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Registered
Join Date: Feb 2002
Location: Central NJ
Posts: 568
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2.7 Piston carnage...
Well, I'm slowly getting into the 2.7 out of the 76 I bought a couple of months ago. Engine was smoking consistently, low compression on most cyls. PO said that it started smoking after he installed the dist 180 deg out of phase...
Well, I think something was dropped inside the cylinder. What do you guys think of this damage. Looks like there are two piston chunks missing, along with cyl wall scoring. Also, the head took a beating... Will eventually need a new head and cyl. Did 2.7 come with Mahle cyls? I counted 11 fins and the base of the cyl has the "m" next to the triangle with the cyl height and size tolerance... Lou   
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'76 911 "Moneypenny" daily driver '74 911 "JLo" IROC DE Car '03 CRV, '02 Jeep Grand Cherokee '03 Holiday Rambler Admiral SE, 30ft, 8.1l, 340HP, 455Ft# http://www.nicotra4.hpshare.net/BasketCaseMotorsports/ |
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02-14-2006, 06:04 PM
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Join Date: Aug 2004
Location: G.R. Mi.
Posts: 225
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put a magnet on the cylinder wall. If it slightly sticks it is a nikasil if not
it is alusil
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Denny 1976 911s targa 1974 widebody G2 style GroupeB 76 www.G2Performanceshop.com Cylinder head recon, case savers,twin plug,rocker arms |
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02-14-2006, 06:13 PM
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Join Date: May 2003
Posts: 3,346
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The color of the cylinder looks like Alusil. The magnet test will tell more. If it's Alusil you should be able to find another cylinder cheap.
-Andy
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72 Carrera RS replica, Spec 911 racer |
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02-14-2006, 06:38 PM
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Join Date: Apr 2004
Location: Santa Cruz Ca
Posts: 782
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Looks like the classic hole in a piston. Typically detonation cracks the area above tht top ring groove, pieces fall out and bounce around in the cylinder until being expelled through the exhaust. Less severe cases would just show a burned notch in the same area and no head damage.
Phil |
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02-14-2006, 07:49 PM
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Join Date: Jul 2002
Location: Sydney, Australia
Posts: 2,477
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that doesn't look too bad at all
you should have seen the piston that was hitting this... 
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Cheers, Ryan 1969 911E (historic racer) 911ST replica (tarmac rally) |
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02-14-2006, 09:27 PM
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Join Date: Jun 2001
Location: Sweden
Posts: 5,911
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Naah, it looks like knock induced cylinder erosion to me. Eroded piston edges w/o marks in the middle is a tell-tale.
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Thank you for your time, |
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02-15-2006, 01:26 AM
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resident samsquamch
Join Date: Oct 2005
Location: Cooterville, Cackalacky
Posts: 6,815
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Quote:
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-jeff back in the saddle: '95 993 - just another black C2 *SOLD*: '87 930 GP White - heroin would have been a cheaper addiction... "Ladies and Gentlemen, from Boston Massachusetts, we are Morphine, at your service..." - Mark Sandman (RIP  )
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02-15-2006, 02:14 AM
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Join Date: Jul 2002
Location: Sydney, Australia
Posts: 2,477
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sand man
motor failed day 1 of a 4 day rally. over-rev lead to bent valve which then broke and the valve head dropped into the comb'n chamber. it all went pear shaped about 200m from the end of the last stage of the day. not what you call a good day... however, the rebuilt motor is even better... len911 - sorry about the thread hijack!
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Cheers, Ryan 1969 911E (historic racer) 911ST replica (tarmac rally) |
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02-15-2006, 02:32 AM
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