Distributor Question for 79 FJ40 (electronic, small cap)

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Joined
Feb 23, 2024
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258
Location
Idaho
I've been struggling for a while with the stock distributor on my 79 FJ40 project that had been sitting for over a decade and abused before that.

I got the distributor freed up and cleaned up, so that it started and seemed to run ok, but always a bit rough. In the process of cleaning I noticed a small amount of slop in the distributor shaft, coinciding with the mating to the cam gear. It seems the bushing may be slightly oval-shaped in that direction. A member here suggested that slop would be fine. Just adjust the air gap on my pickup accordingly, which I did and it ran, albeit roughly.

Today I dug a bit deeper and discovered I had no spark on #5 cylinder due to a distributor issue. When I opened the well-used cap I saw this -
20250219_143901.jpg



Looks weird, right? Seems like a lot of carbon for only a few hours use.

The no-spark cylinder, #5 is at 11 o'clock. Notice the carbon at the top and bottom of the screen and clean terminals at either side. This seems to correspond to the distributor shaft slop top-to-bottom, and it being tight side-to-side.

BTW, that oem cap came with the vehicle and is very used and poorly repaired. There were previous carbon traces and gouges from an aftermarket rotor. I have one clean aftermarket cap and rotor, but don't want to use it until I get the bushing slop eliminated, because these caps and distributors were only used on two model years (79 and 80) and have become a bit rare.

So, my options seem to be:

- Replace the bushing on my oem 79 distributor. Any recommendations on who might do this?

- Substitute a cheap aftermarket electronic distributor. I have one on the shelf, but don't want to use it because it's not water resistant. However that's probably my next step in the short term just to get my 79 running properly.

- Upgrade to a big cap distributor and dimpled pushrod cover from a later FJ40 or FJ60. This is my preference long term. I just put up a new classified ad looking for one. Let me know if you've got one laying around.


One more thing I'm wondering about is, does that excessive carbon buildup in the cap indicate any other ignition issues? I'm using the stock coil, igniter with Yazaki ignition wire, and have rewired some of the ignition circuit to hopefully match the schematic.

However, today I checked voltages on the primary and got 7v with the ignition switch on, around 10v while cranking and a little over 12v while running. I was thinking the primary voltage should drop back to 7v when running to improve the life of the coil and reduce arcing? Is that 12v contributing to the arcing in the cap? If so, where should I look to correct this?

Any suggestions on any of this?
 
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Interesting. That carbon dust is conductive and could allow the spark to jump to other plugs - that could make it run ruff.
Hardly any dizzy is water proof, so I would let that stop me unless your rig has a functional snorkel and you use it.

As soon as the ice and snow is gone I'll be making a new bushing for my delco distributor. I could buy a china repo for like $80 complete cap, points ... on Amoron. I just need to swap in my drive gear if that the way I have to go. I will also be doing the Rochester carb with the ultrasonic and its carb juice. Neither have really been touched since the rig came that way in 82. Amoron has the china carb for around $100 last I looked.

Not being a purest has some $ advantages. The fuel pump/filter was a 1 year only 72. When the pump died I threw it away and went to an electric fuel pump. I spent $$$ on the first one and it lasted a good while. When it died I cut open the can crimp to discover one of the brushes was hung up in the holder. A little file work allowed it move freely. So I Aviation Permatex the rubber gasket on both sides and pounded the can crimp seal back in place. That was around 1990. It finally died again 2005. Then I bought a cheap Autozone $$ pump and it only lasted a few years. Next I got a cheap Diode pump like $10. They last a decade or more.

I use them to make my fuel transfer device. It attaches to the battery or cig lighter. Filtered, fused, and water proof switch on like a 12' power cord. Suction line is 5' and has a 20' delivery hose. Was about $50 to make. Way better than holding up 5 gallon cans of gas. It will also do diesel.

PICT0075.JPG
 
Interesting. That carbon dust is conductive and could allow the spark to jump to other plugs - that could make it run ruff.
Hardly any dizzy is water proof, so I would let that stop me unless your rig has a functional snorkel and you use it.

As soon as the ice and snow is gone I'll be making a new bushing for my delco distributor. I could buy a china repo for like $80 complete cap, points ... on Amoron. I just need to swap in my drive gear if that the way I have to go. I will also be doing the Rochester carb with the ultrasonic and its carb juice. Neither have really been touched since the rig came that way in 82. Amoron has the china carb for around $100 last I looked.

