I didn't hear similar things from OEM Holley GM or Ford owners?

So, for curiousity sake, what made the OEM Chrysler Holleys "junk" and the others not junk? Was it the gaskets/seals or what?

Thanks,
CBODY67

Several big issues:
1.) Bowl gaskets leaked
2.) Power valves or power valve gasket blew out if the engine farted back thru the carb, common on all big blocks.
3.) The velocity port for the vacuum secondaries was poorly located and often would not open the secondaries until about 3500+ RPMs, buy then the pass on the open highway was done.
4.) Carbs on a warm engine boiled over constantly after the engine was shut off leading to hard starts.
5.) O-Rings on the fuel delivery tube between the primary and secondary side of the carb were prone to leaking because of cracks in the rubber O-Rings.

Dave
 

live4theking

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^^^^^
From my personal experience I will agree with numbers 2 and 4.

But to be completely honest when running right I loved it. On my first 68 NYer back in 94 I drove from TX to PA and most of the time pushing 90 MPH. When I got to PA I did the math - I was getting 18MPG.

With that said I do have an AVS II sitting on the bench waiting to go on the current 68 NYer because I just cannot seem to get this one right.
 

CBODY67

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Thanks for that information. I knew the Holley 2bbls on the 440 6bbl motors were known for the ease with which they'd pop a power valve during starting. IF you knew what to listen for, you could hear the slight difference in how the engine idled after it had popped. Allegedly addressed by the anti-backfire-valve modification.

On my 4160 and 4175 which I had/have on my Camaro, the transfer tube o-rings can be a bit tricky to get right, from my own experiences. But when right, no issues. Had to be careful rolling them onto the tube so they were not abraded or cut in the process, too.

On the secondary openning issue, Holley alleges that the carb sizes itself to the engine, so a too-big carb will work on a small engine. When I put the 600cfm 4160 on my 305 Camaro, I had to get one of their spring kits to get the secondaries to open, it seemed. With the open element air cleaner, I could hear them. Took several road tests on an uphill on-ramp in "1" to get it right.

In 1968 "small town America", very few people knew about Holley carbs, much less how to work on them. They were known in the racing circles, though. Hence the term "Racing Carburetor" being applied to them, even on a production street car. This, combined with the simplicity and knowledge of Carter 4bbls by "Chrysler people", didn't help much, it seems.

I was aware of the gasket quality issues, though. It seems, though, that all of those issues have been made better with both the blue gaskets and the later "glue in place by themselves" gaskets they now use in production. Getting the bowl gaskets off is one thing, but the metering block gaskets seem to be cemented in place!

Back then, though, most dealers used the factory rebuild kits, although they were very similar to the Holley rebuild kits, with the carbs usually needing a kit each year. Not good, so they were replaced by AFBs and AVSs at the customer's request, at the local dealership. It WAS a different world back then. But when right, the Holleys did a decent job of things, by observation.

On the later Holleys I bought new, I have run them over 200K miles with none of the prior problems. Maybe a leaking accel pump diaphram, though. My '70 DH43N still has the AVS on it, though.

Just my experiences, y'alls might vary,
CBODY67
 

cbarge

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When I had my 68 NYer, I tossed the Holley in favor for a marine 750 CFM Carter carb.
I had it modified to work on the land barge.
I rebuilt the Holly twice and it never did work right.
The Carter was sweet!!
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live4theking

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On my first one when it started going bad it would backfire, subsequently popping the power valve. I'd look like a crop duster going down the road. I turned out the throttle shaft was was worn causing a vacuum leak and the problem.
 

68-NewYorker

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Start the car up and let it run for a minute or so and shut it off, remove the top of the air cleaner and look down the bores of the carb with a flash light. Do you see fuel dripping from the air horns? If so, you have a bad needle valve, bad float or the float is improperly adjusted. Remove the bowl from the carb from which ever side of the carb is leaking. Remove the float and inspect the needle valve for debris under the seat. If that is clean, shake the float to see if there is fuel inside of it. The modern blended fuels go corrosive if the vehicle is left sitting any length of time and the corrosive effects of degrading fuel eats up the lead solder in the float seams and causes them to leak. If all of the above check out ok, recheck the float height and set to factory specs. Now put it back together. There is an idle screw on the driver side front of the carb, adjust until you get about 600 RPMs. Check the choke cam to be sure it is releasing with the choke open as that can also cause too high of an idle.

