Suggestions on spark plug wires

[Gator]

I'm looking for a quality brand of spark plug wires to run with headers looking for some suggestions

 

[80mirada]

I would suggest some protective sleeves\boots, with MSD or Firecore. I have had good luck with a bunch of differen brands of wires though, Accel, Moroso, Taylor, MSD, Mallory, and Jacobs. If you can find a set Jacobs were available with a Ceramic and premium silicone sparkplug end.

Forget Jacobs, apparently they went down hill for quality after being bought by a competitor

 

[brotherGood]

I've got Taylor spiro pros..they were highly recommended to me, and I haven't had any issues with them. You can get them in a variety of colors too..

 

[M_Body_Coupe]

I've been using the Mallory wires, 8mm - Pro Sidewinder Series. If you are going to run the standard Mopar SB headers spend a little cash on the wire heat sleeves...especially on the #5 & #7 cylinders.

Also, I know you didn't ask, but it's nearly the same subject, had great luck with the NGK V-Grove spark plugs, BKR5E-11(#6953).

 

[Grandmas84]

X2 on the Taylor wires. That's what i have on my Fifth Ave.

 

[Gator]

That's were my problem is 5 and 7 I'll pickup one of those brands next weekend. I now this is a little off subject but I'm trying to tune my Thermoquad.I just rebuilt it.I'm getting a little bit of a backfire and hesitation not all the time any suggestions

 

[80mirada]

Check for vacuum leaks at the base. Are you running the stock insulator under the Thermoquad?

 

[M_Body_Coupe]

...but I'm trying to tune my Thermoquad.I just rebuilt it.I'm getting a little bit of a backfire and hesitation not all the time ...

Can you narrow this down to a specific scenario?

So one at a time:
1) hesitation
- off-idle, with any throttle openning, or is this the often encountered TQ complaint of "WOT pedal-to-da-metal and she stumbles" symptom?
- is this when the 2ndaries kick-in?

2) backfire
- when? is this tied in with the WOT in any way?
- what is your ignition timing like? initial and mechanical, how soon is it all in?
- what is your vacum can for the distributor set up like? assuming here a non-LeanBurn setup...

 

[Gator]

Hesitation is at wot. A slight Backfire every once in awhile when idling more like a rumble not a shotgun.I checked the timing it's at 2 degrees advanced

 

[M_Body_Coupe]

Timing is only 2 deg adv??? Wow...how is your ignition system configured? Are you running stock Mopar stuff (LeanBurn) or distributor with mechanical advance?

OK, regarding the WOT hesitation...we can make progress here...LOL...may be a bit tough to explain though...so how familiar are you with the Carter TQ?

Here are a couple more detailed questions:
1) do you know how to adjust the secondary air-valve tension? literally, how much spring loaded pressure is there that the engine air intake has to overcome before the secondaries really kick-in and start flowing fuel/air mix...
2) how far is your secondary air-valve openning up?
3) as best as you can tell, is everything else on your TQ configured/setup correctly and working as expected?

 

[Gator]

It's not lean burn.have mopar chrome box mopar distributor,1 I don't now how to adjust the secondary air valve tension.I think it runs pretty decent other wise

 

[Grandmas84]

It's not lean burn.have mopar chrome box mopar distributor,1 I don't now how to adjust the secondary air valve tension.I think it runs pretty decent other wise

I would think the chrome box is a little to much for a street driven car. Im sure someone else might chime in.

 

[NoCar340]

Chrome box is fine on the street. The primary difference between factory, orange, chrome and gold ECUs is the coil dwell time. The gold simply has too much dwell for long-term low-RPM use and will pull a murder-suicide involving the coil in pretty short order. The chrome may not last as long in daily use, but combined with a good aftermarket coil (it shouldn't be used with a stock coil) is a nice step up the performance ladder.

Initial setup and proper air-door tension on ThermoQuads are critical. Set up correctly, it's one of the best-running carbs you'll find. It's a damned shame tuning parts don't exist.

Anyhow, to make sure your TQ is up to par performance-wise, click here and make sure you've got ink and paper. Tell me you love me.

Go through the steps for linkage adjustments, then set the air door tension. The infamous "ThermoBog" is usually caused by air doors that are too tight rather than loose (it's a lean condition, not an actual bog). You don't need the special tool to do it; you can actually make a "one-time" lockscrew adjuster by grinding the end of a piece of steel brake line and holding it with a Vise-Grip. The biggest caveat to adjusting the secondary air doors: Do not let the center screw unwind itself! Don't even think of moving that lockscrew until you've got a screwdriver holding the adjuster, and make sure you snug the lockscrew again before removing the screwdriver! If all the tension goes out of the spring you're adjusting, it will usually unseat itself and will require disassembly to repair, so re-read the bold bit and the sentence immediately thereafter and avoid the hassle entirely.

