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FPH Gruppe
Join Date: Aug 2002
Location: Way up the left coast and inland a bit
Posts: 1,797
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Leak down results, I was afraid of this!
I got the use of a leak down tool and here is what I found:
#1 20% #2 6% #3 8% #4 7% #5 6% #6 7% I knew something was up with #1, when I pull the plugs its always much darker than the rest... the car runs pretty well, a little bit of a miss at lower RPMs, but it seems to pull to redline happily. This is my first 911 so I don't have anything to compare it to... The instructions with the tool say to perform the test on a cold engine due to dangers of injecting cold air into a hot engine (seems like when one is running at high RPMs that would be going on quite a bit anyway), Wayne's engine rebuild book says to perform the test with the engine warm. Do you think I should check it warm too, is there really a risk???
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Skip Newsom 72 911T Targa Signal Yellow Now sporting a big Port 3.0 built by THE John Walker |
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12-29-2003, 07:19 AM
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Friend of Warren
Join Date: Oct 2000
Location: Lincoln, NE
Posts: 16,492
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I've always done my checks with the engine warm. I would recheck it warm. I would also do a compression test while you are at it. Also with the engine warm.
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Kurt V No more Porsches, but a revolving number of motorcycles. |
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12-29-2003, 07:21 AM
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Registered
Join Date: Jul 2002
Location: Atlanta
Posts: 7,125
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I have a similar thing going on for a year. I try not to think about it. Runs great? I figure if I really tare it up before I get a chance to fix it 3.0 core motors are getting cheap enough to justify my laziness/cheap ness.
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erik.lombard@gmail.com 1994 Lotus Esprit S4 - interesting! 84 lime green back date (LWB 911R) SOLD  RSR look hot rod, based on 75' SOLD 73 911t 3.0SC Hot rod Gulf Blue - Sold. |
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12-29-2003, 07:28 AM
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Irrationally exuberant
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A leakdown test is not a definative test - good engines can have bad leakdowns and vice versa. You use it with other tests to get a true picture of what is going on. I would listen to find where the leaking air is going - out the valves or past the rings.
-Chris
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'80 911 Nogaro blue Phoenix! '07 BMW 328i 245K miles! http://members.rennlist.org/messinwith911s/ |
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12-29-2003, 07:29 AM
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Registered
Join Date: Mar 2001
Posts: 1,031
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Test with a warm engine, not hot, but warm. Injecting cold air, especially 'wet' air from a compressor without a dryer installed, wont do the exhaust valve any good..
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12-29-2003, 07:34 AM
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FPH Gruppe
Join Date: Aug 2002
Location: Way up the left coast and inland a bit
Posts: 1,797
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Thanks for the replies!!
I bought a Gunson Gastester a few weeks ago that I've wanted to use too, so looks like I have my projects for the day set! It's clear, nearly dry and about 29 degrees in the Pacific Northwest this morning, looks like I get to go for a "warm up" drive... excellent! I'll set the CO levels at 3K and idle, do a compression test, and leakdown while warm. I'll post the results...
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Skip Newsom 72 911T Targa Signal Yellow Now sporting a big Port 3.0 built by THE John Walker |
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12-29-2003, 08:32 AM
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Gon fix it with me hammer
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heat expands components, so you might get a better result on #1 once things have warmed up
if it runs good, i wouldn't worry to much about it, it's not like all cyllinders have 20% or more.... if you average your's , you have 9% which is not bad according to the book 
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Stijn Vandamme EX911STARGA73EX92477EX94484EX944S8890MPHPINBALLMACHINEAKAEX987C2007 BIMDIESELBMW116D2019 |
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12-29-2003, 09:03 AM
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The Blue Pheonix
BimForce the Third, Esquire
