Adjusting air intake of non-adjustable burners

[enimalx]

Hello forum,

I bought a universal BBQ burner to replace my old rusted out one. While the heat is very even now, the color of the flame leaves a lot to be desired. This is what it looks like on high:

dHXr0O7.jpg

• enimalx
• Jun 29, 2015

On low, the flame looks almost perfect, which makes me think that there is not enough air getting mixed with the gas. It turns out that the air intake cannot be adjusted on this, so in hope of increasing the air intake I cut out the grill on the air intake and tried drilling some holes.

urZHdIg.jpg

• enimalx
• Jun 29, 2015

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• enimalx
• Jun 29, 2015

The result was only marginally better. You can see it a little on the first image. Top flame is with stock air intake, bottom with my modifications.

Also after cutting the first hole, the titanium drill bit became completely dull, which explains why the second hole is still unfinished. I'm gonna have to file the drill bit now, but... before I waste more of my time drilling into some relatively thick stainless steel, could I just punch some holes into the aluminum tubing? Image of the whole burner below:

azchxfz.jpg

• enimalx
• Jun 29, 2015

Or would that be a very bad idea? My gut feeling is telling me that the gas might leak out from those holes, but then why doesn't it leak out at the air intake holes? I don't really understand how those venturi tubes work so clarification is also welcome.

 

[boboso]

My dad had a similar problem a few years ago. He just covered the burner with lava rocks. Last year, he bought a brand new grill. Wish I could help, but gas grills and me don't get along too well.

 

[JckDanls 07]

does that burner match the PSI's the regulator puts out ??

Also.. when drilling SS you need to drill as slow speed as possible with plenty of cutting fluid... heat builds up quick and destroys drill bits ...

 

[daveomak]

The flammable gas is injected and sucks in the free air... then it mixes and burns at the burner.... The orifice and air inlets and burner holes are all dependent/sized on each other for a good, clean burn...

Propane Venturi.png

• daveomak
• Jul 1, 2015

 

[enimalx]

JackDanIs, I wish I'd known your advice before I started drilling. The first hole took a whole 5 mins to drill through. Spent 10 mins on the second hole, and you know the rest of the story... I've drilled before though, so I knew about the vegetable oil trick. Didn't know at all about the drilling speed, pressure, or how dull the drill bit was, haha! So much for titanium drill bits, when well sharpened HSS drill bits drill just as well...

Anyhow, I'm really satisfied how well it's turning out. Here's a couple pictures to compare:

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• enimalx
• Jul 3, 2015

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• enimalx
• Jul 3, 2015

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• enimalx
• Jul 3, 2015

 

The fire burns much leaner now. Still nowhere enough oxygen though ... Especially after all the drilling and snipping it went through:

IMG_0470.JPG

• enimalx
• Jul 3, 2015

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• enimalx
• Jul 3, 2015

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• enimalx
• Jul 3, 2015

I must say that I was really paranoid when I finished drilling 8 small holes... Scared me to death when I noticed an unfamiliar high pitched noise coming from the air intakes. When I finally grew the balls to take my lighter to the air intake, boy was I amazed when it sucked up the flame. Even now I am still amazed it's sucking it up with the current setup. When I tried it with the knob on low though, there was actually a small flame, indicating that there was a small leak. After some testing and 20 mins of grilling kebabs on a low flame, I can confidently say I'm no longer afraid of the leak.

Here's to hoping that some more snipping will bring the fuel/air mixture to that sweet blue with yellow top....