So, last night I went through the Paul Yaw notch the timing pully method and got the leading timing set right at 24 degrees of advance (@ 4000 rpm). However, when I check the trailing timing its way more advanced than the leading?!? It should be 8 degrees less than leading, not way more! What's the deal?

I've got an '80 RX7 with an '83 distributor and '83 ignitors. I'm not running any vacuum advance. I'm pretty sure all the wiring is correct.

Thanks for your help!!

-BeaterRacer

 

did you degree your crankshaft to see hwere your advance was?

 

Also trailing coil is the front coil and trailing plugs are the top plugs. If your lead is correct see what it is at idle and set the trail 8 degrees before that. The split will remain the same because the advance affects both equally.

 

I took the pully off when the engine was cranked over to TDC. I am assuming that the pully was not 90, 180 or 270 degrees off, cause the motor ran well (and it shouldn't run well if the timing is that much off). So, I'm pretty sure I know where TDC is.

Also, even if I was wrong about TDC, that wouldn't change the fact that my trailing plugs are firing ahead of my leading ones, aka they have more advance than my leading plugs. That makes no sense to me. With the leading plugs firing at 24 degrees past TDC, the trailing plugs should be firing at 16 degrees past TDC per Paul Yaw. Mine were firing at maybe 45 degrees past TDC. Way off my timing marks so hard to say exactly how advanced they were. Doh!

 

I do have the wiring correct as far as which coil goes with which plugs. Trailing on top, yes.

 

Did you say you set the timing to 24 degrees *past* TDC? That's wrong. Paul Yaw recommends 24 degrees *before* TDC. "Advance" means advanced before TDC, not after. I think you should double check what you're doing here.

BTW, as far as I know it's impossible to move the vacuum pots far enough to get the trailings to fire before the leadings. In fact, you'll be moving them close to all the way just to get the 8 degree split.

Be very careful with 24 degrees of advance - that's walking the razor's edge. You had better be sure you're running proper air/fuel mixtures. BTW, with a stock carb, stock jetting, no emissions and full exhaust you will *not* be running proper mixtures in my experience. Sorry if you already know this - it's just that I and others have almost paid the price for fooling with this stuff in the past.

If you aren't sure about this, a much better setting is 1 or 2 degrees of advance - no more than that. I actually like the feel of that better than the Yaw settings.

 

Hey, thanks for calling me on my mistake. When I said past TDC, I should have said before TDC. I set the timing for 24 degrees of advance at 4000 rpm. That roughly equals 4 degrees of advance at idle. That's 4 degrees past the factory white mark. So, when you (Silver Rocket) say 1 or 2 degrees of advance, you are talking about at idle. That should be made clear.

So, let me restate my previous post. "With the leading plugs firing at 24 degrees BEFORE TDC, the trailing plugs should be firing at 16 degrees BEFORE TDC per Paul Yaw. Mine were firing at maybe 45 degrees BEFORE TDC. Way off my timing marks so hard to say exactly how advanced they were." Its crazy, but what I'm seeing is the trailing plugs firing before the leading ones. Essentially I think I'm running w/out the benefit of the trailing plugs. I think they're firing before the rotor even gets around to them.

Secondly, about the setup. I'm running a Weber 48 IDA carb w/ a RB header and exhaust. And its a beater (hence my login) so I'm not too worried about my 24 degrees of advance. Plus, a rotary is a low compression engine, so there should be no worries until you get out to around 30 degrees of advance at 4000 rpm or until you hear detonation (pinging).

No solution to my problem yet . . . it'll come. Someone must have had this problem before. . .

 

There are only two ways that is possible.... either the wires between the trailing pickup coil and the trailing ignitor got flopped postive for negative (which will advance its timing by 30 degrees) or you have your trailing and leading ignition flopped.

It is not possible to advance trailing that car in relation to leading, there just isn't enough adjustment. Something therefore is way wrong.

 

Just be sure to watch your spark plugs - a few of us have had problems with breaking sparkplugs at these levels of advance. That said, it shouldn't happen if everything else is set up right. You might wanna run some colder plugs just to be sure (ie. the FC/FD trailing plugs)

Sorry, I was kinda vague. What I meant was, 1 or 2 degrees more advanced than the stock settings all round. It doesn't matter whether it's at idle or anywhere else, just a couple degrees more than stock.

 

Okay, I will keep an eye on the plugs. Thanks for the help!