Low compression!!!

[ZHoob2004]

8 hours ago, zeiss150 said:

I have an electronic distributor from an 82ZX... so no points. 

And the coil is the original 72 240z coil. 

Are you still running the ballast resistor? The stock coil runs at a fairly low voltage thanks to the resistor, but the ZX ignition module was designed for a coil that operates at 12V. I would recommend losing the ballast resistor and swapping to a 280zx coil (you can try just bypassing the resistor, but that's how I shorted my coil and burned up my pretty new wires)

[zeiss150]

What does the ballast resistor look like?  Is that the white ceramic rectangle under the coil?  Or is it tiny cylinder with a wire coming out of it 🤷🏻‍♂️

[HuD 91gt]

Ceramic rectangle

[ZHoob2004]

Rectangle. The cylinder is your ignition condenser (capacitor), and that has its own functions (though how much function after 40 years I'm not sure)

 

http://atlanticz.ca/zclub/techtips/distributor/index.html

 

Important part is towards the bottom about removing the ballast resistor

 

Again, be aware the stock coil will not survive with constant 12v, and must be replaced with a unit rated for use without a resistor

 

This may not be your problem, you could just have a worn out coil, wires, cap, rotor, or ignition module causing weak spark

Edited November 10, 2017 by ZHoob2004

[Chickenman]

11 hours ago, zeiss150 said:

Well... I think I’m gonna build this turbo L28 and if it doesn’t work ... then I’ll welcome the 2jZ swap.  

I found a new problem today... intermittent spark 😡

i put a spark tester on my #1 cylinder and I got a very  intermittent spark.  I made a video but it wouldn’t upload. 

I have an electronic distributor from an 82ZX... so no points. 

And the coil is the original 72 240z coil. 

so let me state right up front ... I don’t know anything about electronics. 

I suppose it could be the coil so I’ll check that first tomorrow.  But if it’s not the coil then it would have to be the distributor ... right???

im gonna switch to ford edis anyway with my turbo mod so I guess I should do that first.  

Any suggestions or tips? 👍🏻

In the video... I think you simply have your spark gapping tool adjusted too far out I use these things all the time, and that is a huge gap.

 What spark leads are you running? If carbon core you could have a lead that has deteriorated and has higher resistance.  Carbon core wires are 1960's and 1970's technology. They have no place on a High Performance car these days. Never use solid core copper wire. Will cause a lot of electrical interference. 

NGK makes an excellent spiral core HT set for our cars for a very reasonable price ( Typically $19.95 online ) . Part number is NE61 ( SKU) or NGK8105 ( Item number ) . Available at any decent Auto Supply shop. MSD and Magnacore also make a very good spiral core wire. But a bt more expensive. 

Isee  you have the gapping tool hooked in series with your spark plug, condition of plug also comes into play.  And added to that you have the resistance of the plug gap ADDED to the resistance of the overly large testing gap. This is improper use of the Tool.  Normally I test spark output with a gapping tool by connecting the ground lead directly to a good engine ground, not to the spark plug That gives you a better indication of the True spark condition. 

You could also have a carbon trace inside the dizzy cap. Or the spark could actually be jumping to an adjacent plug terminal.  Electricity always takes the path of least resistance. Air is a very good insulator. A Carbon trace less so. 

 Coils don't go intermittent per cylinder. You have a good sharp spark. It is Blue and you can hear it snap. That's all good signs of a healthy coil and module.  Cut that spark tester gap down by at least half and connect it to an engine ground. 

 

Edited November 10, 2017 by Chickenman

[Chickenman]

You may want to check the dizzy cap and rotor now. By having such a large gap on the testing tool, combined with the plug gap... you could have created an Arc Over and carbon traces inside the dizzy cap or rotor.  Get a magnifying glass and look for Carbon Traces jumping form terminal to terminal or even to the base of the dizzy cap. They will look like hairline cracks or a line dean with a sharp pencil. Check the rotor as well. 

And also between the Coil center tower and the two primary terminals.  Arc over and carbon traces can form there as well.

Bottom line. You probably didn't have an INTERMITTANT spark. You had a spark that found a path of less resistance... and it went there instead of through the spark tester. 

[zeiss150]

this is the tester at the coil   The instruction on the package state that for HT spark it should be at 30.  Lawn mowers and weedwackers are 20.  

At some point I must have read a thread on how to bypass the ballist resistor because I did... I checked the voltage at the coil and I got about 5v  shouldn’t it be 12?  Or does it go in 5 and come out 12v.  I also check my battery and I’m getting 14.6v when running.  

The engine runs exactly the same with the spark tester on or off   It stumbles either way.   I think I’ve always had a spark issue but I’ve never looked into it.   

