Leak down test

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06-16-2003, 02:30 PM

Randal

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Leak down test

HI
I just did a leak test on my 964, the numbers are
1.(8%) 2.(9%) 3.(6%) 4.(8%) 5.(8%) 6.(6%)

this was done just warm, did another cold and the numbers almost doubled.
the car has very good power and runs and idles very smooth

so what can I tell from these numbers??
Randal

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06-16-2003, 05:24 PM

J-McDonald

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It sounds like your engine is very healthy. The numbers should be close to each other (which they are), and the acceptable range is 5-15% (which all of them are within).

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06-16-2003, 08:18 PM

Martin Hodgkiss

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How do I do a leak test?

Sorry for my ignorance!!

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06-16-2003, 09:53 PM

Kevin

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Martin;
Basically you are trying to pressurize your cylinders at TDC with air. As the air leaks out, a percentage is given of leakdown. The air will leak past your rings, valves and so forth. Snap On makes a nice gauge.

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06-17-2003, 09:13 AM

robmug

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Snap On tool:

<a href="http://buy.snapon.com/catalog/main_xml.asp" target="_blank">Snap On UK site catalogue</a> - choose Diagnostic, then "Cylinder Leakage/Engine Vacuum/Fuel Pump Gauges And Tester" (The URL is too long for the script to work on this forum). £169 + vat.

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06-18-2003, 12:44 PM

Randal

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Rob

Will this tool also do a compression test?

Randal

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06-18-2003, 01:16 PM

robmug

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<blockquote>quote:<hr />Originally posted by Randal:
Rob

Will this tool also do a compression test?

Randal<hr /></blockquote>No - but they also do a compression test tool for £118 ($198).

BTW, I'm just working on Kevin's comment that "Snap On makes a nice gauge"

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06-19-2003, 06:10 AM

johnfm

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You'll need a source of compressed air as well as the gauge, BTW.

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06-19-2003, 07:25 AM

Roygarth

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<blockquote>quote:<hr />Originally posted by johnfm:
You'll need a source of compressed air as well as the gauge, BTW.<hr /></blockquote>Baked beans for tea? <img border="0" alt="[hiha]" title="" src="graemlins/roflmao.gif" />

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06-19-2003, 07:48 AM

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Christer

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oh christ, you really don't deserve that RS Piers!

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06-19-2003, 08:52 AM

#11

robmug

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<blockquote>quote:<hr />Originally posted by johnfm:
You'll need a source of compressed air as well as the gauge, BTW.<hr /></blockquote>Good point! I thought that the cylinder/piston would develop the compression...

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06-19-2003, 10:19 AM

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Roygarth

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<blockquote>quote:<hr />Originally posted by Christer:
oh christ, you really don't deserve that RS Piers!

<hr /></blockquote>Apparently not...just been told that delivery next week is unlikely!

Piers

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06-19-2003, 10:41 AM

#13

johnfm

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Rob

compression test measures compression from the piston inside the cylinder. Leakdown measures how well the cylkinder/head/piston rings can maintain pressure.

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06-19-2003, 10:51 AM

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Christer

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<blockquote>quote:<hr />Originally posted by Roygarth:
 <blockquote>quote:<hr />Originally posted by Christer:
oh christ, you really don't deserve that RS Piers!

<hr /></blockquote>Apparently not...just been told that delivery next week is unlikely!

Piers<hr /></blockquote>They must read your jokes on this forum.....

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06-19-2003, 11:07 AM

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robmug

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<blockquote>quote:<hr />Originally posted by johnfm:
Rob

compression test measures compression from the piston inside the cylinder. Leakdown measures how well the cylkinder/head/piston rings can maintain pressure.<hr /></blockquote>Thanks John

Got it...I can see now how they are different. Doh! (One of my key strengths is knowing what I don't know)

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