Smoke machine for finding leaks?

[slipnfall]

Hi folks, A buddy of mine who's in auto repair told me they have a, for lack of better terms, smoke machine at their shop. Basically it creates a dense smoke that is used in finding vacuum leaks, etc. I guess you let a vac line suck it in and look where it escapes. I'm wondering if they make any type of kit like this for home/shadetree mechanic's use. Maybe something that has smoke 'pellets', or whatever dropped into a sealed canister, possibly disposable? It sounded like the machine they had was expensive. I thought maybe I could rig something like this up w/some smoke bombs , but I would imagine it'd take a good quantity of smoke to seep out any cracks(as vacuum would keep it in, and engine operation may 'use up' some of it).

This just seemed like a much thorough test for leaks over the carb cleaner hit-or-miss method.

Thanks,-Slip

[DAEDALUS]

I don't think you use it with the engine running. The vacuum, as you pointed out, would make it impossible for the smoke to get out. My tool supplier sells a machine for $700. Can't be too complicated. Figure out what makes it smoke, and then just buy the fluid and replicate it shadetree. This might give some clues:http://www.smokemachines.net/faqs.shtml

If heat make it smoke, use a sealed metal can with a brass fitting that's piped to one of the vacuum ports. Heat it up with a heat gun. Just a thought, hope that stuff isn't poisonous!

[navysnail]

i wouldnt use a smokebomb because those create a tar like substance.

[NISTECH]

The smoke machines are awesome , fairly new to the market, I have used one several times, depending on what kinda machine you use has different abilities althoung the machines I have used where anywhere from $2k to $5k The last one had a blacklight set up. What they do is heat a special kind of oil that is pumped into the vehicle while it is off, where ever your leak is the smoke will come seaping out after a couple seconds, The machines I used also tested for leaks as it had a calibrated loss meter it could tell if your leak was .020 or .040 diameter hole [meaning small leak or gross leak] by the amount of loss it took once it built pressure, this was used for EVAP system leaks.

[slipnfall]

Sweet info, thanks guys! And yeah, I don't think tar in the engine would be a good thing. :-0 I have some good ideas pumping(no punn intended?) through me now. This would make a nice DIY home-made writeup. Too bad I don't have some money to trash at the moment.

You could easily wire up a sealed adjustable heater with a resovour supplying it. A small portable air compressor would be primo(even good fish tank pump might suffice), in/out pressure regulator and gauge. As long as you kept everything sealed up really well it would be good enough for home use.

To those that have used them, do you know the typical PSI/CFM range these pumps operate at?

Thanks!-Jamie

[NISTECH]

less then 1psi

[NISTECH]

I have used 2 different set ups one used shop air supply and regulated it down to the low pressure and have used an electric pump style.

of course you could open your throttle plate and set a small chunk of dry ice in there,close the plate and wait to see where the smoke comes out too??

[slipnfall]

haha, yeah that would work I suppose, I could just run down to Harry's General and pick up a chunk. </smartass>

I'm glad to hear it's not high pressure. I found a couple sites on home-made theatre fog machines, and I'm sure it's the same principal. It seems that a lot of the 'visual arts' fog machines use a glycol-based solution, which IIRC, is a main ingredient in soap, right?(glycol+lye?). Don't think I'd want a sudsy mist in my engine, so I'll have to look into the real smoke machine refills.

-Slip

[NISTECH]

lol you know more than I do then, I thought they used dry ice,hence my suggestion.

[slipnfall]

no prob, you've def. helped. Otherwise I'd be pumping 150psi into my engine. :-)