 

[M_Body_Coupe]

...The infamous "ThermoBog" is usually caused by air doors that are too tight rather than loose (it's a lean condition, not an actual bog)...

Please explain further...and I'm talking as in the utter most painful detail(s) you can provide...

 

[NoCar340]

Without getting into too much into wall-wetting (X/Tau) discussions...

When you're cruising along at part throttle, you're under vacuum due to both the venturi effect on which carbs operate, and the restriction of the partially-closed throttle plate. Stabbing the throttle opens the primaries wide, as well as the secondary throttle plates. The accelerator pump's function is to give an extra fuel shot to the new influx of air, but it's only enough to cover it for a very short amount of time. This is why the car surges for a split second before the hesitation. On the secondary side, even though the throttle plates are open, the air doors aren't. Since the air doors aren't perfectly sealed like throttle blades, air gets past the various gaps in them. Until the air doors actually move, though, no additional fuel is added on the secondary side. There's your hesitation: the pump shot is used up, four throttle plates are wide open and moving air (only partially on the secondaries), but only two jets are moving fuel. For that moment, the engine falls on its face while it sucks accumulated fuel from the intake runners and port walls to burn with the extra air. Once it does that, it picks up speed and there's enough air speed to open the secondary air doors and metering-rod piston... and you're off like a shot. Loosening the air doors gets the party started sooner.

In reality, the accelerator pump's function is primarily to replace fuel lost from the intake runners and port walls, not to directly feed the cylinders. This is why acceleration enrichments are much trickier to get perfect on a multi-port engine: There's much less accumulated fuel to evaporate into the sudden increased airflow. There's also no venturi effect to draw additional fuel through the metering orifices, so that and the "accelerator pump" function need to be made up with increases in injector pulsewidth. Those increases need to be scaled to both the change in throttle position as determined by the sensor and change in overall load/air flow via either the manifold's absolute pressure on a speed density system, or actual measured airflow on mass-airflow systems. Better engine management systems use X/Tau calculations for acceleration enrichments, based on the evaporation rate of fuel from port walls v. airflow/manifold pressure as a function of time, rather than just sensor readings. Fun stuff.

When I'm thoroughly setting up a ThermoQuad or a Quadra-Jet, I loosen the tension enough to let the air doors open from gravity, then tighten just enough that the spring closes them (obviously, this is done with the engine off). I give it one more half-turn to tighten, secure the lockscrew, and test the car under load. Sometimes it needs to go tighter, sometimes it's good where it is, and even with it that loose I've had to loosen it a tad. As set from the factory, though, virtually every one to which I've done a "quickie" adjustment needed to be loosened.

 

[89.Fifth]

Without getting into too much into wall-wetting (X/Tau) discussions...

When you're cruising along at part throttle, you're under vacuum due to both the venturi effect on which carbs operate, and the restriction of the partially-closed throttle plate. Stabbing the throttle opens the primaries wide, as well as the secondary throttle plates. The accelerator pump's function is to give an extra fuel shot to the new influx of air, but it's only enough to cover it for a very short amount of time. This is why the car surges for a split second before the hesitation. On the secondary side, even though the throttle plates are open, the air doors aren't. Since the air doors aren't perfectly sealed like throttle blades, air gets past the various gaps in them. Until the air doors actually move, though, no additional fuel is added on the secondary side. There's your hesitation: the pump shot is used up, four throttle plates are wide open and moving air (only partially on the secondaries), but only two jets are moving fuel. For that moment, the engine falls on its face while it sucks accumulated fuel from the intake runners and port walls to burn with the extra air. Once it does that, it picks up speed and there's enough air speed to open the secondary air doors and metering-rod piston... and you're off like a shot. Loosening the air doors gets the party started sooner.

In reality, the accelerator pump's function is primarily to replace fuel lost from the intake runners and port walls, not to directly feed the cylinders. This is why acceleration enrichments are much trickier to get perfect on a multi-port engine: There's much less accumulated fuel to evaporate into the sudden increased airflow. There's also no venturi effect to draw additional fuel through the metering orifices, so that and the "accelerator pump" function need to be made up with increases in injector pulsewidth. Those increases need to be scaled to both the change in throttle position as determined by the sensor and change in overall load/air flow via either the manifold's absolute pressure on a speed density system, or actual measured airflow on mass-airflow systems. Better engine management systems use X/Tau calculations for acceleration enrichments, based on the evaporation rate of fuel from port walls v. airflow/manifold pressure as a function of time, rather than just sensor readings. Fun stuff.

