Intake leak test question

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Intake leak test question


Post by txpan49 » Sat Apr 29, 2006 5:34 am

I am using Cotten's Virtual Indian intake leak test method and have some questions. My available tools include a rubber bathtub stopper and an air compressor hose with the air compressor set on 15 lbs. I put the stopper in the intake and insert the compressor hose in a hole I put in the stopper. The stopper fits pretty snug (like it would in a bath drain) and I squeeze the air trigger. The plug pops out pretty rigirously. I made a retainer to hold the plug in while I get the full air stream going and it will not stay in place and I see no bubbles from my flanges.
If the air intake can pressure up enough to blow this kind of stopper out continously do you think I have a good leak test?

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Re: Intake leak test question


Post by Jack_Hester » Sat Apr 29, 2006 8:22 pm

Back off to about 10 or 12 psi, and try again. Leak bubbles will show up at a lower pressure, too. You need to be able to watch it for a bit.


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Re: Intake leak test question


Post by mbskeam » Sat Apr 29, 2006 11:16 pm

try a hose clamp or 2, around the whole stopper and manifold.....
but A.C. gages at 15psi are very inaccurate at low readings


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Re: Intake leak test question


Post by Cotten » Sun Apr 30, 2006 4:48 pm

15 psi is actually overkill.
14.7 is equivalent to total vacuum at sealevel, and I doubt that vacuum ever approaches two/thirds of that.
But overkill is nice when you are doing a diagnostic.

The important thing is that the supply is constant. Airbottles and handpumps don't cut it.

I find soft rubber stoppers (common laboratory #9 for an OHV, I think)will stay in at 10-12 psi, and letting the system sit under pressure for a minute or two is important to discern the very tiniest leaks, which manifest themselves as little zits or even hanging tits of foam.
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