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Registered
Join Date: Jul 2000
Location: Northampton, PA, USA
Posts: 334
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Quick cam sprocket question...
Was just about to button up the timing chain housings on my 3.2 after top end/rings/rod bearings and a voice in the back of my head said "just check one more time". I turned the engine over, and the right side chain was binding on the cam sprocket- as though it was out of alignment. I think I may have the sprocket installed incorrectly- is the right side sprocket supposed to be flat side away from the cam? I have it the other way right now...
Thanks!!
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Mackskibum aka Dave Austin '66 911 Work In Progress (#303734) '85 911 Carrera 06 325XI '05 Envoy XL SLT |
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06-04-2007, 04:19 PM
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3.4 Bigger is better
Join Date: Nov 2003
Location: South Dakota
Posts: 1,497
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The right is flat side out. Left is flat side in. I was in bed one night and panicked that I put them on wrong. A person can never take too many pictures.
 Left Side 
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Michael 88 911 Diamond Blue CE Carrera 3.4 HC3.4 member 2020 Honda Passport |
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06-04-2007, 05:05 PM
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Registered
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Location: Northampton, PA, USA
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Thanks Michael. That's what I was afraid of. Got to get the Z block back out again.
I agree on the pictures- the one photo I didn't take was the one you posted. Back to the shop...
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Mackskibum aka Dave Austin '66 911 Work In Progress (#303734) '85 911 Carrera 06 325XI '05 Envoy XL SLT |
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06-04-2007, 05:14 PM
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3.4 Bigger is better
Join Date: Nov 2003
Location: South Dakota
Posts: 1,497
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Good catch. Better now than it could have been.
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Michael 88 911 Diamond Blue CE Carrera 3.4 HC3.4 member 2020 Honda Passport |
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06-04-2007, 07:25 PM
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Nice catch Dave!
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Chris ---------------------------------------------- 1996 993 RS Replica 2023 KTM 890 Adventure R 1971 Norton 750 Commando Alcon Brake Kits |
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06-05-2007, 06:03 AM
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I don't see how this could happen if you are doing the sprocket alignment procedure. You would find that you can't get them to align no matter how many shims you installed or removed. If you aren't doing the sprocket alignment procedure then you are taking a chance on the alignment being wrong and having excessive wear on the chains and sprockets.
-Andy
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72 Carrera RS replica, Spec 911 racer |
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06-05-2007, 01:39 PM
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Schleprock
Join Date: Sep 2000
Location: Frankfort IL USA
Posts: 16,639
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Agreed I can't see how this can happen if you are checking sprocket parallelism every time an engine is assembled. But I think a lot of people put things back together the same way they came apart (for the most part......... i'll get to that in a second) and don't think twice about it.
My one data point of experience is on my recent top end build. In taking apart my engine, I found the right cam sprocket was on backwards (dish side facing out) with only one shim. So I put it back together with the dish side in and four shims. Parallelism measurement checked out okay. Sprocket shows some side wear on it and i'm sure the sprockets on the countershaft, plus the countershaft bearings themselves, show some thrust wear as well. We'll find out next time I open up the engine in another 78K miles! I'm hoping the odd growling/clattermy engine had will be remedied by getting the sprocket in the right orientation. I didn't replace the sprocket, nor the chain (since I didn't split the case to be able to do the countershaft sprocket) so it's not been restored to like new condition. But it's gotta be better than how it was with the wrongly oriented sprocket!
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Kevin L '86 Carrera "Larry" |
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06-05-2007, 02:06 PM
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1970 Porsche 911 S 
