Holley 4160 P/N 1850 (Single feed/ Vac. Sec./ Mech Choke). Dipped and rebuilt with every new gasket and seal known to Holley. The Secondaries still don't work. The vacuum line from the primary venturi to the secondary vacuum diaphram is clear of debris and sealed at the body where the diaphram housing bolts to the main body of the carb. I've meticulously gone over the secondary (Metering Plate?) to make sure everything is clean and making good seal. I've rebuilt one other Holley (4150 P/N 4777 Dual Feed/ Double Pump/ Mech Sec./ Mech Choke) with the same attention to detail and it has worked like new for at least 50,000 miles.

Does Anyone know of some off the wall problem these carbs (4160-1850) have had. My 352cid runs without a hitch on just two of the four barrels workin' but it bugs me that the secondaries don't work after making sure everything was right when rebuilt.


Fire Away, I'm open to anything

Jim

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66 Mustang Coupe
66 F-250

 

How do you know they aren't working?

 

did you make sure you opened the primaries before attempring to force open the secondaries?? ( assuming you noticed this with the carb off or are trying to open the secondaries by hand).
if you suspect they arent opening while your driving, thats kinda hard to know sometimes..........usually you have to really makin some rpm for them to open all the way...........
there is a way you can make it so the secondaries manually pop open a little to see weather or not you need or want them open or not. this involves putting a small nut and bolt in the linkage on the driver side.........it's not hard to do but kinda detailed to explain so i'll wait to see if that is indeed your problem or not.........

 

You will probably never get them to open while sitting still, and if they do, it will bog terribly when driven.

Which spring do you have in them?

Try putting a wire tie around the secondary actuator rod (it has to be tight enough to not fall, but lose enough not to bind them) and drive the truck. Then take a look at the wire tie to see how far they are opening.

 

I would just tie them shut and drive it. If you loose a lot of top end power then you know they were working.

 

Unfortunatley the the truck isn't road worthy yet, I'm waiting for rims and tires.
Since this is my first Vacuum Secondary carb I assumed the secondaries would open if I stabbed the throttle at different RPM's while I was fine tuning the motor. Other than that, mechanical everthing is working, nothing binding or anything like that. When I hold the primaries open a little and manually open the secondaries, the motor revs like everything in the secondaries is workin.
LuvFordTurucks, I know what you're talking about with the nut and bolt, my old man told me about how he use to do that before he got a mechanical sec. carb. Luckily there's an aluminum intake on the 352, but I've picked up the origional cast iron 2bbl intake to move it around the garage, needless to say, it'll never find its way back on that motor.
DuckRyder, It has the lightest spring available, according to my Dad. I see what you're sayin' about the tie wire and I'll try it when I get it on the road.
Ratsmoker, in the same respect I'll try that too.

Thanx alot guys, I'll stop gunning the motor to see if the secondaries open. What if I held the throttle open a bit and cover the choke stack with my hand? Will that coax the secondaries into open, or will it just suck a bowl full of fuel from the primary?

Jim

 

The engine will just die. You might get a nice hickey though!

 

Hell, I might just do it for the hickey! Maybe I should asked if there was anyway to coax the secondaries into opening while the truck is just sitting there.

Jim

 

Not safely. The engine must be under full load. Theres only one way to do that and that is by power braking it. Then it would not be a good idea to be crawling around under the hood. You can just imagine the possible consequences.

 

What if I tied it to a tree?, Naw it'd pull the tree outta the ground.. Oh, well. I'll tell you guys how its goin when I get it on the road in a week or two. Thanx for all your help and humor Ratsmoker.


Jim

 

Anytime