fog machine vac leak test?

[Bri7man]

I want a relatively cheap fool proof way to find any vac leaks in my system. I sprayed soapy water all around my vac lines while my engine was running and found no bubbling, but for some reason it just doesn't strike me as a very reliable or fool proof test method and neither does the blowtorch fuel method..

Anyways, there are actual smoke testers out there for this sort of thing, but they are pretty darn pricey, so I was thinking of this:http://www.partycity.com/product/fog+machine+400+with+remote.do?sortby=ourPicks&size=all&from=Search&navSet=fog+machine

I was wondering if this machine would harm my engine in any way, would condensation build up and possibly cause hydrolock?

 

[jonahs_supra]

spraying soapy water on your engine wont show vaccum leaks
vaccum is suction, so maybe the water would be sucked in through the line lol

i wouldnt recommend using the fog machine
at work we use a OTC evap smoke machine...works pretty good but doesnt show the small leaks

best way i found to check for vaccum leaks
use a shop air blow gun
http://www.mytoolstore.com/astro/astmat08.html
remove vaccum line from charcoal canister...the one that runs to t stat housing(IIRC it has something to do with the VSV system)
next slide line onto end of gun
apply small amount of pressure into line...if you got a mechanical boost gauge then build enough pressure to where your boost is set at(i normally do 2psi over)
now listen for leaks or spray vaccum lines and connections with soapy water
if theres a leak then it will bubble

 

[Bri7man]

Ahh very nice, thank you! That was a derp move on my part..

 

[jonahs_supra]

Lol no problem
You'll probably be shocked at all the small leaks you'll find
I just put zip ties on the small lines to help seal

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[Bri7man]

Yeah I'm pretty sure that's my problem, I want to test my whole system so I think I'm going to to test at the accordion hose where the afm housing plugs into.

Apparently it's fine to do this and push 20psi through your engine to really find and secure ALL the loose fittings?

 

[jonahs_supra]

I wouldn't pressurize using the accordian hose
The pcv system will pressurize and may cause a crank seal to push out

Best thing to do is make a boost leak tester for your intercooler

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[bioskyline]

pressuring the sstem thru the accordian wont affect the block to much, as it pressuizes the intake and cyls, all u will get is normal blow by depending on condition of the rings, so 20 psi topside might equal 3-5 psi bottom side, nothing that a non moving motor can take

 

[jonahs_supra]

How are the pressures between top and bottom different when applying pressure through accordian?

From my understanding it will pressurize pcv hoses
Then it will pressurize the compete motor (internals)
With 20psi of pressure in the motor that may or may not be enough to roll the crank seal
But I could be wrong

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