Hey folks, I know the subject has been done to death. I've done a lot of reading and I want to go over my understanding of the process. My brain works weird, and I want to be mostly sure I'm on the right track.

Background: The timing line on my balancer may not actually be real TDC, ie the mark is wrong on the harmonizer. I want to make sure it is, and then set my timing in a "proper way". I just moved the line to the 0 point line. I have no idea if the line on the balancer is correct. I popped open the distributor and the rotor is around the 5 mark, which to my understanding may be wrong, unless the harmonizer is set to another spot. Running a timing light on it last night at idle, it was way above the 0 line, like if it were PTDC but 30 above.

My end goal is to set TDC to the proper spot, and then set my timing from there, so the reference going forward is solid and where it should be. Here is my understanding of the process.

1.) To set TDC, put something in Plug 1's place, rotate clockwise until the piston hits the rod, in my case I bought a threaded tool for this. Mark the position on the harmonizer, then back it out counter clockwise, when it hits, mark it again. At this point TDC should be at the halfway point between the two. Mark that. Take the thing out, rotate it so meets 0 on the timing marker bolted above it.

2.) Check the position of the rotor in the distributor. Ideally this would be pointed at the 1 spot. If not, unscrew the screw below the distributor, lift it out a little ways, rotate the rotor forward, drop it back in, and keep doing that till I hit 1. I'm under the assumption I have to do it bit by bit to make sure the distributor sits correctly. I could use some clarity on here.

Secure the distributor to where you can rotate it, but not where it is so loose it can spin freely.

Put plug back in and reconnect anything.

At this point I should be at TDC and ready to adjust timing.

3.) Unplug and plug the vacuum advance port on the carb. Fire up the engine, let it warm up. First, adjust to BTDC, which for my engine according to the service manual is at 6. I imagine I'd set my Timing Light to 6, and then back the distributor Counter Clockwise till it hits 0 again, making the initial timing 6 degrees BTDC.

4.) From there, have a buddy rev the engine up to 2500-3000, while I keep an eye on the timing position. If it's stabilized, assume that the centrifugal advance is stable and things are likely OK. In the book advanced timing at 16 degrees at 2400 RPM, which would give me a total advance timing of 22. 6 BTDC + 16 Advance. So I should set the Timing Light to 22 and if at 2400 RPM it lines up with 0, theoretically, that's the proper timing. I see the number 36 thrown out a lot. I could use some clarity on that, but the manual says 16 @ 2400, 22 @4200. I imagine if it sounds "off", adjusting that further out may be warranted. (L48 Auto if that matters).

Pending a test drive and real world circumstances, I should be good. Theoretically at least.

And I know, done to death, I just don't wanna f' anything up. Have mercy.

Do I understand the process correctly?

 

34-36 degrees total mechanical at around 3000rpm will yield max power for your 350.
22 degrees advance works, but it’ll just make less power.

 

It’s good that you’re checking top dead center on your harmonic balancer (not harmonizer, although that sounds nice.) If the mark you come up with doesn’t line up with the mark on the balancer I would look at replacing it sooner than later.

If your car is running in its current condition I would not remove the distributor. It spins at half of the speed of the crankshaft, meaning that if it’s pointed at the 5/6 terminals it’s halfway back to the #1 terminal.

The timing recommendations in your manual are for meeting emissions requirements, if you live in a state that doesn’t test for emissions you can throw those numbers out the window and use the 36 total. Of course with this timing spec, if you’re not already, you’ll want to run premium gas.

Most distributors in these cars have springs in the mechanical advance that don’t allow full advance until just about redline. If you don’t have lighter springs in the distributor already you won’t get your full advance at 2,800-3,000 RPM. You can get spring kits online for around $10. Get one of those and throw the weights that come in the kit in the trash. I’ve found that one medium and light spring works pretty well.

 

If you’re a fan of technology, check out progression distributors. Electronic distributor, with timing table created/edited from your cell phone. Very customizable, very cool.

 

When you checked the timing, was the vacuum advance disconnected?
If you discover the mark on the harmonic balancer is off, you stop, you do Not start to set your timing, you replace the balancer.

 

Harmonizer. Musician brain.

