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Join Date: Oct 2006
Location: MYR S.C.
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compression and cam timing.
just a bit of interesting info.
I changed my cam timing on my 930 this week end by .015, retarded. my compression on number 4 was 130 before, it was 122 after. just thought it was amazing at how much the compression changed with just such a small amount of cam timing change.
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86 930 94kmiles [_  _] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD88 BMW 325is 200K+ SOLD 03 BMW 330CI 220K:: [_ _] RUNNING: [__] NOT RUNNING:01 suburban 330K:: [_ _] RUNNING: [__] NOT RUNNING:RACE CAR:: sold |
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07-12-2021, 06:09 AM
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Join Date: Oct 2019
Location: Ottawa
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[QUOTE=T77911S;11389143]just a bit of interesting info.
I changed my cam timing on my 930 this week end by .015, retarded. my compression on number 4 was 130 before, it was 122 after. Do you know why? Why not the other cyl in that bank at least. Phil |
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07-12-2021, 12:03 PM
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I only compared 1 and 4 before I change the timing, then did the rest after.
it affected all cylinders,
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86 930 94kmiles [_ _] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD88 BMW 325is 200K+ SOLD 03 BMW 330CI 220K:: [_ _] RUNNING: [__] NOT RUNNING:01 suburban 330K:: [_ _] RUNNING: [__] NOT RUNNING:RACE CAR:: sold |
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07-13-2021, 08:03 AM
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Join Date: Feb 2006
Location: Ontario Canada
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so are you telling us it was correct before and you intentionally retarded it ? or when you checked it , it was off from spec, so you corrected it ?
hard to tell what is going on from the limited info in your post.
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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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07-13-2021, 08:45 AM
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Join Date: Oct 2006
Location: MYR S.C.
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no,
one side was off by .015. #1 had a compression of 120psi, #4 had 130. after #4 was 122. point was changing cam timing by .015 changed the compression by 8psi. I just thought it was interesting that the compression changed that much. if my turbo was not in the way of the left side I might advance and retard the cams just to see how performance was.
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86 930 94kmiles [_ _] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD88 BMW 325is 200K+ SOLD 03 BMW 330CI 220K:: [_ _] RUNNING: [__] NOT RUNNING:01 suburban 330K:: [_ _] RUNNING: [__] NOT RUNNING:RACE CAR:: sold |
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07-13-2021, 09:55 AM
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