How to test if this is the correct coil?

[Primerdimer]

So I see everyone saying to make sure the correct coil is used, especially on stock setups,  but I can’t find anywhere that shows what specs I need. I have a 72 521 with a dual points distributor (I know, I really want the EI dizzy). I’m having a hesitation issue happening and trying to narrow things down starting with the spark plugs, cap, rotor and now the coil. Trying to make sure everything is working correctly before moving onto valve lashing, timing, and carb...

 

anyways, just wanted to know how much resistance I should be looking for my particular setup. Thanks a lot 

[datzenmike]

ALL points systems are limited by the current the points can handle. They can conduct about 4-5 amps. More and they simply wear out from arcing and need to be replaced too often. Thus a 1.3 to 1.5 ohm primary resistance, plus a ballast of 1.5 ohms drops it to a manageable amount. The EI dizzy uses high power handling transistors so no arcing to worry about. The EI coil has a primary resistance of .8 to 1.0 ohms and no ballast. This would allow 12 to 15 amps through the coil producing a much hotter higher voltage spark. Gap points to 0.020"

 

Plugs are NGK B6ES gaped to 0.032"

 

Cap and rotor are still available and get good quality plug wires. NGK if you can.

 

Set carburetor idle adjustments last.

 

Set valves hot at 0.010" intake and 0.012" exhaust. By using the following method you can set them fast enough that the engine does not cool down before finished. 

 

Warm engine.

Set to TDC compression stroke #1. Does not have to be exact just close enough that the #1 valves are closed.

Set the following valves..

Both on #1

Intake on #2

Exhaust on #3

Turn engine ONE turn and up to TDC and set the remaining valves...

Exhaust on #2

Intake on #3

Both on #4 ....done. This avoids bumping the starter over and over and over.

 

Timing is 12⁰ engine must be capable of an 800 rpm idle to set this. Too fast and mechanical advance will kick in and upset it.

 

Idle mixture and speed.

Turn idle down to 600-700 or low as possible using the idle speed screw. Turn idle mix screw in or out to achieve the fastest smooth running. Try 1/8 or 1/4 turns with several seconds to allow the new setting to settle down. Too far in or too far out and the idle quality drops off and there will be 1/2 or more turn where there is no change, just set roughly in the middle Turn idle speed back down and repeat. It may take a half dozen repeats to get it right. Continue until you cannot improve the idle quality any more and the idle speed is 750-850.

[banzai510(hainz)]

I think your fine on your set up. Since it’s dual points maybe that has to be adjusted correctly and the timing. Say 10-12 btdc try this first. When you get time check the valve lash just by making sure the cam lobe is up and wiggle the rocker and if loose then the valve is closing.Be honest I never was good at adjusting the dwell. If this happens in 3rd gear then look at the points.

maybe you carb accel pump is wearing out.

or is this a Weber carb and the hesitation is between the 2rd barrel opening which is normal is one steps on gas to fast.

[Primerdimer]

Thanks so much, just what I was looking for! 🙏

[mklotz70]

There's several places online to download the manuals....but here's one place I know of off hand. lol

 

http://www.bluehandsinc.com/manuals.html

 

If you have a Weber carb, follow it's directions closely.  The primary goal when adjusting the weber is to have the throttle closed as much as possible.  If it's open, even slightly more than it should be, it will uncover the vac advance line.  You'll get no change in the vac signal so you'll end up with no vac advance, which causes bad hesitation.  You'll also want to make sure that you have the vac advance line disconnected and plugged while setting the carb and the timing.  The factory Hitachi is a great carb as long as the bushings for the throttle shaft aren't worn out and leaking air.  They're easier to tune and I've always gotten better throttle response from them.......but....the webers tend to be better for the highway and get better gas mileage.  

 

The manual should have a cold setting for the valve adjustment.  Doing it hot is best, but if you're not familiar with it, you can set them cold.  I did this vid a really long time ago....it might help give you an idea what you're in for on a valve adjustment.  