That's what I'm wondering. Part of it is whoever worked on this car before half assed a lot of things. I found vacuum disconnected. Rotting fuel line used as vacuum lines. Half the stuff in the interior not working right. The choke not even connected. She runs, and she runs pretty good now (better than she did 2 months ago), I'm just kind of OCD about these things. If I can make it "correct" at least, I've righted a wrong someone else did. It just feels like someone threw stuff in there and didn't really take the time on it. There's a line painted on the balancer, and I know it should have a default line, I'm wondering if they just f'd up painting it on there. I probably should look closer at it and make sure. I might be worried about nothing. I'm ok with the idea of eventually replacing the balancer, and throwing in a new timing chain and gears, I feel like right now that might be over my head. This car has done a lot to build up my confidence in what I'm willing to take on, and I know I'll have to be at that point sometime.

And yes, I disconnected the advance and plugged the port on the carb.

If things are working at least, should I not worry about it for the summer and maybe in the fall take her apart and replace stuff?

 

Now that's really interesting. Just googled it. Do you have one?

 

The balancer has a groove in it that painting white makes more obvious. Any other painted line is a bandaid for a problem.

 

Checking your harmonic balancer should be the first step, check out this thread of one that went bad:

This is why the Forum always asks for photos and videos

 

Big yikes.

 

5:00 is perfect if it corresponds to the tower where the #1 plug wire enters the cap. Many folks think it has to point to the #1 cylinder on the block, but that doesn't matter – it's the spark plug wire terminal that matters.

Post a pic of your timing cover. There are several that can fit a small block but their timing tabs are in different places. Before going through a whole host of gyrations, make sure the components you have are designed to work together.

It doesn't really make a difference setting initial timing to 6°. What matters is setting timing so all of your mechanical advance (vacuum still disconnected) happens around 3000-3600 rpm and letting your idle timing fall wherever it does. This gets long-winded to explain and Lars Grimsrud has already done exceptional work laying it out in his timing papers. Email him, and ask for his timing and vacuum advance paper(s). v8fastcars@msn.com

The "manual", if GM or following GM specs, is intended as a general, all climate, emissions-passing setting. It's not a performance tune that gets out of the engine all of its potential.

 

Top is driver's side, bottom from passenger. The painted line is where the marker is supposed to be.

 

Something is very wrong with those pictures. What cylinder is the distributor rotor pointing to? A picture if possible.

 

It's around 2 right there.
As things are.

 

I do, and I’m a huge fan. Runs great and it’s very cool. and if you have any modifications on your motor, or are planning on it, it’s very helpful.
retards timing during starting, for easy starts. Very easy to wire in NOS timing, or just different tunes for different octane fuels.
if you have a big cam you can easily run lots of timing at idle, and easily still have perfect 36 degrees at whatever rpm you choose by just typing in numbers instead of guess and check with springs.

 

So not sure what the point of your pictures are. At 1 TDC where is the grooved painted line?

 

I have no idea. I’m not even sure if TDC is set properly, hence wanting to see if I could set it straight and go from there. When I had the line at 0 earlier today, it was pointing at 5, but I’m not sure if the line is even correct. The two possibilities I see are that previous owner really half assed something, or now that something might be terribly wrong. So I think when stuff cones in, I want to find what TDC actually is, and then see where the rotor points.

But it runs, I don’t hear any knocking. I had issues last week at 2500 RPM of it hesitating. Replaced the distributor cap, coil, rotor, and icm, and that issue has been gone since, except for one minor incident where it hesitated for a second and picked back up. I’ve probably put 200ish miles on it.

could the timing chain slip and cause all that?

 

The line when lined up with the zero mark on the tab will either have the rotor be near 1 or 6. The crankshaft makes 2 revolutions for one revolution of the distributor rotor.

 

so it was in the 5-6 range when I was messing with it earlier and lined it up. It might be ok then? I’ll test for TDC this week. I got a better timing light coming too, One with a dial. I’m done with it for today, but I appreciate you sticking with me here.

 

Are you talking about looking down from above the distributor like a clock with the "5-6 range"? It doesn't matter where it's pointed in relation to the engine. Where is the #1 spark plug wire connected to the cap in relation to the rotor electrode when the engraved balancer mark is at the -0- mark on the timing tab. Trace #1 wire to the cap, lift the cap just slightly off the distributor and make a Sharpie mark on the distributor housing where the center of the #1 tower is located. That's where the electrode should be pointing.

As MelWff said, the crankshaft turns two revolutions for every single revolution of the distributor rotor. With the engraved balancer mark at -0- on the tab, the rotor electrode will be pointing at #1 tower or the #6 tower (opposite #1 on the cap). If either of these positions are observed, then I wouldn't worry about pulling and resetting the distributor, or worrying too much about incorrect balancer, tab, etc.

A slipped timing chain doesn't have phantom effects. Once it jumps, the symptoms don't go away until the timing gears/chain is reoriented.

In your first message you said: What is PTDC?