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Cracked 964 Cylinder Head
Getting ready for a race weekend next month -- was ready to button things up.
Engine was running great but I wanted to get a baseline.  Well #6 doesn't look quite right -- valves were just adjusted and double checked and they looked good. Smoke test showed exhaust valve guilty. Oil drained out of exhaust valve as well when inserted into cylinder. Pulled headers .... found the culprit.  Not sure if this is fixable -- or time to source an alternate. mike
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2015 Panamera Hybrid, 2008 Cayenne Twin Turbo 2001 996 GT2 1999 Spec Boxster, 1996 993 Cabriolet 1992 964 Cabirolet, 1975 911 RSR Replica Race Car |
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05-25-2016, 05:20 PM
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Join Date: Feb 2007
Location: Northeast
Posts: 464
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Weird. The crack would have tp be all the way into the valve seat to create comp. loss.
I'm thinking not likely repairable but obviously a teardown is in order-sorry.
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Mark www.exotechpower.com 1981 Targa-messed with. 91 C2 supercharged track rat Radical Prosport-irritates the GT3 guys 40 years of rebuilding services |
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05-26-2016, 02:10 AM
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Join Date: Feb 2006
Location: Ontario Canada
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yeah im thinking that is not the issue in the pic , but definitely there has ben a compromise and there could be another crack further up .
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1976 Yamaha XS360 ( Beats Walkin') 1978 911 SC Targa ( Yamaha Support Vehicle ) 2006 Audi A4 2.0T (Porsche Support Vehicle ) 2014 Audi A4 2.0T Technik (Audi Support Vehicle) |
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05-26-2016, 06:13 AM
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Member 911 Anonymous
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Have you tried using a BoreScope?
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'85 Carrera Targa Factory Marble Grey/Black * Turbo Tail * 930 Steering Wheel* Sport Seats * 17" Fuchs (r) * 3.4 * 964 Cams * 915 * LSD * Factory SS * Turbo Tie Rods * Bilsteins * Euro Pre-Muff * SW Chip on 4K DME * NGK * Sienes GSK * Targa Body Brace PCA/POC |
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05-26-2016, 08:02 AM
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Architecture & Porsche's
Join Date: Jan 2006
Location: Austin, Texas
Posts: 3,189
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Not like you need another motor But I have a complete one
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Porsche Club Racing National Scrutineer '89 Andial 951 '82 928R '74 911 RSR 3.6 |
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05-26-2016, 10:02 AM
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Architecture & Porsche's
Join Date: Jan 2006
Location: Austin, Texas
Posts: 3,189
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Seriously though, email Chris Carroll @ TurboKraft, he knows head work like nobody else in this industry.
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Porsche Club Racing National Scrutineer '89 Andial 951 '82 928R '74 911 RSR 3.6 |
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05-26-2016, 10:03 AM
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Took it over to Brooks Elliott locally -- Good guy who I trust.
Its cracked up and under the liner, valve seat looked ok and valve seats fine. Maybe when it heats up it has problems? Plan at this point is to find a replacement once I get the the exact deck height measurement. I also have a set of 964 heads for 3.8 cylinders but this case is a 3.6. Mike
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2015 Panamera Hybrid, 2008 Cayenne Twin Turbo 2001 996 GT2 1999 Spec Boxster, 1996 993 Cabriolet 1992 964 Cabirolet, 1975 911 RSR Replica Race Car |
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05-26-2016, 10:11 AM
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Location: Ontario Canada
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that's odd that you say it leaks smoke through the exhaust vale yet the valve seats fine .. something is a miss. But you are right, end of the day you still need a good head ......
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1976 Yamaha XS360 ( Beats Walkin') 1978 911 SC Targa ( Yamaha Support Vehicle ) 2006 Audi A4 2.0T (Porsche Support Vehicle ) 2014 Audi A4 2.0T Technik (Audi Support Vehicle) |
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05-26-2016, 10:23 AM
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Sourced a Cylinder head from Autobahn Dismantling out of San Diego.
Hats off to those guys -- ordered Thursday -- if arrived at my house on Sunday afternoon. Shrink wrap packaged and looked to be in excellent condition. Had complete valve train and plugs too (not that I needed that) -- and a pretty reasonable price to boot. Will replace the exhaust valve which looks blackened and have a valve job done and reassemble the engine. fingers crossed we can get this all done quickly! Mike
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2015 Panamera Hybrid, 2008 Cayenne Twin Turbo 2001 996 GT2 1999 Spec Boxster, 1996 993 Cabriolet 1992 964 Cabirolet, 1975 911 RSR Replica Race Car |
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05-31-2016, 09:28 AM
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Marble Grey
