# timing chain installation - how to line up dots?



## thrashercharged (Sep 14, 2015)

Follow up to my 2 piece harmonic balancer question - I'm putting in a new timing chain as my old one skipped a few teeth. When I install the new chain, I'll turn the engine so the the crank gear's indicator dot will be at 12:00 (pointing straight up). How should I position the cam? 

On every other engine I've worked on, the indicator dot on the cam gear would be placed at 6:00 (pointed straight down) and directly across from the crank gear indicator dot. But I read on the web that with these Pontiac V8s you line up the dots 12:00 to 12:00? (i.e., both cam and crank dots pointed straight up). Is that right? That's to make #1 in the usual place, which is on the terminal nearest the firewall on the drivers side right?


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## geeteeohguy (Feb 2, 2008)

12 on the crank and 6 on the cam will work just fine. Then rotate the engine 2 times and verify that everything including the rotor is still lined up. Piece of cake.


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## oldskool (Apr 26, 2015)

Yeah, it's easier to line 'em up, with the dots together. But, that will put the #1 piston at TDC on it's exhaust stroke. So, the rotor will need to be pointing to #6 plug wire terminal.

If you line up both dots in the 12 O'clock position, the #1 piston will be at TDC on it's compression stroke. This means the rotor will need to be pointing to the #1 plug wire terminal.

This info is very important if the dist has been removed. Lots of guys, including me, have installed the dist 180 degrees out. The engine won't run that way !


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## Red1970GTO (Jun 25, 2011)

*What Year Engine*? Older Pontiac engines used the 6 & 12 method, whereas newer Pontiac engines use the 12 & 12 locations.


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## BearGFR (Aug 25, 2008)

Red1970GTO said:


> *What Year Engine*? Older Pontiac engines used the 6 & 12 method, whereas newer Pontiac engines use the 12 & 12 locations.


Actually, it doesn't matter. Just like oldskool said. Remember that the cam turns exactly once for every two crank rotations, so if you install the gears "dot pointing to dot" (12 and 6) and then turn the crankshaft exactly one revolution, you'll then be at 12 and 12. Install however you like. Use a straight edge through the crank and cam centerlines to help you make sure you've got things properly aligned (12 and 6, or 12 and 12). Turn the crank until the cam gear dot is at 12 (if it's not there already), then when you do finally get around to installing the distributor wire it so that whichever plug terminal the rotor is pointing to goes to #1 plug, wire the rest of the cap (counter clockwise) in firing number order, and you'll be set. If you want to orient things they way they would have been from the factory "fiddle with" the distributor until you can get it fully seated and the rotor pointed "more or less" towards the driver's seat (this is still #1 as long as you haven't turned the crank any), the vacuum advance canister aimed at the drivers side fender.

Bear


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## thrashercharged (Sep 14, 2015)

Ok, this makes sense. Thanks guys. 

I put the crank dot @ 12:00 so that #1 was at TDC, got cam dot at 12:00 (so both crank & cam are at 12:00) and installed the distributor so that #1 is the usual terminal and pointed it at the drivers seat. This way I have enough room to turn the distributor clockwise to get some advance in the base timing without the vacuum advance module hitting the valve cover.


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