@ Anyone come across a 2F Engine distributor bore hole being too small? (1 Viewer)

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Joined
Mar 24, 2025
Threads
1
Messages
7
Location
Aurora, Oregon
I'm a noob here, so thank you in advance for any assistance with this question. I've been reading the forums here for a number of years and have yet to find a question I have that hasn't been answered or in the very least discussed here until now. I've searched the depths of the internet, spoken with an engine rebuilder, and discussed this with local FJ40 rebuild shops, but they haven't seen or heard anyone having my issue.

In 2020 I began a rebuild of my 1976 FJ40. I brought the engine to a reputable engine rebuilder in the area who does 2F engines. He was back-logged over a year, but he had one that was ready to go so I traded mine for his. The serial number is 291954 on the "new" engine, which I believe corresponds to a later 1978. Unfortunately covid sidelined my project, so I'm just now diving back into it. Every part from the '76 matches up to the '78 engine with the exception of the distributor. The bore hole is smaller than the distributor bushings above the gears on the shaft. I've tried 3 different distributors at this point. The gears on the distributor fit in the hole, but the bushings above them overlap and sit on the lip. I measured the inside diameter of the bore hole and it's 1.035" and the OD on the distributor bushings are 1.058". I spoke with a local FJ shop and over the phone he checked a bunch of distributors he has from a wide range of years prior and post mine but got the same OD reading of 1.058" (give or take a thousandth). At this point I'm going to have the distributor bushings turned down to fit, but curious if anyone has ran into this issue?

Cheers,
Damon
 
You never provided us with the distributor used, which is paramount.

All of the Toyota points/semi electronic/electronic dizzys from late 60s to 1992 F/2F/3F can be interchanged.

Another reference point is that the Toyota distributors don't have 'bushings' above the gear. It is just the gear and the housing with an o-ring. Go buy a new OEM dizzy for sub-$300usd and never look back. Mix in the 75-77 coil/igniter combo and you'll have extremely reliable spark control.

Distributor shaft should look like this:

1742856194776.png
 
Thank you for the quick and detailed response! I concur, not a bushing but non-rotating shaft maybe? The issue I have is the bore hole is smaller than that shaft so it doesn't fit in the hole once the gear enters and overlaps the top. Attached is a picture the 3 I've tried. From left to right is the one that came off my '76, a new inexpensive one I found online, and a D.U.I distributor that I had on my '76 prior to swapping for the '78 engine. Do you know if the OD on that dizzy distributor shaft measure out to 1.035? The Fj shop I spoke with measured a dozen or so of his and all had a larger diameter (1.058 average) than the bore hole in my block (1.035").

Thanks again.

Cheers,
Damon

20250324_155451.jpg
 
This may sound a little crazy, but is the tip of the distributor lined up with the slot of the oil pump? If they do not align, the distributor will not drop in and seat like it should. The distributor clamp bolts to the block so the distributor does seat against the block.

A picture of the right side of the block would help.

Also, you can measure the shaft of the distributor with a caliper or mic but you need an inside mic to measure the hole in the block. The reason being is that the edges of a caliper will not contact the widest part of the hole so will give you a false reading. Inside mic's will have a rounded contact area or pointed surface to allow contact with the widest part of the opening.
 
Last edited:
This may sound a little crazy, but is the tip of the distributor lined up with the slot of the oil pump? If they do not align, the distributor will not drop in and seat like it should. The distributor clamp bolts to the block so the distributor does seat against the block.

A picture of the right side of the block would help.
That was my initial though too because I've had similar issues on other non-FJ rebuilds and distributor swaps, but not the case here. I've got another 1.5" to go before it comes close to engaging with the oil pump slot. I've attached a few more pictures with the DUI distributor inserted part way. You'll see on one picture where the housing shaft has a slight taper there are some fine shavings where I gave it a few turns with a little pressure and the lip of the engine block digs into the aluminum. It really seems like it's about .020"-.025" too tight by my measurements.

Thanks for the feedback.

Cheers,
Damon

20250324_170912.jpg


20250324_164834.jpg


20250324_170928.jpg
 
According to the last picture, the roll pin for the drive gear sticks out. It's possible it is the cause of your problem. Try seating it flush or slightly below flush with the surface of the drive gear and try inserting it.
 