 

[HuD 91gt]

As Chickenman says, try it again grounded to an actual ground. Not at the plug. If no change,  Check the cap like he says.

 

 

Im only familiar with 240z wiring. But with the ZX modification you should have the ignition wire from the tach to the positiveon the coil. I do believe it should be 12v but look into it.  There should be a second wire running from the + of the coil to the ignition module. The other terminal on the module should go to the - of the coil.

 

Edited November 11, 2017 by HuD 91gt

[zeiss150]

I got some time today and I checked the voltage at the coil.  It’s 8 volts with the key in the on position (car not running)  and it fluctuates between 8 and 11.8 volts with the car running.   Does that seem right to you guys?  

I also made a video of the engine reving how does my engine sound to you guys. 

 

[Chickenman]

The instructions  for your plug gapper are are wrong. That's way too much of a gap. Period... end of story. Been using these things for over 40 years. 

That is a FRACKING strong spark!!!   Both appearance and noise show that secondary side is working damned good. It only appears intermittent because the spark has found an easier path to follow than through the HUGE gap of your spark tester combined with the gap from the plug. You are using the Tool wrong, and may have damaged other components ( such as inside of Dizzy cap and rotor ) by running such a huge gap when testing. 

BTW, have you checked your HT leads with an Ohm meter yet? . Those leads look like old style OEM carbon core. They deteriorate with age. Upgrade to some good quality spiral core wires such as NGK.  

 

Edit: Here is a video from Mac Tool showing the proper way to use a spark tester and the proper gap settings. Note that he mentions that the printed numbers on the tool basically mean dick squat. This is the same  Mac Tools spark Tester that I use. Also note that the maximum gap setting that the Technician opens it up to is about one third of what is shown in your video.

https://www.youtube.com/watch?v=YNIIllZRNRw

Edited November 15, 2017 by Chickenman

[zeiss150]

All the plug wires are “new”. Like 10 years old new. 

No damage from using the spark tester.  Cap and rotor are fine. 

Any thoughts on how my engine sounds?  

Also... anyone else notice the puff of smoke in the right upper corner of the screen?  What’s that about?

[Chickenman]

10 year old plug wires are not new. Especially carbon core wires. Wires can deteriorate just sitting. Ozone can crack and split boots. Then you can get arc over to engine. Corona discharge around plugs is also a problem with old leads. Plug leads should be checked with an Ohm meter. Just looking at them is not good enough. 

Pull your plugs and take some High Resolution close up pictures. use a good digital camera or a good Smart Phone camera. We need sharp clear pictures. Turn the flash off. It will skew the plug coloring. Try to get some good side on shots of the center ceramic and the full view of the side electrode. A Top angled view is best. How old are the plugs? 

Plug reading will tell you a lot about the engine running condition. 

I noticed the smoke. Sounds like you have an exhaust leak. Wouldn't surprise me if  you have a leak at the exhaust manifold. Check for loose or broken exhaust studs. Also any evidence of soot around exhaust manifold or cracks in exhaust manifold.

Engine sounds noisy. probably needs a valve adjustment .  If that has recently been done, then it could indicate that rocker arms are worn.  They will wear with a horizontal line across the wiping face. If you can feel the line with a finger nail dragged across the surface, then the rocker needs re-surfacing or replacement. No amount of adjustment will get rid of rocker noise when they get that worn.  But, I don't think that's your issue though. 

It's really hard to tell how an engine runs in a video. But in general, I think your car just needs a bit of a sharp Tuneup.  It doesn't sound all that bad. But loaded up on the road could be a different matter. Carb adjustment, carb balancing can work wonders on these engines. 

Also the distributor advance mechanism tends to seize up on these motors. Both mechanical and vacuum sides must be checked for free operation. The rotor should fit snug on the shaft. I've seen after market rotors that fit very loosely on the shaft. That's no good. You should be able to take the rotor and twist it about 20 degrees in the direction of rotation. Then quickly release it and it should " Snap " back to resting position. If it is hard to rotate or slowly returns or doesn't return all the way, time to take the dizzy apart and service it. You will have to clean and lubricate the mechanical Cam and governor weight system. 

Use a Vacuum pump to check Vacuum advance. Get the FSM specs and test it. Movement should be smooth. Hold vacuum and freely return when the vacuum release. The breaker plates have tiny ball bearing in them, and these ball bearing often rust or even fall out. 

Jason Grey's distributor page has a wealth of info:

http://newprotest.org/projects/510/jasonGrayDistributor.pl 

 

Here are specs for popular Z car dizzys in Excel format:

Distributor advance curves.xls

 

 

 

 

 

Edited November 16, 2017 by Chickenman