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My dizzy may be firing between posts - long and tedious reading


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I salvaged some dizzys over the years and have 1 that is complete,  I have noy got the engine in the truck yet but have studied the distributor to determine where #1 plug is located,


At TDC as the center (reluctor?) with 4 hump points pass by the stationary magnet also with 4 points that seem to build up a current then drop off abruptly due to the shape their shape my rotor button is precise;y between two distributor cap posts.


Has anyone ever seen this?  As stated I have not started the engine and do think it will run with this distributor because it ran with it before.


I always felt something wasn't quite right about setting my timing and burning up caps faster than normal. This distributor was put together with the best pieces of several old dizzys.



Is there a place on the internet that shows the internals and at what point they spark? If I disconnect the bottom plate I can turn the distributor enough that it looks like it may be firing right on a terminal but with the flat L shaped piece of steel with the 2 screws connected I don't have enough rotation for it to seemingly fire precisely on a plug terminal.



Does any of what I just typed make any sense at all.  I may have to hunt through years of junk to recheck my work on this dizzy, I do believe I have enough of the external transistorized box dizzy with the 1 magnetic pickup to use with an HEI configuration. Here is what I've got now...









This last picture is with the rotor lining up wyh the #1 terminal, but it doesn;t look like it would fire at this point.


I may be chasing my tail. I really need to get this thing installed so I can worry about something that actually is broken or not working. The next few days are supposed to be nice so maybe I can get this shit worked out.

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This is what a matchbox distributor looks like when it is firing a plug.



I had to put a matchbox distributor on a L-16 pedistal, modify the plate between the distributor, and pedistal, and drop the oil pump, and distributor drive spindle to get it to line up.



This is how I set it up.  I put the engine at 10 to 12 degrees before TDC, #1 by rotating the engine clockwise.  Do not go too far, and back up.  Stop at 10 to 12 rotating clockwise on the crank pulley.

I chose this tower for the number one spark plug.


I turned the distributor rotor to point at that spot on the distributor body, AND have the points on the rotor and stator (pickup) line up in the distributor.  Then I turned the distributor over, and looked at how the drive spindle would have to be set to match the distributor.  I dropped the oil pump, along with the drive spindle, and turned the spindle away from the stock location, and put the pump and spindle back in.  


There are two bolts on the plate between the distributor, and pedastal.  I centered the plate on the pedastal, and bolted that together.  Then I set the initial timing by leaving the bolt on the underside of the distributor loose, and adjusting the body of the distributor to line up exactly the points on the rotor and pickup, and then tightened the plate to distributor bolt.

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Pull coil center wire off and hold near ground. Crank motor. If you have a spark you're good. Now all you have to do is get the cap wires lined up.




Set TDC #1

Remove dizzy and look in the hole...


This what you should see...



NOTE: there is a large and small 'half moon'. Small goes to the front. If you are between plug wires the drive spindle may not be oriented properly as in the above picture.

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at TDC your spindal is in the famous 11/28 postion.

Now drop the dizzy in the pedastal and where it locks down is your #1 position.. Your timming plate should be close to the center of the R and A(advance) and have roome to move it.


it its in between number 1 & 3 at TDC you got the wrong pedastal. as they were 2 types. So I assmume you been grabbing set and mismatched it. alwasy brab the pedastal mount with the dizzy.


if you dont have the correct padastal one has to drop the oil pump and move the spindal 1 tooth and reinstall so it come out on #1 plug wire.


OK again

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if you dont have the correct padastal one has to drop the oil pump and move the spindal 1 tooth and reinstall so it come out on #1 plug wire.




Does that look right? It's dead on TDC compression stroke,  If by chance I were to move it what harm befouls me other than my distributor button points at a different terminal than the book says it should?


I do not want to experiment with turning the oil pump once I get the motor installed. I do think it's possible the dizzy has mismatched parts.


