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So I installed a new timing chain and definitely had both dots lined up correctly. I sent out the damper to get rebuilt (Damper Doc), so I know that should be good as well. I had to order a new timing chain as the old one
had the timing pointer break at the weld. But when I test fitted the damper, I got this:
My initial thought was to move the white mark on the timing pointer to meet the damper line. My assumption is that since everything else should be correct, the issue is probably the repop timing cover
pointer location? Thoughts?
Before moving on to the timing alignment on the damper, lining up the timing dots is oftentimes done in error. When the engine is at TDC on firing #1, the two dots are each located at 12:00 on their respective gears. To line up the two dots so that the cam gear dot is right above (6:00) the crank gear dot (12:00), the engine must be at TDC firing #6. The only way to judge which stroke you are on is to examine/measure the valve movement or observe the distributor rotor in relation to the plug wires if it hasn't been removed.
I assume when you typed
I had to order a new timing chain as the old one had the timing pointer break at the weld.
you meant timing chain cover. Did you compare your new cover with the old?
How are you measuring TDC? 2°-3° of crank rotation, as indicated in your pic, isn't very much at all. Most methods are just an estimate of piston movement.
1st things first, as 67:72 said your chain setup was wrong, but not a big deal. Pull the left hand valve cover and roll the engine clockwise until the intake valve opens and then closes, then crank CW to zero. Should be TDC. You can check that with a stiff wire through the spark plug hole. 2 people are good here, one to hold the wire while you twist on the crank, back and forth to verify TDC. Then if the marker needs adjusted you can do that. Check your distributor for proper alignment and start running through your copy of Lars Timing Papers.
Before moving on to the timing alignment on the damper, lining up the timing dots is oftentimes done in error. When the engine is at TDC on firing #1, the two dots are each located at 12:00 on their respective gears. To line up the two dots so that the cam gear dot is right above (6:00) the crank gear dot (12:00), the engine must be at TDC firing #6. The only way to judge which stroke you are on is to examine/measure the valve movement or observe the distributor rotor in relation to the plug wires if it hasn't been removed.
I assume when you typed you meant timing chain cover. Did you compare your new cover with the old?
How are you measuring TDC? 2°-3° of crank rotation, as indicated in your pic, isn't very much at all. Most methods are just an estimate of piston movement.
Ah you are right, I did line the dots up (crank/cam) on 12 oclock position initially and then I did spin it so they were 12 (crank) and 6 (cam) to better eye the alignment on the timing chain. So yea, I am on the #6. Will look again tonight and rotate the engine to #1 distributor timing
location. I have a piston stop to get it near TDC, but am never sure how far in the stop should go.
You can't assume that simply lining up the dots is going to get you at exact TDC. It will get the gears aligned correctly for assembly, but it's unlikely that you will get the crankshaft actually aligned at TDC within a couple of degrees. To do that, you need to do a TDC verification using a piston stop. You can e-mail me for my paper on how to do that.
04-02-2024, 09:55 AM
Tdc?
