 Question for Six Engine People, TDC and Z1 mark |
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| Robarabian |
 Mar 15 2023, 08:48 PM
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#1
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914 A Roo  Group: Members Posts: 687 Joined: 11-February 19 From: Simi Valley, Kalifornia Member No.: 22,865 Region Association: Southern California 
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I have a 911 engine I am working on. I am practicing setting cam timing so I can feel comfortable with it prior to the tear down. My Crankshaft pulley has a Z1 mark that has 2 lines. So I have seen 911 pulleys with Z1 and 1 line.
The question de jour is which of the 2 lines at Z1 is TDC? Or are the 2 lines giving me the dwell of where TDC is and if so, where should I put them in relation to the case to set cam timing and do valve adjustments. it looks like " Z | | 1" It is a 2.4 Somebody knows this answer. |
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| IronHillRestorations |
Mar 16 2023, 03:06 PM
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#2
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I. I. R. C. Group: Members Posts: 6,813 Joined: 18-March 03 From: West TN Member No.: 439 Region Association: None
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To add confusion the 2.4 and 2.7’s crank is indexed differently than the 2.0 and 2.2’s.
You can use a 2.0 (same as 914-6) flywheel on 2.0-2.7 and it will bolt up, but with 2.4 and 2.7 the timing marks on the flywheel will be off. I always re-mark Z1, 35*, 120*, and 240*. With a 6 it’s much easier to set the timing and adjust the valves using the marks on the flywheel. |
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| Robarabian |
Mar 16 2023, 06:45 PM
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#3
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914 A Roo Group: Members Posts: 687 Joined: 11-February 19 From: Simi Valley, Kalifornia Member No.: 22,865 Region Association: Southern California
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I was wondering about that. I installed a new flywheel on the 2.7 motor when I was working on it and was confused about why the Z1 mark on the pulley didn't line up with the Z1 on the flywheel. I ended up marking it as you said.
QUOTE(IronHillRestorations @ Mar 16 2023, 02:06 PM)  To add confusion the 2.4 and 2.7’s crank is indexed differently than the 2.0 and 2.2’s. You can use a 2.0 (same as 914-6) flywheel on 2.0-2.7 and it will bolt up, but with 2.4 and 2.7 the timing marks on the flywheel will be off. I always re-mark Z1, 35*, 120*, and 240*. With a 6 it’s much easier to set the timing and adjust the valves using the marks on the flywheel. |
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Posts in this topic
Robarabian Question for Six Engine People Mar 15 2023, 08:48 PM
Robarabian I may have found the answer looking at 50 differen... Mar 15 2023, 08:57 PM targa72e That is correct . 911 of that vintage had vacuum r... Mar 15 2023, 10:33 PM Krieger I think the 5° BTDC is the timing mark at idle. I... Mar 15 2023, 10:33 PM ClayPerrine A suggestion for setting the cam timing.
Only pu... Mar 16 2023, 05:28 AM gereed75 I would emphasize one of Clays comments -put a dia... Mar 16 2023, 09:57 AM 930cabman I would double check with a dial indicator Mar 16 2023, 11:58 AM
Robarabian So my pulley actually has the Z1 mark and the seco... Mar 16 2023, 06:43 PM |
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