Not being a purest has some $ advantages. The fuel pump/filter was a 1 year only 72. When the pump died I threw it away and went to an electric fuel pump. I spent $$$ on the first one and it lasted a good while. When it died I cut open the can crimp to discover one of the brushes was hung up in the holder. A little file work allowed it move freely. So I Aviation Permatex the rubber gasket on both sides and pounded the can crimp seal back in place. That was around 1990. It finally died again 2005. Then I bought a cheap Autozone $$ pump and it only lasted a few years. Next I got a cheap Diode pump like $10. They last a decade or more.

I use them to make my fuel transfer device. It attaches to the battery or cig lighter. Filtered, fused, and water proof switch on like a 12' power cord. Suction line is 5' and has a 20' delivery hose. Was about $50 to make. Way better than holding up 5 gallon cans of gas. It will also do diesel.

View attachment 3842805
Yeah, I've been in budget mode with my 79 project too. It's amazing what you can do with a little cleaning and creativity to repurpose old, nasty parts.

About the distributor choices, I have read lots of good things about that big cap distributor from the FJ60, including its use of a bearing, as opposed to the bushing on the older distributors. Since the bushing seems to be worn on my original distributor, the extra life a bearing could offer seems desirable.

And no, I don't run a snorkel (yet), but we do get some weather up here in Northern Idaho and lots of gravel roads and dust that could be a problem for a cheap distributor. That o-ring at the base is a nice feature on oem.

But, in the interim I'll probably just use that cheap aftermarket distributor from Amoron as you called it that I picked up as a spare. Looking forward to running on all 6 cylinders!

Before that though, I kinda need to sort out that issue of a higher voltage on the primary (12v vs 7v) so I don't ruin the new distributor, whatever that may be.
 
I never pressed-out the pin that holds the gear to the distributor housing. I understand the drawing as the governor shaft goes into the distributor housing. Maybe someone can sleeve the dizzy housing for a tighter fit?

However, if the distributor is really spinning a loose shaft, you should question how much cam strain is being placed on the cam gear. The gear needs to be supported by the oil pump and the distributor housing. Generally, you replace (worn) precision surface-contact parts like bearing-races in pairs, and because gears are super precise (like a differential ring gear) a worn pinon will eventually 'grenade' a cam gear, or a worn cam gear will 'grenade' a distributor gear. (In shop theory.) This oil-pump gear has quite a bit of resistance pushing modified candle wax thru a winter-cold rocker assembly, so the distributor has an important role in keeping these teeth meshed properly. You might want to do a visual inspection on the distributor gear before you commit you distributor to a rebuild.

City Racer has a couple new OEM distributors. I'd save the frugal hacks for something not part-supported, like a Willy's Hurricane; an FJ40 is all about the love and support that we can continue to enjoy from the manufacturer.
 
I never pressed-out the pin that holds the gear to the distributor housing. I understand the drawing as the governor shaft goes into the distributor housing. Maybe someone can sleeve the dizzy housing for a tighter fit?

However, if the distributor is really spinning a loose shaft, you should question how much cam strain is being placed on the cam gear. The gear needs to be supported by the oil pump and the distributor housing. Generally, you replace (worn) precision surface-contact parts like bearing-races in pairs, and because gears are super precise (like a differential ring gear) a worn pinon will eventually 'grenade' a cam gear, or a worn cam gear will 'grenade' a distributor gear. (In shop theory.) This oil-pump gear has quite a bit of resistance pushing modified candle wax thru a winter-cold rocker assembly, so the distributor has an important role in keeping these teeth meshed properly. You might want to do a visual inspection on the distributor gear before you commit you distributor to a rebuild.

City Racer has a couple new OEM distributors. I'd save the frugal hacks for something not part-supported, like a Willy's Hurricane; an FJ40 is all about the love and support that we can continue to enjoy from the manufacturer.
Thanks for the info and suggestions.

When I had previously pulled the, what looks like the original oem electronic distributor to free it and clean it, I did a visual inspection on its gear and oil pump drive as well as what I could see of their mating gears inside the the engine.

At the time, I was concerned about the oil pump delivering sufficient oil to the rocker assembly, which I had also freed and cleaned after years of sitting. All seemed ok at the time, except for the slightly noticeable slop in one direction in what seemed like the distributor shaft bushing. I reached out to a knowledgeable member here who said, based on my description, it should be fine since it was an electronic distributor.

