timing marks

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Old 09-17-2012, 10:17 PM
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Default timing marks

I bought an 350 engine out of an 88 z28, and i put a new timing kit in it while it was out of the car. Now its in the car all hooked up and i cant get it to run. Im pretty sure its a timing issue, it turns over but wont catch, and back fires out the intake a lil bit. I brought the first cylinder up to top dead center, and reset the distributer at least 5 times now, every thing looks like it should work but its not running. Now when i put the timing kit in the engine, my hanynes manual told me to align the marks on the two sprockets so that the top one is at 6 oclock and the bottom one is at 12 oclock. But i looked it up on my friends computer and it showed the marks at 12 and 12 oclock. So i pretty much pulled most of the front of the engine off so i could get to the timing chain again, and am planning on switching it to 12 and 12, but the haynes manual clearly says 6 and 12. wtf does anyone know which is correct?
 
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Old 09-17-2012, 10:26 PM
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everything im seeing online says 12 and 12
 
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Old 09-17-2012, 10:43 PM
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well thats good news, i dont want to pull all that stuff off for nothing. thanks
 
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Old 09-17-2012, 10:46 PM
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usually a backfire means 180 out so either cyl 1 is at bdc or the cam is upside down.
 
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Old 09-17-2012, 11:18 PM
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Originally Posted by BasicConcepts
or the cam is upside down.
How do you put a cam in upside-down?
Take a look see at the illustration below. 12/12 is correct for TDC #1. You can set the marks facing each other with the engine at TDC #6, but then turn the engine over to TDC #1 before doing anything else. TDC #1 on the compression stroke is what you always want to pay attention to when installing the distributor.

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Old 09-17-2012, 11:28 PM
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Originally Posted by BasicConcepts
the cam is upside down.
thats frickin hilarious
 
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Old 09-17-2012, 11:34 PM
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If this guy installed the cam upside-down, and the distributor inside-out, he's really gonna be lost!
 
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Old 09-18-2012, 02:13 AM
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you guys know what i meant... sheesh...
 
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Old 09-18-2012, 07:34 AM
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The proper way is to have the top sprocket dot at 6 and the crank sprocket dot at 12. When you install the distributor like this you will need to FIRST rotate the crank 360 degrees and ONLY THEN set the distributor with the pointer facing between the water neck and the valve cover. AS OF NOW you only need to reinstall the distrubutor 180 degrees and you should be set. The crank turns over TWO times for the cam to rotate ONCE. You can do a 12 to 12 or a 6 to 12 and the timing will be the same, just remember the 2-1 crank to cam. Pointer to the front or to the back depending on the timing chain marks. JUST ROTATE IT 180 DEGREES before you do all the work over first and try that.
 

Last edited by YAV8; 09-18-2012 at 07:39 AM.
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Old 09-18-2012, 12:03 PM
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I think we may be getting overly complicated with the TDC #1 and #6, turn this, rotate that info.
What it boils down to is.... timing gear marks pointing at each other = TDC cylinder #6 compression stroke.
Both marks at 12 o'clock = TDC cylinder #1 compression stroke.
With both marks at 12 o'clock, the distributor rotor wants to point to the #1 wire on the cap.
 

Last edited by Camaro 69; 09-18-2012 at 12:08 PM.


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