According to the last picture, the roll pin for the drive gear sticks out. It's possible it is the cause of your problem. Try seating it flush or slightly below flush with the surface of the drive gear and try inserting it.
Good eyes. It's actually flush on the other side (see pics). I'll file that down prior to installation before it goes back in though, it definitely sticks out enough that it could cause an issue. I like the advice to run an OEM dizzy and I'll probably go that route. That being said, it would need to be inserted about 3 inches to hit the inner lip before the oil pump drive. According to my measurements I haven't inserted it enough to get to that point. I have another 1.8" or so to go in before it hits the next obstacle. I think I just have a bit of a unicorn that's a little too snug.

Cheers,
Damon

20250324_174721.jpg


20250324_173707.jpg


20250324_173714.jpg
 
In the countless... well maybe countable, but it is easily in the hundreds of thousands of F series engines that been worked on in the decades since they left the factory... there is no evidence that I am aware of that anyone has ever reported encountering this. It would be an exceptionally unique and unusual problem to have made it out of the factory. How exactly would they have installed a distributor in the first place to get it out the door?

I submit that your primise is incorrect. ;)

None of those distributors you have pictures appear to be OEM units (inexpensive online replacement is not OEM). As wildly unlikely that they are all incorrectly sized, it is still far more unlikely that a 2F made it out of the factory with some sort of kludged up modified distributor stuck in the block to fit a somehow undersized hole.

Go ahead and accurately measure the hole (something more than your eyeball and the ruler from the kid's crafts drawer) and pass that along.

And try installing a Toyota distributor in there too.

Mark...
 
Thanks Mark! Your statement about my premise being incorrect is one that I do frequently encounter and hopefully you're right! I couldn't agree more. lol Attached is pictures of my dial indicator which I've measured, remeasured, and measured again a dozen times by now. One is pic the measurement of the bore hole, and the other is the measurement of the distributor shaft. I've called a few FJ40 shops now, all their measurements are in that 1.058" diameter range and they all tell me the same as you do. I'm close to beating my head against the engine at this point... Before I get to the self harm point though, I'm going to purchase an OEM distributor and give that a try. If that has the same results, I think I'll just roll it onto the trailer and take it to an FJ shop that's about 45 minutes away and confirm the most likely option which is I'm somehow wrongly doing something that is a relatively simple task that I've done many times before on other engines. I won't be too surprised if that's the case... I'll post an update afterwards.

I greatly appreciate the input, and will now be moving on to some self medicating in the form of bourbon for the evening.

Cheers,
Damon

20250324_110438.jpg


20250324_110515.jpg
 
Thanks Mark! Your statement about my premise being incorrect is one that I do frequently encounter and hopefully you're right! I couldn't agree more. lol Attached is pictures of my dial indicator which I've measured, remeasured, and measured again a dozen times by now. One is pic the measurement of the bore hole, and the other is the measurement of the distributor shaft. I've called a few FJ40 shops now, all their measurements are in that 1.058" diameter range and they all tell me the same as you do. I'm close to beating my head against the engine at this point... Before I get to the self harm point though, I'm going to purchase an OEM distributor and give that a try. If that has the same results, I think I'll just roll it onto the trailer and take it to an FJ shop that's about 45 minutes away and confirm the most likely option which is I'm somehow wrongly doing something that is a relatively simple task that I've done many times before on other engines. I won't be too surprised if that's the case... I'll post an update afterwards.

I greatly appreciate the input, and will now be moving on to some self medicating in the form of bourbon for the evening.

Cheers,
Damon


I bet you can find someone with a dist sitting in a box, even if it does not work. it makes for a simple size check before you spend money to buy a new distributor.

Don't beat yourself up too bad. We have all had those days when we fight and fight with a problem and... finally... suddenly the light comes on and we see something that should have been obvious all along. Or at least it feels that way afterwards!

I usually wind up having on of those "sit up in the middle of the night epiphanies" when my subconscious manages to get my attention and tell me where I went wrong. ;)

It is unlikely, but you *may* have found a unicorn problem. It would be an odd one. 🤔

I assume that you have messed with this enough that you have checked for any sign of any burr or damage to the edge of the bore that might be complicating things. It certainly looks fine in that pic that you posted.

Mark...
 
Your hole is what twenty thousands of an inch too small. Take a wide magic tip marker and paint the "bushing" area. Take a 1" wide file to the area, smoothly remove the marker by holding the file flat on the area and taking one pass trying to follow the curve. Advance your starting point to where there is marker showing. Rinse and repeat until the marker is gone. Test the fit - Yes good to go, make sure your oil pump is engauge and timing is correct; No mark it up again, file the maker away, test the fit. Might take up to 4 or 5 passes if you are a light touch.

