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Registered
Join Date: Jul 2003
Location: Australia
Posts: 11
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PPI Compression/Leakdown Results
Hi all,
My brother just received the results from a PPI done on a 82 SC here in Oz. Results as follows 175 - 4% 185 - 14% 50 - 2% 180 - 8% 175 - 6% 175 - 6% With the exception of #3 cylinder, the figures look OK to us. Are they good results? My other question is.... What could be causing the problem with the #3 cylinder. To me the figures contradict somewhat since leakdown is only 2%. Any help would be greatly appreciated. Cheers X... |
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07-16-2003, 08:22 PM
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Join Date: May 2002
Location: Portland, Oregon
Posts: 12,669
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No expet but may be a bit of carbon under the valve.
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Harry 1970 VW Sunroof Bus - "The Magic Bus" 1971 Jaguar XKE 2+2 V12 Coupe - {insert name here} 1973.5 911T Targa - "Smokey" 2020 MB E350 4Matic |
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07-16-2003, 09:33 PM
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Binge User
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Would water injection clean the valve?
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Paul |
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07-16-2003, 09:37 PM
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Not Quite Banned
Join Date: Dec 1999
Location: Ft. Lauderdale
Posts: 1,223
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It is almost like something happened between tests on #3. The compression # is low, so there could have been something holding a valve open. The leak down looks good, so whatever it was that affected the compression # had disappeared at that point. I would run the tests again, perhaps with a different shop, if you are interested in the car.
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Thomas Owen 1972 911T 1972 911S |
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07-17-2003, 05:40 AM
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Friend of Warren
Join Date: Oct 2000
Location: Lincoln, NE
Posts: 16,500
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My guess on #3 would be misadjusted valve or a piece of carbon got stuck under the valve. Hard to believe only one cylinder would be reading that low without problems in the other cylinders.
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Kurt V No more Porsches, but a revolving number of motorcycles. |
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07-17-2003, 06:53 AM
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Senior Member
Join Date: Nov 2000
Location: Great NorthWest
Posts: 3,950
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Is this car a garage queen? If so, best to perform these tests after a week or so of good hard driving.
A valve adjustment may be in order. Carbon under the valve may be the case - if so a retest is needed. Stuck ring(s)? Regardless, it is a negotiating point. John
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'78 Targa in Minerva Blue |
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07-17-2003, 07:38 AM
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Join Date: Dec 1999
Location: TX USA
Posts: 9,804
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If the car has been sitting up for months - years, then carbon falling loose from intake valve or combustion chamber is the most likely problem.
Do a search on "chemtool carbon procedure" to get one method to clear the carbon and restore compression ...
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Warren Hall, Jr. 1973 911S Targa ... 'Annie' 1968 340S Barracuda ... 'Rolling Thunder' |
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07-17-2003, 04:47 PM
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Location: Australia
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Thanks for the help guys.
Info has been passed onto the current owner who is willing to fix it regardless of cost. Should be in our driveway within a fortnight. Being the first Porsche in the family, we're both walking around with smiles from ear to ear! Cheers 
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07-18-2003, 02:36 AM
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Not Quite Banned
Join Date: Dec 1999
Location: Ft. Lauderdale
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Good luck - please pass along the results of the repairs.
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Thomas Owen 1972 911T 1972 911S |
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07-18-2003, 05:40 AM
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Member
Join Date: Mar 2002
Location: Bellevue, WA
Posts: 58
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I don't understand all the posts that suggest the low compression may be caused by carbon under a valve. This would also result in high leakdown.
I agree with Tom Owen. I don't see how you can have such poor compression and such good leakdown. Something's odd.
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Bob Spindel '73 911 w 2.7S engine |
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07-18-2003, 11:16 AM
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Join Date: Jan 2003
Location: SF Bay Area
Posts: 125
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Doesn't #2 look a little odd also, with the highest compression, and the highest leakdown?
...Bruce |
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07-18-2003, 03:23 PM
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Location: Australia
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Just an update gents.
The car has gone on a spirited drive. Upon return, it was re-tested at the current owners workshop where the resultss came back good. We confirmed the results with our workshop. We pick the car up this coming Tuesday. Sweeeet!!! Thanks for all the help everyone. We'll post some piccies next week. Cheers 
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07-25-2003, 09:54 PM
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Join Date: Jun 2002
Posts: 60
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Congrats! ( and welcome to the SC kingdom).
You'll come to realize that there isn't any other site that can compare to this one. It's chock full of great guys, gals, cars and info. Regards, Gary
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'79 sc Targa |
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07-25-2003, 10:13 PM
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Join Date: Jan 2003
Location: San Francisco
Posts: 377
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What's the compression you'd want to see on an 84 Carrera with 180,000 miles? I think my 3's read between 155-135. Good? bad?
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1984 Carrera Coupe |
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07-25-2003, 10:38 PM
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Location: Sydney, NSW, Australia
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xblode, whereabouts in Australia are you?
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2004 VW R32 - B road bahnstormer 1992 Peugeot 205 - Tarmac rally weapon (well eventually...) |
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07-26-2003, 09:41 PM
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Location: Australia
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Sunny Melbourne!
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07-27-2003, 01:42 AM
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Not Quite Banned
Join Date: Dec 1999
Location: Ft. Lauderdale
Posts: 1,223
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Glad to hear this worked out for you.
Good luck,
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Thomas Owen 1972 911T 1972 911S |
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07-27-2003, 06:08 AM
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Schatzi
Schatzi