Here's the only pic I have showing the distributor gear from that time.
Screenshot_20250220_072148.jpg

The distributor slop doesn't feel any worse now, so hopefully no damage has been done internally. But, I'll make sure to look it all over very carefully when I pull the distributor. A lot rides on that bit of gearing!

About what to do with the offending distributor, I had read somewhere that there was a brass bushing inside that could be replaced, but that would have shown up on your drawing, right? I may try to find a local machine shop that can do the work, either bushing replacement or sleeving as you suggested, if I opt to reuse it.

Still pondering the best electronic distributor replacement longer term. I like City Racer products, but his distributors are points only. I would still prefer a serviceable big cap oem electronic distributor if I can find one.

But in the short term, I'll probably be pulling that aftermarket electronic distributor off the shelf to get my 79 running again and continue my tuning efforts. Hopefully firing on all 6 cylinders will make a difference!
 
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I never pressed-out the pin that holds the gear to the distributor housing. I understand the drawing as the governor shaft goes into the distributor housing. Maybe someone can sleeve the dizzy housing for a tighter fit?

However, if the distributor is really spinning a loose shaft, you should question how much cam strain is being placed on the cam gear. The gear needs to be supported by the oil pump and the distributor housing. Generally, you replace (worn) precision surface-contact parts like bearing-races in pairs, and because gears are super precise (like a differential ring gear) a worn pinon will eventually 'grenade' a cam gear, or a worn cam gear will 'grenade' a distributor gear. (In shop theory.) This oil-pump gear has quite a bit of resistance pushing modified candle wax thru a winter-cold rocker assembly, so the distributor has an important role in keeping these teeth meshed properly. You might want to do a visual inspection on the distributor gear before you commit you distributor to a rebuild.

City Racer has a couple new OEM distributors. I'd save the frugal hacks for something not part-supported, like a Willy's Hurricane; an FJ40 is all about the love and support that we can continue to enjoy from the manufacturer.
Well put, and almost poetic!
 
So, my options seem to be:
Alternatively, you could ask around and see if anybody has an old one in the bottom of their spare dizzy milkcrate that they're never going to use.

20250220_083336.jpg


20250220_083349.jpg


20250220_083407.jpg


20250220_083432.jpg
 
I've been struggling for a while with the stock distributor on my 79 FJ40 project that had been sitting for over a decade and abused before that.

I got the distributor freed up and cleaned up, so that it started and seemed to run ok, but always a bit rough. In the process of cleaning I noticed a small amount of slop in the distributor shaft, coinciding with the mating to the cam gear. It seems the bushing may be slightly oval-shaped in that direction. A member here suggested that slop would be fine. Just adjust the air gap on my pickup accordingly, which I did and it ran, albeit roughly.

Today I dug a bit deeper and discovered I had no spark on #5 cylinder due to a distributor issue. When I opened the well-used cap I saw this -
View attachment 3842639


Looks weird, right? Seems like a lot of carbon for only a few hours use.

The no-spark cylinder, #5 is at 11 o'clock. Notice the carbon at the top and bottom of the screen and clean terminals at either side. This seems to correspond to the distributor shaft slop top-to-bottom, and it being tight side-to-side.

BTW, that oem cap came with the vehicle and is very used and poorly repaired. There were previous carbon traces and gouges from an aftermarket rotor. I have one clean aftermarket cap and rotor, but don't want to use it until I get the bushing slop eliminated, because these caps and distributors were only used on two model years (79 and 80) and have become a bit rare.

So, my options seem to be:

- Replace the bushing on my oem 79 distributor. Any recommendations on who might do this?

- Substitute a cheap aftermarket electronic distributor. I have one on the shelf, but don't want to use it because it's not water resistant. However that's probably my next step in the short term just to get my 79 running properly.

- Upgrade to a big cap distributor and dimpled pushrod cover from a later FJ40 or FJ60. This is my preference long term. I just put up a new classified ad looking for one. Let me know if you've got one laying around.


One more thing I'm wondering about is, does that excessive carbon buildup in the cap indicate any other ignition issues? I'm using the stock coil, igniter with Yazaki ignition wire, and have rewired some of the ignition circuit to hopefully match the schematic.

However, today I checked voltages on the primary and got 7v with the ignition switch on, around 10v while cranking and a little over 12v while running. I was thinking the primary voltage should drop back to 7v when running to improve the life of the coil and reduce arcing? Is that 12v contributing to the arcing in the cap? If so, where should I look to correct this?

