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whosurpopi

Set timing question. 350 mag mpi

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2001 mag mpi lh rotation spec calls for 8 degrees before tdc.  Just to clarify, the mark on the balancer should be to the left of the notch on the block?  

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I would think so. If not remove the # 1 plug and turn the engine by hand.

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2 minutes ago, whosurpopi said:

I am referring to the notch on the balancer wile running with the timing light on.

Yes I know. But if you set the engine so the #1 cylinder is at TDC and make a mark on the balancer and the block. At lest this will mark zero. 

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I have zero,  I just want to know if 8 degrees btdc puts the mark to the left of right of zero

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I thought it was supposed to go to the left, but when I checked the other engine that runs good, it was to the right, so I copied that.  I just want to know if they are both wrong or right.

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3 minutes ago, whosurpopi said:

I have zero,  I just want to know if 8 degrees btdc puts the mark to the left of right of zero

Ok, which 8 degrees do you want? Most likely 8deg advance. BUT they do make digital timing lights that will display what you are looking for. I mean with a read out. 

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I thought the ECM looked after the timing. I haven't seen a timing light since modern fuel injection.

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Thunderbolt IV Ignition Timing 1. Connect timing light (91-99379 or similar) to No. 1 spark plug. Connect power supply leads on light to 12 volt battery. Refer to “Specifications” for cylinder numbering and location.
2. Connect tachometer to engine.
3. Start engine and run at normal idle speed.
4. Aim timing light at timing tab, located on timing gear cover and crankshaft torsional damper.
IMPORTANT: GM engine timing marks (on tab) are in 2-degree increments. MCM and MIE LH engines will have “A” (Advance) mark to the left of “0.” Timing must be set on the “A” side of “0” (Top Dead Center).

 

file:///C:/Users/User/Desktop/beach/16B4R2.PDF

 

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If you are in the boat facing aft looking at the crankshaft pulley and it turns clockwise with the engine running markings to the left of the indicator will be (BTDC) before top dead center. If it rotates counter-clockwise the marking to the right will be (BTDC) before top dead center. So if you have two engines and they are counter rotating to each other, the marks will be on opposite sides of the indicator. I hope this helps.

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I thought the counter rotation on twins was induced by the outdrive gearing, not the engine rotation???

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I have bravo 3's with dual props so no counter rotation.  On the engine cover it says they are left hand rotation.  I will check tomorrow,  yes it helps.  That is what I was looking for.

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