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Join Date: Jun 2022
Posts: 4
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Piston Type/Size/Compression?
I bought the car a few months ago and decided to scope it for future refernace as i modify it. Has anyone seen these pistons before? They look factory. They all leakdown test under 2%. I haven't seen any with these kind of gouge looking reliefs. Took me off gaurd for valve contact initially. They all look the same way. Car runs great. USA Car.
1982 911 SC. SSI Heat Exchangers, Scart Sport Muffler, Weber IDA40 Carbs, ITG Filters. These are the only modifications that I'm aware of. |
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06-14-2022, 01:12 AM
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06-14-2022, 01:27 AM
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New-ish 911SC Targa Owner
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what is the engine number stamped in the case where the green arrow is pointing at in the below picture?
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'83 Targa 300k w/ freshened 3.0 with 930/52 case# 6770540 ARP and Raceware hardware - AEM Infinity 506, Triumph T595 ITBs, B&B headers, Dynomax muff, Fidanza FW, Alum PP-203whp |
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06-14-2022, 01:03 PM
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64C0772. It's definitely been rebuilt/refreshed before looking at the seals and underneath the car. All of it looks almost new. Those pistons don't look like US low comp spec to me?
Thanks |
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06-14-2022, 02:44 PM
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Location: longbeach
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?max moritz?
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06-14-2022, 02:54 PM
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Location: Denver, CO
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Quote:
These look stock (or like these, that are represented as stock) to me -- Last edited by darrin; 06-14-2022 at 03:32 PM.. |
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06-14-2022, 03:30 PM
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Looks like a standard CIS piston to me.
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Jeff '72 911T 3.0 MFI '93 Ducati 900 Super Sport "God invented whiskey so the Irish wouldn't rule the world" |
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06-15-2022, 01:32 PM
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 Thanks for the replies everyone. The pic linked/attached is the closest that I've found. None I've seen have this valve relief that I have in mine. I suspect a higher compression 9.8:1 euro piston at maybe a larger 98+mm bore necessitating the need for this relief? |
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06-15-2022, 03:09 PM
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New-ish 911SC Targa Owner
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I don't see a valve relief in your bore scope images. I think it's an illusion and you have standard cis slugs.
Take it apart and find out! ;P |
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06-16-2022, 04:14 PM
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It's a 914 ...
Join Date: Jan 2008
Location: Ossining, NY
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I think the shadows in your borescope pics are playing tricks on the eyes. I agree that the piston in your pics matches CIS pistons. Not sure anyone bothered to make high performance versions of those things anyway.
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06-16-2022, 05:09 PM
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Join Date: Oct 2008
Location: Nash County, NC.
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95L67 Mahle casting number inside piston is standard US compression of 9.3 on a 80/83 SC
Bruce |
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06-17-2022, 01:16 AM
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Jeanine
