1956 Holley 4000 “ the firebox” carburetor

[knuckle47]

I have just started a rebuild on my Holley 4000. Prior to diving into this I tried to read as much as possible on this carb. Frankly, with having read so many comments about its complexity…I was a bit apprehensive but it is a fairly straightforward assembly SO FAR.

Anyhow, I found a few references to this carb being known as the “firebox” carb due to the many fires it started from leaking fuel. Now for the story: I had wanted a T-Bird for decades as my mom and dad had one in the early 60’s when I was a kid and was sold eventually to buy a house. It just dawned on me. My mom told me back in the mid 60’s that the car had caught fire from the carb …light bulb moment for me 58 years later

Has anyone here had fire issues that relate to this being branded the “firebox” carburetor?

This page contains affiliate links for which I may be compensated. As an eBay Partner, and Amazon Associate I may be compensated if you make a purchase at no cost to you.

 

[74 Harley]

I am not aware of that title. However that's just me. I understand that they are a little more complicated, but not rocket science.

 

[biddle]

If you research, fires from carburetors are usually from ones that have leaks from the screws etc. See below.

 

[jack-in-sac]

If you research, fires from carburetors are usually from ones that have leaks from the screws etc. See below.

View attachment 20433

What are those torque specs? Thank you, J.

 

[Pete986]

‘’Firebox’’
Where’d you hear THAT one?

 

[Ward 57]

Well being a shade tree mechanic, I've relied on the 'finger tight' Sinch it down until you feel it 'click' or get firm resistance. Then as above, work it a few cycles and then cinch down again.
This assuming you ran a fine file over the body and fuel bowl faces. It's not uncommon for them to warp slightly.

 

[74 Harley]

The only time I have had a Holley leak was a bad accelerator pump.

 

[Ward 57]

The only time I have had a Holley leak was a bad accelerator pump.

Yah, that's why I had mine rebuilt. I figured if that diaphragm cracked the other seals are not behind.

 

[knuckle47]

I read this at 3 different web sites and one of them was Mikes Carb…as I looked in so many places to learn all I could about this rebuild…his seems to be quite authoritative and he was the 3rd time I’d read it. Then, while the synapses in my brain started to re-connect…BAM…the visual of mom telling me about that car over 50 years ago came to light.

Since it seemed like it could be a more common occurrence than not, I was curious if anyone here had some experience with this. I do see a lot of fire extinguishers in so many t-bird photos. Especially since this is a rather high concentration of 1950’s Thunderbirds

As far as my rebuild, I only have it torn apart and labeled on a big spread of brown paper with circles and arrows ( Alice’s Restaurant style) highlighting each section . Tomorrow should be a soaking and cleaning day. I am thinking of gently flat filing the base point of contact at the manifold gasket

 

[paul5456]

As far as making sure the mating surfaces are flat, use a piece of flat glass or metal with sandpaper on it and run the surfaces over the sandpaper.

By the way, the other nickname for the 4000 is Towering Inferno

In my opinion, the 4000 is a very good carb if rebuilt correctly. I have one on my 56 that has survived two trips from coast to coast as well as a lot of local and other long distance driving with no problems. I had it professionally rebuilt by a known expert on these particular carbs.

 

[74 Harley]

Check it with a square before you file. It may not be necessary. And then I really wouldn't use a file at all.
Try this instead. You will need a flat wood surface. Staple down a piece of 220 grit that is 12"x12". Assemble carb body only to base. No gaskets. Using the body as a handle you can lightly sand the base flat. It takes very little pressure.

 

[knuckle47]

That is EXACTLY my plan. Since there are 3 sections to it, I can easily check the surface for square while disassembled and slide it across a fine grit paper.

Well, I did find the “towering inferno” references on two separate web sites… ford barn and jalopy journal … YIKES!