Any suggestions on any of this?




there is 1 much bigger issue here you need to know above all other mechanical ones related to your existing Distributor above


it's been mote then a year+ maybe close to 2 years now that TOYOTA Disc. / NLA the
19101-61100 / 19101-61101 aka Triangle 3-screw Med. Cap

this fact alone makes any 19100-61091 USA & CANADA spec. only Distributor assy. a obsolete part , or a parts unit if a Cap 19101- is ever needed ....?


.

- 19100-61092 8/80 - 9/81 Canada Spec. only FJ40 & FJ60
( NOTE : FJ60 was a single model year in CANADA in 1980 , it was too snow-version for it & could not hang ) ....... :D
BJ60 was there 8/80- Later also , & HJ60 came in 10/85 -9/87 to pick up the slack of the poor little
3B with the mighty 2H

- 19100-61091 10/77 - 8/80 USA-Spec.

i have yet to see a aftermarket cap surface after TOYOTA disc. / NLA the short lived
19101-61101 superseded new Black color one with the maroon air-flow suction hose / vacuum ports ....


that's all i know .....

if anybody knows different ? please post below , this is a current update tech. info as of .....today .....


matt
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1740074803689.jpeg

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1740074610534.png
 
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OP, I have the same unicorn dizzy in my 79. It looks like your bushing is shot. Buy a large cap FJ60 along with the coil and ignitor setup before those are gone. I noticed used have really jumped in price. Otherwise go HEI like the DUI aftermarket.
 
OP, I have the same unicorn dizzy in my 79. It looks like your bushing is shot. Buy a large cap FJ60 along with the coil and ignitor setup before those are gone. I noticed used have really jumped in price. Otherwise go HEI like the DUI aftermarket.
Yeah, that's my plan, that is if I can find a large cap distributor (and dimpled pushrod cover). Hopefully my "Wanted" ad on IH8MUD will help.

I was thinking I could use my existing igniter and coil with it, but with so much arcing in my current setup, maybe I shouldn't trust it either?
 
OP, I have the same unicorn dizzy in my 79. It looks like your bushing is shot. Buy a large cap FJ60 along with the coil and ignitor setup before those are gone. I noticed used have really jumped in price. Otherwise go HEI like the DUI aftermarket.

That's what I did, and it has worked really well for me. The big-cap 60 dizzy runs on bearings, instead of the bronze bushings in the earlier ones.
 
Ha! Sounds like you may know such a person or have such a milk crate?
Yup. It's always good to have a spare or two and a project or two. I am never going to use that dizzy, especially if I can't get a cap for it.
I like the earlier OEM vacuum advance dizzys. I'm running a '76ish non-Ca dizzy now but I need to refurbish one of my '69-Earlier with the little brass oiler thing, I really like those.

20250220_094919.jpg
 
I just went thru my stash. One has never been used. The other will turn 50-years-old in April, minus the rebuild. Both have end-thrust-play (spec. is .006 to .020-inch), and, both have just negligible rotor-axial-slop.

20250220_120314.jpg


The '75 unit clearly has some wear on the gear, and varnish visible on the governor shaft thru the oiling hole. I went thru it a few years ago, but, I probably should have used high-temp-brake-parts grease on the centrifugal advance, and points-set-cam. For me, it is all about those springs registering the correct centrifugal advance curve. This isn't a realistic expectation (my subjective opinion) out of a rusty antique distributor, but, it certainly is with the never-used one that patiently waits on the shelf with the black cap and rotor. I could probably modify either one to electronic, but, the semi-electronic points igniter that came with the replacement engine still functions, so, I'm not running the points as hard.
 
I've got lead on a large cap FJ60 distributor upgrade, which I may prefer at this point for reliability and serviceability reasons,
That would be a desirable end result. I understand they can be hard to find and expensive. An earlier OEM vac advance dizzy, with a Pertronix, is easy to find and cheaper and might be just as good (a theory I am testing at the moment).
Third choice might be a slightly used OEM small cap dizzy and cap package for cheap that'll probably drop in plug n play and last until you get exactly what you want and serve as a good back up...
 
That would be a desirable end result. I understand they can be hard to find and expensive. An earlier OEM vac advance dizzy, with a Pertronix, is easy to find and cheaper and might be just as good (a theory I am testing at the moment).
Third choice might be a slightly used OEM small cap dizzy and cap package for cheap that'll probably drop in plug n play and last until you get exactly what you want and serve as a good back up...
Interesting. I'll send you a DM.
 

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