Holley 4160 leak

[Randy S.]

Re 66 327 300HP Holley 4160

Gents,

The other day I noticed a pool of fuel on my intake manifold under the crankcase ventilation connection ( right rear) I assumed this was a leaking rear fuel bowl gasket. I went to my local flaps and got the Holley blue fuel bowl gaskets 108-92-2 and metering plate gaskets ( 108-89-2)

Now that I look at section 6M-47 of my Overhaul manual I see the 4160 has a different front and rear metering body. Is there a gasket for the secondary metering body? Looks like the bowl gaskets are correct but I will only need one metering plate gasket for the front. Correct or did I get the wrong gasket set.

BTW I have run the car again and I do not see any fuel leaking from the bottom of the float bowl.

Can the fuel bowl gaskets be installed with carb on car? I am apprehensive about damaging the threads on the fuel inlet and would rather not remove carb from car

[Randy S.]

Re: Holley 4160 leak

Update;

It is still leaking at the right rear. I was hoping to see the leak while it was idling but the fuel shows up a few hours after shutdown.

Also trying to determine the correct blue non stick gaskets
looks like for primary the fuel bowl is 108-92-2 and the metering block is 108-89-2. On the secondary side looks like only one gasket for bowl and metering plate 108-90-2

[Frank E.]

Re: Holley 4160 leak

Re 66 327 300HP Holley 4160

Gents,

The other day I noticed a pool of fuel on my intake manifold under the crankcase ventilation connection ( right rear) I assumed this was a leaking rear fuel bowl gasket. I went to my local flaps and got the Holley blue fuel bowl gaskets 108-92-2 and metering plate gaskets ( 108-89-2)

Now that I look at section 6M-47 of my Overhaul manual I see the 4160 has a different front and rear metering body. Is there a gasket for the secondary metering body? Looks like the bowl gaskets are correct but I will only need one metering plate gasket for the front. Correct or did I get the wrong gasket set.

BTW I have run the car again and I do not see any fuel leaking from the bottom of the float bowl.

Can the fuel bowl gaskets be installed with carb on car? I am apprehensive about damaging the threads on the fuel inlet and would rather not remove carb from car

The 4160 secondary metering plate is internal to the fuel bowl. It's attached to the main body with a gasket and clutch head screws. The bowl gaskets you have may work but you need to supply your flaps with the "List number" of the carb. BTW, for that engine, it should be a list 3367.

To answer your questions, the fuel bowl and all metering gaskets can be changed on the car but it's a lot easier to just remove the carb. I understand your concerns about the inlet, but at some point you'll need to address it and why not now? When you assemble the bowls with the new gaskets, be careful not to over torque the bowl screws.

Hope this helps.....

[Bill M.]

Re: Holley 4160 leak

i allways leave the carburator loose on the intake studs when instaling the fuel line. gives me plenty of play to get that bugger started.

[Randy S.]

Re: Holley 4160 leak

Re 4160 List 3367 Holley
Upon further inspection I noticed it is not leaking from the rear fuel bowl gasket but gas is dripping down from the secondary throttle operating assembly, dripping from the actuating rod. I am just going out the door to do some errands so I will stop by a FLAPS to see if there is gasket kit for this actuator

[Gerard F.]

Re: Holley 4160 leak

Randy,

If it is only leaking slowly after you shutdown, that could be coming from the gasket between the main body and the throttle plate assembly.

There are tracks in the top of the throttle plate between the primary side and the secondary side which feed fuel for the secondary idle. If the gasket between main body and throttle plate is dried out or the plate or main body is warped you will get a leak from between the main body and the throttle plate.

I have found that when my 67 (w/Holley 3810 similar to 3367) sits for a long time, the gasket seems to dry out and I get a leak after the first startup.
After I take a long run and get things heated up, the problem goes away.

If your car sits for a long time (2-3 weeks) without start up, you might just try taking a long run and get things heated up, then tighten the carb to manifold nuts and fuel bowl screws.
See if that works. It may save you a lot of time, rather than taking the carb apart. Then start the car up every week, and heat it up.

[Timothy B.]

Re: Holley 4160 leak

Randy,

I second what Jerry said, check the throttle body (base) gasket.

There are also two unused screw holes in the Holley base and you can tap and install those screws if you can find some donors from another Holley. On the 300hp cast iron manifold there is no chance they can come loose and fall into the engine.

On the aluminum manifold they can fall into the engine if they come loose that's why they are not used in production but on aftermarket Holley's I believe they are used.

[Gerard F.]

Re: Holley 4160 leak

Randy,

If you have to change the gasket between main body and the throttle body, it is advisable, as Tim says, to tap and put screws in the two unused screw holes.

Here's a post from the archives, that shows how to do it:
https://www.forums.ncrs.org/showthre...olley+throttle

Take a look at the pictures in the thread. The position of those two unused screw holes is right adjacent to the secondary idle feed track in the throttle base which runs along the edge of gasket. The extra screws help seal that track from leakage and help in preventing warping of the throttle base.

I think you will see the impression of the secondary idle feed tracks in the photos and how close they are to the edge. The fuel in those tracks comes from the primary bowl through the primary metering block. When you adjust the idle mixture screws on the sides of the metering block, you are adjusting the amount of fuel going into those tracks to the secondary idle.

[Randy S.]

Re: Holley 4160 leak

Thanks to all who responded.
I pulled the carb and dropped it of at local carb rebuilder. I suspected a secondary shaft leak and he quickly checked it and thinks that is where it is leaking. He showed me the plastic (nylon?) sleeve that seals the secondary shaft. While carb is off I will finally plug the hot slot.

Randy