So I have a problem with my ignition system. When I gas her she goes up to around 3200 and starts "popping" from the exhaust almost like a rev limiter or something. I can really hear it with the glass packs also. I don't think this is pre-ignition since I've heard pinging in this car when I put some bad gas in it before. It's only when I'm really getting on it too. If I'm driving regular without getting on it it doesn't have a problem. I had bought a Summit HEI rebuild kit and thought maybe it's the stock inductive system experiencing coil "roll-off" where it's not able to keep up with the demands of the fast building RPM's. I recently picked up a Streetfire Ignition that's capacitive discharge and not inductive and I still have it. Also I'm running Streetfire 8mm heli-coil wires and have switched to Autolite Pro Series 8mm's that I had laying around. I've also pulled the distributor and replaced the magnetic pickup under the rotor twice now (on my third pickup but from the same company).

Here's my setup:

Stock GM distributor base, shaft and gear.
Summit rebuild kit (cap, rotor, coil) (I've also changed to the stock ignition coil with the same results)
Accel vacuum advance pod (currently disconnected)
Accel short plugs (576S)
Streetfire 5520 Capacitive Discharge Box (rev limiter set at 6500)
Streetfire 8mm wires
1040 Amp battery with 2 gauge wires
Initial Timing: 24*
Total Timing: 34*
Plug gap: .045

Now also thinking it could be a possible fuel delivery problem.

 

first response is to say are the valves set right. but i figure uve aready checked that. make sure the ground on the ignition is good. i have an on going problem with my netter that is very similar and have not got it nailed down yet either. it helped alot by changing the ground wire location to get a better connection. i think mine is ignition switch related, once the power draw gets so high it fails.

 

Yeah, I read on the MSD forums last night and sent them a tech request question. Hopefully will hear back about it. They're mostly talking about the internal coil needing to be grounded externally to the firewall or another good ground if you're running an aluminum intake which I am. I'll probably try that tonight when I get home.

I also think it might be a fuel feed problem also so I'm going to try going back to my original fuel feed setup and see if that helps. I have a 110gph pump so I find it hard to believe that it's fuel starvation unless my regulator is keeping it from pulling. It could be a kink in my secondary's fuel line.

 

Found out a couple of days ago that the rear seal between the block and the intake I just installed has a hole in it where the silicon didn't seal up or it got sucked through. I figure it was sucked since it hasn't been leaking till just recently. I'll fix it tomorrow and see if that fixes it.

 

Keep us up to date i would like to see how this one turns out.

 

Have you check the amount of play in the distributor? If the shaft is moving to much it will act just like a bad pick-up. You can hook spark testers inline and see if the spark fails. I like the old ST125 spark tests but any would do. Even Harbor freight carries them.
http://www.harborfreightusa.com/usa/...do?itemid=4424

It could very well be a lean condition. If it will do it by reving the motor hold it in a spot that will cause the miss for 10-20 seconds then kill the motor, do not let it go back to idle. Pull the pugs. They should be white-ish if it is leaning out.

 

Well I redid the intake and it didn't fix the problem. To check a lean condition I put a 3310 plate on the carb with 78 jets and a 2.5 pv and still had it around the same RPM. I can see that I'm running rich at this time when I nail it pretty hard as the black soot from a rich condition breaks for a second or two.

Gorn> It doesn't do it when the car is sitting, only when it's under load. There's no vacuum advance hooked up but the port on both the distributor and the metering block are capped. I'm really having a time with this and it's ticking me off. I would love to use the spark tester but like I said, it only does it with driving conditions. I have my initial timing at 22 with around a 10* curve that comes in right around 3k RPM but I can only check that with the car sitting and my hand working the throttle. I can figure out what would be causing it go higher advancing under load? I'm about 99% sure that this is my problem now. I've got three different curve kits with weights and springs from accel, msd and the stock set. It does it with all three. I've replaced the magnetic pickup twice now under the base of the rotor and made sure the air gap is right and centered. I don't feel any excessive play in the shaft (I know, "...that's what she said") when I work it back and forth horizontally but there is some play vertically that lets it move a little. I can't remember if this is normal or not. It gives maybe 3 - 6 degrees with it popping up like that but I really can't remember if that's normal operating movement.

 

What power source did you hook the distributor to? HEI ignition wants a good 12 volts going to it.
And, how come you have the vacuum advance disconnected?

 

HEI module is removed and using an MSD box with 8 gauge wires to and from the battery and then 10 gauge from the box to the 12 volt switch/coil. All the other wires are standard wiring harness gauges from MSD which I think were 14 or 16 gauge. The battery is a 1024 CA with 2 gauge cables. In dash voltmeter is reading 12 - 14 volts when cranked and 12 - 13 when off.

As far as the vacuum advance disconnected I have the initial timing set to around 22 degrees with around 10 degree curve. I have really good idle and off idle/throttle response. Also with the adjustable vacuum advance hooked up and set to it's lowest level it seems to want to throw the timing up into the 40's.

A friend of mine runs his weights locked with a locked out timing of around 38 degrees. I haven't gone that far yet to just rivet my weights down and just set timing to 30 some odd degrees. I know everyone's car is different for their applications but I'm beginning to think this might be the answer for me too. I can't seem to get stable timing with a curve applied.

 

Have you already tried...
Hooking up the vacuum advance, backing the initial timing down to about 10-12 BTDC, and adjusting the mechanical advance to be all in between 2500 and 3000 rpm? You said timing went up into the 40's with the vacuum connected, but was that with the initial still set at 22?
And just curious, do you have timing tape on the balancer, or are you using a dial back gun to check your curve and total timing?