Advance/Timing WTF

[jcd9730]

I decided to fix my timing today, since the mech. advance doesn't work at all (stuck or something). It was running smooth and pulled hard, but I got horrible gas mileage. Like 7mpg going easy.

So I followed the timing guide in the FAQ to a letter. Got the advance kit and adjustable can, and worked my way from the lightest weights to the heaviest, and every possible combination and methodically adjusting initial timing (keeping it around 38-30 total advance) and testing on full throttle runs.

Its now been 4 hours of this, AND IT WILL NOT STOP PINGING. Well, it did with one setting, but as soon as I plugged up the vacuum advance it did, and no adjusting that would stop the pinging at full throttle (ran good at part, or when slowly increasing speed, but at full with vacuum advance it pinged bad)

This working perfectly fine this morning, just with terrible mileage. Now trying to 'fix' it, I can't get it to stop pinging.

Its an Accel HEI, thats kinda old and dirty, but looks ok and ran great before I tried fixing the stuck mechanical advance.

WTF. Im getting pissed. This was SUPPOSED to be quick and easy

[geezer#99]

At full throttle your vac advance doesn't work. You have zero vacuum.
What's your initial timing at?
Not your total, your initial.

[jcd9730]

Everything. I've tried 5-14 for initial, and tested with every spring combo and cant get it to not ping

[Lee H]

How do you know the mechanical advance is working correctly?
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[jcd9730]

Cuz I put new weights/springs and I can see it. Good for about 23 degress advance

[Lee H]

What was wrong with the original springs?
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[Lee H]

Which spring kit did you buy?
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[jcd9730]

They were stuck and would not advance. I got the ones in the timing FAQ

http://www.summitracing.com/parts/mrg-929g

I even used the springs that came with the vacuum advance (same one in the FAQ too), and those did not help at all

[Lee H]

With the cap off can you advance the mechanical by hand and see it spring back real quick?
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[geezer#99]

Have you confirmed tdc on #1 with your timing tab and balancer?

[Lee H]

Originally Posted by jcd9730

Cuz I put new weights/springs and I can see it. Good for about 23 degress advance

Are you saying 23 mechanical? Or 23 with vacuum unhooked at about 2400 RPM?
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[gvw5400]

+1 with Lee H on post #9. I have experienced stuck/frozen mechanical advances on two different HEI dist. over the years. This may not be your issue but it does happen. Best regards in your battle!

[jcd9730]

Rotor does spring back, confirmed TDC when I did the head gasket. By the 23 I meant 23 mechanical with the springs in the kit.

I cleaned the old springs that were stuck on there and put them on. I set it with 10 initial and it only appears to be giving 15 mech. and isnt fully advanced until 3200rpms with these springs, BUT it does not ping! Though thats only 25 total..

Then I hooked the vacuum advance up. Runs smooth at part throttle, but again, pings like a mofo at full throttle. Which makes no sense to me, because with the vacuum can plugged, it does not ping at all at full throttle.

???

[jcd9730]

Its on manifold vacuum, btw

[Lee H]

Now we are getting somewhere, your getting way to much timing at part/full throttle with vacuum. You should be getting (nominally) about 12 at idle, 24 at 2,500 (no vacuum) and about 32 at 2,500 with vacuum. Looks like yours springs are to heavy & vacuum canister is pulling way to much advance.
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[Lee H]

Manifold vacuum is fine.
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[jcd9730]

With the old springs I just put in, its at about 26 total at 3000. I didnt look at 2500. I think the vacuum can is good for 11, but can't remember what was stamped on it right now.

But the vacuum can shouldn't affect the full throttle timing, which is whats happening now?

[geezer#99]

Or the vac advance pot link arm is hanging up and keeping the advance plate advanced when it's hooked up.

[jcd9730]

What do you mean?

[Lee H]

Originally Posted by geezer#99

Or the vac advance pot link arm is hanging up and keeping the advance plate advanced when it's hooked up.

Yes,
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[geezer#99]

THe link arm hooks into the advance plate. Could be hanging up on the dist body. Hook a vac hose to it and suck on it and see if the arm moves freely. You can feel it under the pot.

[Bigdav160]

Just an story.

I had a supercharge 406 I ran in several cars. The last install it would not stop pinging. I checked everything. Thought it might be fuel related. Checked that too.

A couple weeks goes by and the car dies going down the road. No spark.

Replace the Accel HEI ignition coil and it ran great with no pinging.

Weird.

[jcd9730]

Well I cant move it with my lungs, is that bad? I pulled off the cap and moved it with a screwdriver, it took a bit of force.

[jcd9730]

It could very well be the coil or something. I've no idea how old it is. I'm thinking about just getting a skip white one and calling it a day

[Lee H]

Originally Posted by jcd9730

Well I cant move it with my lungs, is that bad? I pulled off the cap and moved it with a screwdriver, it took a bit of force.

Yes, bad. Your distributor is honked up. You need to pull it and disassemble, lube, and reassemble. You should be able to move it with a short suck. I'd be getting a "GM" HEI and be done with it.
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