Mine came to me in 83 with a Delco dizzy from like a 67 Valiant, the PO did put on the Toyota drive gear. I need to make a new internal shaft bushing as soon as the snow is gone in a few weeks. Yea I'll be hot ultrasonic cleaning the Rochester 2 barrel carb too. Early 2000's I had to grease the leather accelerator pump cup.
 
Last edited:
Don't know if this will help, but once after a 2F rebuild , my OEM distributor would not drop all the way in. Turned out that the aftermarket oil pump that came with the ITM rebuild kit was machined wrong. Looks like yours isn't even going in that far, but thought I would mention it just in case
Good luck solving the mystery!
 
This is one of the more interesting threads on Mud right now! I’m no expert but 45+ years of wrenching on the side, have not seen this BUT have had numerous “impossible” situations that were eventually resolved (or sold lol). Check the diameter both directions (this will help answer Mark’s valid inquiry about a bur or ridge.
 
Thanks everyone, the multiple suggestions are greatly appreciated. I went out this morning with a decent nights sleep and a clear head to take a few more measurements as well as check for any lip that I might not have noticed. There was no lip at all, very smooth, but possibly a bit of a taper that I'm not noticing. I'm using this possible taper theory as the perfect excuse to purchase an internal dial caliper. I also checked few times laterally with the block as the previous readings were taken perpendicularly. It is slightly oval by .005", and I got a measurement of 1.040". Next step is to start calling a couple of the local FJ shops this morning and see if they have an OEM distributor I can borrow for a few hours to check the fit. If it doesn't fit, I'm going to take it into one of them to measure and confirm my sanity of lack thereof.

I wish I knew more of the history of this engine. The rebuilder did have this 2F coming from an FJ rebuilder about an hour away so I followed up with them, but they were as puzzled as I was.

Cheers,
Damon
 
Last edited:
Any area of that block casting around that bore that might have taken a hammer hit or other impact? Hard to tell in the pic but it looks like a slight dent at the 7 o clock position in your pic.

I'd probably try a sandpaper cartridge roll that's a snug fit to run through it.
 
(Putting a starter in my 2011, 5.7 Tundra comes to mind!)
PTSD…

I did my 2014’s starter.
Never. Again.

Luckily it lasted 185,xxx miles before the first one went so…
 
This is a wild thread. I pulled my large cap this past weekend to clear space for replacing the side cover gasket, my distributor slides in and out with really no effort at all other than lining up the gear to mesh, and hitting to oil pump slot. Wish I had words of wisdom, I did like the idea of finding an old known TEQ distributor to test fit.
 
I experienced the same issue years ago with my first FJ40, talk about PTSD! I purchased the rig cheap because the shop it was at couldn't find a distributor for it. I figured no big deal and ordered up a Trollhole dizzy. The 2f had a Jasper tag on it so I knew it was a reman but had no other history on it. I went to drop the replacement distributor in and it wouldn't go, simply too big for the hole. I played around with o-rings and such but the body was just too big to fit. Trollhole sent me another distributor and the second one happened to be machined slightly smaller and fit with a LOT of force. I remember it was a fight to get that thing in. Checked oil pressure and set the timing, all seemed well. Drove around a while and hit a bump and my oil pressure went to zero. I was having some issues with the connection at the sender and thought it was no big deal, but I really didn't have oil pressure and seized the motor. I checked and found I didn't tighten up the distributor bolt and it must have popped out just enough causing the loss of oil pressure. I don't remember the details as it was a long time ago, but looking back I am guessing something wasn't right from the start with that engine. I couldn't figure out how it would pop out and disengage (it was after all tight as hell in there) but something happened internally. Either way the motor was toast and I sold the truck because I was young and dumb. IF I were to have a repeat of this situation I would find an oem distributor first and give it a try. If it still doesn't fit, something is wrong and get it back to the engine builder.
 
Have you looked at the head ? did 1F come with smaller hole ? 20 thou with a file is alot of work. Where did the small hole come from ? must have been an application at some point that used a head with a smaller dist hole.
Paging Living in the Past ---- Pardi ? ----- Georg ? ---- Wngrog ? ----

Is it even a Toyota head ? Do the GM heads fit the F's ? Just a shot in the dark--
 

Users who are viewing this thread

Back
Top Bottom