But again this is the distributor I was running with, just bought too many caps and buttons for it with a burn spot at the edge of the rotor button about every time.

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Looks just fine but when dizzy installed, is the rotor pointing to any wire on the cap? If half way between two, you may have to drop the oil pump and the drive spindle and turn it a couple of teeth to rotate the rotor to the next wire on the cap. Other than the correct pedistal this is what you will have to do.


It's normal for the rotor end to have a burnt pitted look as long as it's not eroded away. Same with the terminals inside the cap. Brass ones are the best but many today are aluminum.

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there were 2 types of matchboxes dizzy .the pedastal are made for one or the other.


. I do think it's possible the dizzy has mismatched parts.

But again this is the distributor I was running with.


maybe the oil spindal was installed off a tooth before you took it apart and now you put it per the manual only to find out maybe it was retimmed for the mismatched set up you have.


dont be a pussy you can drop the oil pump anytime. We do it in in the parking lot. Just have some rags and dont let the oil out of the pump.

alway have motor at TDC as your referenace

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I see exactly what he's talking about...


Looks like you have the wrong reluctor? (Center magnet) the distributor. Look in Daniels photo how the flat on the shaft lines up between the points, and your flat side (where the roll pin is) is on the point.

You got me thinking.....check this out....






With another star wheel /reluctor from the grab bag of extra parts it's easy to tell one is gonna spark about half advanced or retarded from the other.


While I've never been exactly satisfied with my oil pump drive pin location, it is [retty close and if advanced or retarded just one groove it really looks far off I'm gonna call the oil pump shaft tang OK as is.


Looking at these two reluctors that fit in the distributor it's easty to tell if mixed up you are gonna fire between spark plug posts if you use the wrong one.


By the way one has an R stamped on it, the other has an L stamped on it.  Don;t mean anything to me but I'm gonna change them out and call this thread a success until further notice.

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"alway have motor at TDC as your referenace"


This is true, most of the time, in fact, almost always it is true.


But there are a few exceptions.  One exception is when you mix and match distributors, pedestals, and timing plates, from different engines, like a early L-16 using a late L-20-B distributor, and do not have the proper pedestal, or timing plate.

(Timing plate- the plate between the distributor, and pedestal, that holds the distributor in the proper location.)


I would suggest when assembling the engine, installing the camshaft, or replacing the head, the engine must be exactly at TDC.  If you have all the original parts that came with that engine from the factory, Including the distributor, timing plate, and pedastal, you can install the distributor, oil pump, and distributor drive spindle with the engine at exactly TDC.  Set it up like the factory service manual says. Or Mike's excellent video.


However, if when setting up an engine, with parts, and distributors from different years, or engines, you end up with the rotor pointing between two spark plug towers, I suggest you put the engine at exactly TDC for all the assembly step, until it is time to set the distributor on the engine.  In this case, I suggest you set the engine to 10 to 12 degrees before TDC, #1, by rotating the engine forward.  Then install the distributor, and if the rotor does not point at a spark plug tower on the distributor, dropping the oil pump, and drive spindle is a way to make the distributor rotor point to a tower.


Post 25, on this page of my project thread, shows me setting up a matchbox distributor on a L-16, witht he mismatched parts.


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I can only find one part number for all the L20B matchbox reluctor sets. The matchbox was only used in '79 and the '80 720 for one year. The A series matchbox can be retro fitted to work on an L series so maybe it has an A series reluctor???


'79 200sx

'79 A10

'79 620

'80 720......................... 22115-W5800... L20B

'79- and up 210/310...... 22115-H9100.... A series

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like I said before there were 2 types of matchboxes. so there are 2 type of pedastals. the tang that stick out to hold the dizzy tight is positioned off thus putting the rotor in the wrong spot. Its enought to get started but once you get going it goes out of time.

I had these side by side that How I know and I think its in the Oldatsuns.com the tech section with Jason gray write up.

Its a simple fix whatever what you do this

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