 

The dual points dizzy you have is not truly a dual points dizzy.  The second set is only for emissions.  A true dual point will use both points in parallel to handle higher current and the points will be exactly 180deg from each other so that they open/close at exactly the same time.  Make sure that you adjust the primary set of points.  The emissions set can be removed.  The manual will explain when the second set it used.......third gear while decelerating.....or something like that.  

 

There are a couple of options out there instead of the EI dizzy.....although the matchbox EI dizzy is the best.  Pertronix units are probably still around.  You can use a GM HEI ingnition unit with your points and there's a version of the matchbox dizzy that has a remote igniter.  As Mike explained earlier....the EI and points coils are different.  The points coil actually has the resistance built in, but a lot more windings to give a hotter spark.  The points dizzy has an external resistor so that it can be bypassed while the engine is cranking.  The starter pulls the volts down a lot while turning, so the resistor is bypassed to help give a hotter spark when starting.

 

 

 

Edited November 18, 2019 by mklotz70

[Stoffregen Motorsports]

17 hours ago, banzai510(hainz) said:

or is this a Weber carb and the hesitation is between the 2rd barrel opening which is normal is one steps on gas to fast.

The early DGV had an issue with this hesitation, but later carbs stamped "5A" have an improved fuel circuit to cure that hesitation.

[Primerdimer]

Ok, so I’ve changed my points, and checked/set the gap on them. Put in new ngk B6ES plugs gapped to .032 along with ngk wires. New cap and rotor. Didnt touch the coil or condenser yet (but will) and the problem was fixed, runs great.
So I moved on to adjusting the valve clearances and they all needed adjusting. Runs even better afterwards, with less clatter noise. 
I’m focusing on ignition timing and carb now. My problem is that I’m getting different info from different sources. One thing I’m reading (Clymer) says “the grooves(on the crank pulley) are graduated I’m 5 degree increments. The TDC mark is to the EXTREME-LEFT of the engine as viewed from the front” and “specs for timing requires timing at 10 degrees BTDC, which would be the 4th mark from the left” ??—4 marks in 5 degree increments, isn’t that 20 degrees BTDC??

ALSO, in the L-series engine manual from Nissan, it says that TDC is located to the extreme right... so now I don’t know which side is which... 

 

Can someone shed some light for me here? Thanks a lot!

[datzenmike]

'72 521 L16

 

There were different crank pulleys and timing pointers used on different L series engines. Yours is probably a pointer on the left (driver's) side and the crank pulley has small notches in it. As to turns clockwise the first notch will be the most advanced and the last one (on the far left as viewed from the front) would be TDC top dead center.

 

Try 4 notches and if you are right it will ping like crazy. May even be hard to start.

 

 Then try 2 notches. That should be 10⁰.

 

 

 

 

 

On 1/6/2011 at 2:55 PM, banzai510(hainz) said:

L16s use a pointer on the front cover and the 5 marks on the pulley.

 

the most left groove is Zero and every grove is 5 deg up to 20deg.

 

 

[Primerdimer]

1 hour ago, datzenmike said:

'72 521 L16

 

There were different crank pulleys and timing pointers used on different L series engines. Yours is probably a pointer on the left (driver's) side and the crank pulley has small notches in it. As to turns clockwise the first notch will be the most advanced and the last one (on the far left as viewed from the front) would be TDC top dead center.

 

Thanks, the pointer is on the passenger side for mine, any info on that?

[datzenmike]

Same applies just the side changes.

[mainer311]

Also, and you might want to experiment a little bit with this, but these trucks run so much better with more than 10 degrees advance. 12-15 seems to work a hell of a lot better.

[datzenmike]

The '73 620's L16 says 10^o but L20B is 12^o. Maybe because the L16 has an 8.59 compression and the L20B is 8.4?? 

[mainer311]

That’s possible I suppose. 

[datzenmike]

I would think they would all be 12^o.

[mainer311]

Probably emissions related. My Roadster (with smog pump) was timed at 0 from the factory, with 32 degrees mechanical. The popular thing to do was de-smog them and recurve the dizzy. Ran so much better after that. 16 degrees at idle and 16 mechanical.

[datzenmike]

Probably it.