Balancer spun?

[GT80]

1998 K1500 (5.7). Ok, so I got in a rush and did something stupid. In the process of pulling my distributor for a lower intake manifold gasket replacement I marked the distributor position but didn't mark the rotor position. So after making this mistake I brought #1 piston into the compression stroke by rotating the crank by hand and watching the rockers, and then I continued rotating until the mark on the balancer aligned with the mark on the timing cover. Assuming that was TDC I stabbed the distributor so that the button was pointing somewhere around the 5 o'clock position when facing the firewall (which I read was the approximate position) but when I put the cap down and aligned it to my marks the button is a few degrees past the #1 post. Is it possible my balancer (or timing cover) mark is off and I'm actually a bit past TDC? One tooth off is WAY more than the misalignment I am seeing. What I am seeing is more like less than 1/8 tooth. Do piston stops work ok with these Vortec heads? I read something about valve interference with those. I don't even want to try starting this thing without knowing I have it back where it was. I feel confident in the distributor clocking, I'm just confused why it's past the #1 plug post at TDC.

 

[GT80]

Now I'm starting to wonder if I should just go ahead and replace my timing chain set while I already have the front of the engine off. Probably so...

 

[GT80]

So I assume once I expose the timing set it should be pretty obvious if I am at #1 TDC. Is the timing cover a necessary replacement (considering what it says on the cover)?

 

[Schurkey]

It's more complex than being at #1 "TDC".

You could be at #1 TDC on the exhaust stroke, or #1 TDC on the compression stroke. If you're on the exhaust stroke, you line up the distributor and the engine will not run. You MUST be on the compression stroke when aligning the distributor for #1.

When you pull the timing cover, the dot on the crank gear should be at 12:00. The dot on the cam gear should also be at 12:00. If the crank gear is at 12 and the cam gear is at 6, (the way most folks want to align them) you need to rotate the crank one more turn.

GM clearly wants the plastic timing cover to be a one-use item. I expect it's possible to cram a new damper seal in place, and to use some Permatex The Right Stuff smeared on the existing rubber-y sealant to prevent oil leaks. However, I haven't actually done that.

 

[Erik the Awful]

When you pull the timing cover, the dot on the crank gear should be at 12:00. The dot on the cam gear should also be at 12:00. If the crank gear is at 12 and the cam gear is at 6, (the way most folks want to align them) you need to rotate the crank one more turn.

Here's a visual.

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[GT80]

Thanks for the replies. I get that part, and I'm almost positive I'm at TDC on the compression stroke because both valves remained closed on the way up. What's confusing is when the mark on the balancer is aligned with the mark on the timing cover, the rotor is just past #1 and I would expect it to be just before or right on #1. We'll see how she runs when I get her back together.

 

[Schurkey]

When you get it running, use the scan tool to get your cam offset right; and you're good to go.