When I'm thoroughly setting up a ThermoQuad or a Quadra-Jet, I loosen the tension enough to let the air doors open from gravity, then tighten just enough that the spring closes them (obviously, this is done with the engine off). I give it one more half-turn to tighten, secure the lockscrew, and test the car under load. Sometimes it needs to go tighter, sometimes it's good where it is, and even with it that loose I've had to loosen it a tad. As set from the factory, though, virtually every one to which I've done a "quickie" adjustment needed to be loosened.

Man, this is EXACTLY the kind of talk I live for. Please go into lots of detail.

 

[M_Body_Coupe]

...Until the air doors actually move, though, no additional fuel is added on the secondary side. There's your hesitation: the pump shot is used up, four throttle plates are wide open and moving air (only partially on the secondaries), but only two jets are moving fuel...

Yes, agreed. However, the engine response, or to be more precise, the rate at which it's capable of building the airflow in the 2ndary circuit is largely dependant on the overall powertrain combination. Therefore, a heavy car, with a sad 2.94 gear ratio will not build that air speed fast enough to quickly supplant the exhausted acc pump shot of fuel with steady flow of fuel from the 2ndary jets. Subsequently, one often finds that opening up the airdoor slower as oposed to faster (by increasing the tension) is what provides the smoother transition and therefore prevents the bog.

...When I'm thoroughly setting up a ThermoQuad or a Quadra-Jet, I loosen the tension enough to let the air doors open from gravity, then tighten just enough that the spring closes them (obviously, this is done with the engine off). I give it one more half-turn to tighten, secure the lockscrew, and test the car under load...

Very interesting, I'm curious what powertrain combinations (I'm talking converter stall speed, vehicle weight, gearing, etc.) you've found that respond to the quicker openning?

Here is where I'm coming from: I've always ran the TQs on all my M-body Mopars. While the near stock builds (aside for a slightly hotter cam and a bump in CR) liked the higher tension setting, I've found that my current combination with a 3.91 gear and 4K stall converter absolutely loves the quick openning. Actually, loves it so much so that I was pretty amazed how much "loser" I went with this particular setup...of course that translated to a near instantaneous "all-out" WOT response, no complaints there!!!

In fact, if there is one thing I'm puzzled by is the "air valve dashpot" setup, or in particular the spec. clearance between the air-valve and top housing...my 9800 series carb calls for about 0.030" while I've seen recommendations of as much as 0.200" in several forums posts...what does this pre-set actually control? As best as I can tell the wider it goes the quicker it allows the air-valve to approach the 2ndary jets and create the Venturi effect, which is ultimatley what will start the flow of fuel. What have you used in your setups?

 

[compubert]

I'm looking for a quality brand of spark plug wires to run with headers looking for some suggestions

I run non-resistor wires. 7mm from packard bell, if i remember right...

 

[NoCar340]

I should probably have noted that by a long shot my experience with ThermoQuads has been on high-performance engines, i.e. 340, 360, and big-block stuff. Transferring one to a 273 or 318 might require tightening due to the smaller amount of airflow present. In cases where I've done that, I've only done it with fresh rebuilds and set them up from raw. Truth be known, stuff like your coupe is what I daily drove my whole life, at least into my 30s. Fully five years of my daily driving were split between two 12-second cars, two years in my Trans Am and three in my Charger... even in the winter (which can be rather exciting, particularly with a stick). My '84 Fifth Avenue would be the car to which most board members would closely relate: ThermoQuad on a Performer intake (it was too corroded to sell--eventually the thermostat fell into the water crossover ) with a '73 340 distributor with Lean Burn delete. I replaced the 2.26:1 Sure Grip 7.25" rear with a 2.94:1 8.25". I remember that secondary adjustment being rather tight, really, as opposed to the 850 TQ I had on my 440 Charger. That car was a 2,600 stall & 3.23:1--still pretty tame but the secondaries were pretty loose. On my 4.10-geared Challenger 340/4-speed, you could move the air doors by blowing hard on them. They barely stayed up on their own, it seemed. It's really a matter of how fast the engine can gain RPM; swapping rear gears makes readjusting the tension a must if you want that "right now!" secondary engagement.

It was always my impression that air-valve dashpot setting is actually more concerned with deceleration. Dashpot is, by definition, a method of controlling the way an engine returns to idle. It's basically a controlled air leak; on MPFI engines it's a function of the IAC motor when the throttle is closed at high RPM or load. More dashpot means more air leak, which provides less engine braking. Generally speaking I just set it at the factory setting of the closest application I can find and don't worry about it. Honestly, I've never screwed with it as a performance adjustment. If it serves a function in that regard it's something I've not explored.

 

[NoCar340]

Board did something funky and I double posted... no obvious delete option, so you're reading this instead. Anticlimactic, isn't it?