Dave
Thanks Dave. To clarify, I just recently rebuilt the carb with a kit so debris and corrosion are non existent. The float inside looked brand new and there are no leaks at the current time. I don't have much time after starting it to check the choke or other adjustments before it stalls out.
 

68-NewYorker

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To add to what Dave mentioned, if the car was runnning decently well, but the carb had a fuel leak, then no real need to worry about the choke adjustments and such, UNLESS they might be causing an issue (which they usually don't as long as everything in their linkage is working as it should and is not binding-up).

Also, check to see that the choke valve is openning a bit when the engine first starts. If it remains closed, check the vacuum pull-off (on the passenger side of the carb) to see if it is working and the short length of vac hose to it from the carb metering block is not deteriorated or allowing a vacuum leak there. To verify its operation, gently remove the vac hose and manually compress the plunger with your fingers. Then use another finger to cover the end of the pull-off where the hose attaches. After compressing it, with the hole plugged/covered, release the plunger and see if the plunger moves outward. If it does, the choke pull-off probably could be one reason for the black smoke and such on cold start-up.

Get the idle speed and basic timing adjusted to specs and then do the idle mixture screws.

Please keep us advised,
CBODY67
Thanks Cbody67, I have been in the garage working on keeping it running so I can check the idle and timing. I can't keep it running enough to test the vacuum pressure. I may have had one of the vacuum lines going to the wrong place as well but it turned out that it wasn't making any difference.
 

68-NewYorker

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Your power valve gasket may not be seated on the power valve. I just had this happening to me, and I have been rebuilding Holly's for 50 years. this will allow fuel to leak /pour into the intake.
Leaky needle and seat check for fuel either dripping out of the boosters or coming out of the vents.
Did you set your float level dry only or did you set it again while running? It must be set while running.
On the needle and seats make sure you clean out the well where the needle and seat live. the new fuels will eat the O-ring and leave parts of it adhered to the wall. again happened on my last build. Take a q tip coated with carb cleaner and wipe out the bore. even a new needle and seat will leak if this happens.
Thanks for the tips. I have rebuilt the carb with a rebuild kit so there are no damaged parts on the carb that I can tell. I do agree with the O-ring issue. They leak there quite often. How do I know if a power valve gasket is not seated or is blown. Its only a year old at this point.
 

68-NewYorker

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Here's what I'm working with. It starts up with two pumps of the pedal and one or two turns. I rebuilt it last year so I wouldn't go to the extent of replacing it already. The fuel pump is only about 3 years old and the distributor, points and plugs are new.
carb1.jpg
carb2.jpg
carb4.jpg
 

413

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The sooner you get rid of that Holley for an AVS the sooner you will be happy with how it runs.

I’ve gone round and round with those Holleys and I’ve read many similar horror stories on threads like this.
 

Davea Lux

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Here's what I'm working with. It starts up with two pumps of the pedal and one or two turns. I rebuilt it last year so I wouldn't go to the extent of replacing it already. The fuel pump is only about 3 years old and the distributor, points and plugs are new. View attachment 490496 View attachment 490497 View attachment 490498

From the photo, you have the vacuum advance hose hooked to the choke pull off. That means neither of them is working. Choke pull off opens the choke so that the engine does not die from flooding. If you do not have one already, down load the FSM at www.mymopar.com it is a free down load and has a copy of the vacuum hose routing. Manual section 14-65 has the Holley service procedures. If you look on the throttle plate, on the passenger side, there is a hose port. That hose port is attached to the choke pull off diaphragm by a short hose. On the passenger side of the front metering block there should be another hose port, that port is hooked to the vacuum advance on most models.

Dave
 
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John Kirby

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Several big issues:
1.) Bowl gaskets leaked
2.) Power valves or power valve gasket blew out if the engine farted back thru the carb, common on all big blocks.
3.) The velocity port for the vacuum secondaries was poorly located and often would not open the secondaries until about 3500+ RPMs, buy then the pass on the open highway was done.
4.) Carbs on a warm engine boiled over constantly after the engine was shut off leading to hard starts.
5.) O-Rings on the fuel delivery tube between the primary and secondary side of the carb were prone to leaking because of cracks in the rubber O-Rings.

Dave
#2 is an indication you need an engine rebuild. My 66 used to do that all the time. A rebuild with a double roller timing chain, new cam and a valve job WITH new bronze valve guides fixed it. Hasn't backfired since. Also gets up and goes like it never has before. Wasn't cheap though.
 
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