Distributor Help

[510_dreamin]

I currently have an L20b with a matchbox distributor, and after replacing the matchbox noticed it starts to miss when revving and has no power. There is a spark coming out of the base of the distributor at times. It is also fouling plugs very quickly. 
 

Any suggestions on how I can troubleshoot this?

 

If I need a new distributor are there alternatives to a matchbox style as those seem pretty expensive and hard to find 

[datzenmike]

1 hour ago, 510_dreamin said:

 There is a spark coming out of the base of the distributor at times. It is also fouling plugs very quickly. 
 

 

 

You mean the base of the distributor cap????  Try a new distributor cap and rotor

 

If the actual base of the distributor, tighten the bolts holding it down to the timing cover. The distributor needs really good ground. Some matchbox distributors have a special ground lug just for grounding it.

[yenpit]

Since Matchbox dizzy's are getting harder to find (don't think RockAuto has any more??), we have moved to the earlier mag pick up style with a remote amplifier box.  The factory remote amp box is like a big ass ECU, so we do NOT use those!  We use the Chevy HEI amp box (small) along with the correct finned aluminum "base", which allows the amp box to remain cool.  Easy wiring is available online.  You can also use an MSD ignition box.  Another great alternative, however very expensive, is the 123distributor.com fully adjustable electronic dizzy assembly.

[510_dreamin]

23 hours ago, datzenmike said:

 

You mean the base of the distributor cap????  Try a new distributor cap and rotor

 

If the actual base of the distributor, tighten the bolts holding it down to the timing cover. The distributor needs really good ground. Some matchbox distributors have a special ground lug just for grounding it.

how would I know if it has a lug, or how else would it be ground? 

[510_dreamin]

9 hours ago, yenpit said:

Since Matchbox dizzy's are getting harder to find (don't think RockAuto has any more??), we have moved to the earlier mag pick up style with a remote amplifier box.  The factory remote amp box is like a big ass ECU, so we do NOT use those!  We use the Chevy HEI amp box (small) along with the correct finned aluminum "base", which allows the amp box to remain cool.  Easy wiring is available online.  You can also use an MSD ignition box.  Another great alternative, however very expensive, is the 123distributor.com fully adjustable electronic dizzy assembly.

many links or more info about the alternate setups?

how would an msd box work with an L20?

[datzenmike]

Why did you replace the matchbox???? What was it doing or not doing? If this didn't change anything it's probably not the matchbox. The matchbox is grounded to the distributor case by the two mounting screws. The distributor is grounded through the two mounting bolts. It's cheaper and easier to tighten them.

 

This is what you have? Not all matchbox EIs have a dedicated ground. Here it's near the forefinger. Brass lug with screw through it.

 

 

 

 

[510_dreamin]

I replaced the matchbox as one of the tabs broke. 
 

What it’s doing now is the car is missing/has almost no power. Prior to the matchbox breaking it ran great. 

 

[datzenmike]

Then it would seem that the 'new' matchbox is bad if it ran fine before. Cheapest good fix is an HEI module from a older GM car or truck. As little as $10-$25 or if in a wrecking yard they fit perfectly into back pocket...

 

 

 

Ignore the 'Non Matchbox' and the 1.6 ohm coil.

You need a 0.8 to 1.0 ohm EI coil (you probably have one) Should say 12v on it. HEI must be well grounded. If fails to spark reverse the W and the G.

 

[datzenmike]

Does the new module say E12-80?

 

 

Or E12-93

 

[510_dreamin]

Here is the one I am using:

 

https://www.oreillyauto.com/detail/c/import-direct-ignition/import-direct-4-terminal-ignition-control-module/odi1/140107/v/a/8235/automotive-truck-1979-nissan-620-pickup?q=Ignition+module&pos=0

 

 

[datzenmike]

Generic  but has correct number of terminals. It's not the wrong one.

 

So where are the sparks coming out of the bottom????

[yenpit]

On 12/7/2021 at 10:47 PM, datzenmike said:

Then it would seem that the 'new' matchbox is bad if it ran fine before. Cheapest good fix is an HEI module from a older GM car or truck. As little as $10-$25 or if in a wrecking yard they fit perfectly into back pocket...

 

 

 

Ignore the 'Non Matchbox' and the 1.6 ohm coil.

You need a 0.8 to 1.0 ohm EI coil (you probably have one) Should say 12v on it. HEI must be well grounded. If fails to spark reverse the W and the G.

 

 

Yes, that is the HEI set up!  We tend to avoid all made in China/Taiwan etc parts like this HEI amplifier.........but we MUST have reliability on the race track, or we LOSE!  We like the quality of the HEI amplifier sold by MSD (could still be made in China (??), but looks like a better product & we have not had any failures.  This one in the pic has what looks like a homemade aluminum "base", which prolly works fine, but GM offers a nice "base" aka as a "heat sink".

 

[yenpit]

On 12/7/2021 at 9:08 PM, 510_dreamin said:

many links or more info about the alternate setups?

how would an msd box work with an L20?

 

Really, any good aftermarket electronic ignition system will work, but MSD has always been one of the most popular.  You will need a good solid basic understanding of mechanical (to install) & electrical (to wire up).  Sorry, I'm not good at posting links, but there is lots of info online!!

 

[datzenmike]

This is why I suggested one from a wrecking yard. An original GM part.

[iceman510]

Back when we started racing in the 80's, we had a Cosworth Vega that had a miss.  We replaced the HEI module and the problem persisted.  Couldn't find anything else wrong with fuel, vacuum, etc, so we took it to a shop to try to find the issue.  Shop replaced the HEI module and low and behold it worked fine.  So the new one we bought (aftermarket from someplace like Autozone-but pre-Autozone at least by me) originally was bad too.  Moral of the story, the new part may be NG. 

 

TJ's suggestion and Mike's suggestion to stay with an OEM part or a company with a good reputation is sound.  May not be possible to get an OE Nissan module, but perhaps the one from O'Reilly is no good.

[datzenmike]

I definitely don't recommend auto parts store parts. 

[510_dreamin]

Can you suggest what years I should look for a GM HEI module? A new OEM matchbox is quite pricey and almost seems at $150 for the part maybe a new set up might be a better idea? 

 

Question on the matchbox. Does the negative wire from the matchbox go to ground or to the coil?

[datzenmike]

If the matchbox has a ground lug, run the wire from it to a ground on the block. It's just an add on insurance as the mounting bolts are what it normally grounds through. You don't want to ground to the coil as the matchbox turns the ground on and off to fire it.

 

HEI was used for about 10 years from 1975 through the mid-1980s but you want the 4 pin type and they were only on carbureted engines up till the late '70s.

[510_dreamin]

My black wire coming off the matchbox on the top horizontal lug is ground to a bolt on the radiator. 
 

could that be the issue possibly?

[datzenmike]

Ground it to something on the block. The ground cable from the battery is bolted to the side of the head behind the water pump so the block is a shorter path. The extra ground is just insurance, they ground through the distributor mounting bolts. My matchbox does not have a separate ground wire and it works just fine.