Might be a dumb question, but are there alignment marks on a 350 harmonic balancer that would allow me to confirm that the outer ring has slipped? I remember reading on another thread that the keyway should line up with the timing mark but I haven't been able to confirm that myself. Thanks
Put cylinder 1 in TDC, with both valves closed (check rotor). Check if the 0 mark on the timing tab is close to or at the groove in the balancer. It looks like the keyway is in line with the timing groove on this 350 Buick balancer: Same on this image of a 350 Buick balancer:
Thanks for the info guys, I really appreciate it. I'm hoping that I can determine if my balancer has slipped since I hear pinging at WOT with timing set to TDC per the manual, maybe I have the timing set too advanced or there's another issue.
The manual means NOTHING unless you have the distributor that was installed at the factory. Initial timing is also irrelevant if you haven't checked where the advance is going at higher RPM. About a year ago, you posted about a 1111334 distributor. If that is the distributor you are using, it should only have 26-30* of mechanical timing. TDC initial timing should be OK and not cause ping. After you verify that your balancer has not slipped, you'll need to check your maximum timing (without vacuum advance).
Larry you are correct, the distributor I have installed in the car right now is a 1111334 which is what the car would've come with originally. I have also checked the degrees of advance at varying rpm to compare to the specs in the manual and they were within spec. Since I believe the distributor and advance mechanism to be correct then I figured with my pinging problem then there must be another issue somewhere which is what led me to take a closer look at the balancer, since if the timing mark is off them off course the timing would be off as well. This weekend I'll look at the balancer and go from there. Thanks again
Well got under the car today to look at the balancer and it doesn't seem to have slipped as I thought. Here's a couple pictures I took from the front, the keyway looks to be lined up with the timing mark as it should, let me know what you think.
I'm going to try to confirm the amount of mechanical advance today like Larry suggested. I did install an advance limiter bushing when I put the distributor together, maybe the bushing isn't limiting the advance enough? As for fuel I've been using 92 octane premium fuel with 1 gallon of 110 race gas per tank, so I think I'm good for gas.
Here are my results for testing total timing: First, I swapped out the stock springs for much lighter springs, they were copper colored from an advance kit I'd used before. Second, I have disconnected and plugged the vacuum advance for the test. With the stock springs installed the initial timing is set to 0°/TDC With the light springs installed and the engine revved up I got a reading of 27° of timing. With both of the light springs total advance occured at 2500 rpm, increasing rpm to 3000 did not result in more advance. From these results I believe the ignition curve to be correct and within spec for a 1969 1111334 distributor, which leads me to think my pinging issue lies elsewhere. I was considering swapping to a 180° thermostat instead of the 190° thermostat that's currently installed to see if there's an improvement, any thoughts?
