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Discussion Starter #1
Now that I got my dizzy removed, I noticed something immediatelythat was different between the one I just pulled and the used one I justbought.
In the one I pulled, the small internal rotor underneath the coverthat says “DO NOT REMOVE” with the (8) points IS MAKING HARD CONTACT WITH THE “BUMP”ON THE PICKUP UNIT. I noticed this as I spun the drive gear, bump, bump, bump…..

The used one I have spins with no contact.
The manual I have says something like “don’t mess with theair gap, it’s factory-set and should not be adjusted unless the pickup plate isremoved” or something to that effect. Is the “air gap” the gap between therotor points and the “bump” on the pickup? I can see a small air gap there,yes, as the rotor points go by.
Again, the one pulled from the truck makes contact. If thisis NOT normal, how did the truck run? If the truck could theoretically runwhile making contact, could this contribute to or cause my rough-running/stallingshortly after startup?

 

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When I had the rotor arm problem (see related post) I tried to take the arm off the dizzy to check it and it was as tight as a tight thing, wouldn’t budge, almost as if it was welded to the rotor shaft.

In the end I tried to lever the arm off the shaft using a flat screwdriver but just ended up breaking the arm. In the process of tugging the arm and with the dizzy still in the engine the whole shaft moved vertically out of the base by around 1/4 an inch.

My initial thoughts were that it was buggered and to just buy a new one but getting the correct one for the vehicle proved quite difficult and I didn’t want to have to adapt the plug on one of the aftermarket types that can be purchased. In the end I decided to take a look see for myself so I took the unit out of the engine and stripped it down.

Removed the the remnants of the arm and then the plastic cover that protects the star wheel. I also noticed that the wheel points were making slight contact with the pick up lug and found that this was due to the shaft having been pulled out of the base plate and the two sprung weights below it.

The fix is fiddley but doable. Remove the metal base plate and you will see how the two spring weights locate on the underside of it. At this point you may as well strip them off and give everything a good clean and lube in case they have sized.

When the shaft has been pulled to remove the rotor arm it also pulls through this base plate and dislodges it from it’s correct position to allow the weights to function correctly. Unfortunately I have no photos and I’m describing this from memory a few years ago but once it’s stripped, the location of where everything should sit is quite obvious.

The trick is to open up the weights with a small screwdriver against the pressure of the springs and seat the shaft back into the correct position so that it spins freely and the star wheel no longer touches the pick up point. As I said it’s very fiddley and requires patience but if you don’t fix it then the dizzy will not work and could be damaged. In fact, as a unit it’s quite basic once you understand how it is put together.

One clue if you have this problem is that the dizzy cap is very difficult to fit as the centre coil post hits the top of the rotor arm due to the shaft being closer to it than designed. You may also see some slight circular scoring on top of the rotor arm where the centre of the cap that holds the sprung electrode has been rubbing on the top of the arm.

Hope this helps in some way, apologies for not having some photos to explain it better but I was just trying to get the car back on the road at the time.
 

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I fitted a new baseplate the other day and forgot to set the air gap, thing wouldn’t start then I remembered! There are two tall screw posts with a slotted heads that adjust the gap, I set mine at 0.010” and she fired up straight away.

If you are digging around in the dizzy check that the vacuum advance isn’t seized either


Sent from my iPhone using Tapatalk
 

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I believe the manual is assuming that the mechanic at the time is used to setting the gap on point ignitions and based on that experience explicitly reminds the user that there is no need to set the airgap for pointless distributors.

The air gap itself is not all that critical (compared to points), too close and it hits, to far and the signal will be too weak. You can use a feeler gauge. I don't think contact would stop the car from running but will mess with the timing and obviously cause wear and metal particles etc.

The removal of the distributor rotor arm is definitely something you don't want to force. Would even be worth to use a dremel tool and cut some slots to loosen it up. I have overhauled a few distributor over the years and you need to take it out and disassemble to make sure the weights are set right and at that point clean and lube. Stuck weights will really increase your fuel consumption and foul your plugs and valves and it worth making sure it all works as intended.

Needless to say, when you remove the rotor arm lub the shaft a little before putting it back.
 

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Discussion Starter #5
The dizzy I pulled out of the truck had been making contact between the wheel and pickup for a while, you could see wear from continual contact. I have a theory of how this could have happened, and it involves the shopthat did the remote conversion over a year ago…
Anyway, I don’t see how you could lift the shaft at allsince vertical travel is limited by the drive gear at the other end. ?????
What is it about the weights that need to be “set”? I’lltake the base plate off to inspect, but if the weights are free and the springsintact, I’m not sure what else can be done.
Thanks for the tip(s) on setting air gap, I think I’m goingto fit the used dizzy (that doesn’t rub) after I inspect the weights and setthe air gap. Same part #, and the O-ring is in better shape.
Keeping my fingers crossed that this will have a POSITIVEeffect on my rough-running.
 

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The rotor sits on a shaft that rotates on the main shaft to allow advancing by the weights. Normally there is a screw fitted inside the rotor shaft to stop you from sliding those two shafts apart, but I found on some distributors there is a rubber washer fitted instead. If you pull the rotor hard you can dislodge the washer and you end up pulling the rotor shaft up. This can dislodge the springs on the weights and now your entire rpm advance is disabled.

So when you find that your distributor is not all that perfect to start with and you end up levering away at it, it would be worth to just remove it from the block, knock out the the pin at the gear wheel below, remove some screws and just take the whole thing apart, clean it, lube it and reassemble.

The 'setting of the weights' is just a verification that the weight as positioned correctly and the springs are attached as they should be. They can slip off leaving the weights to dangle loose.

Obviously the correct functioning of the distributor can (should) be verified with a timing light after installation.
 

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Discussion Starter #7
I removed the circlip that appears to hold down the star wheel, removed the washer and O-ring, but the star wheel will NOT pull off. Manual doesn't say squat about dis-assembly. Is the SW threaded? Seems like it should be keyed to the shaft so the points maintain relationship with the rotor.
 

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I removed the circlip that appears to hold down the star wheel, removed the washer and O-ring, but the star wheel will NOT pull off. Manual doesn't say squat about dis-assembly. Is the SW threaded? Seems like it should be keyed to the shaft so the points maintain relationship with the rotor.
use some lube and be patient, asides from the guide key it is a snug fit, also below the clip there is a thin washer which houses a normal "O" ring. remove those and it should come up, note the trigger wheel is sided one is a dibbed the other a shallow valley. the valley is where the "O" ring and clip fits.
 

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Discussion Starter #9
So there IS a guide key?!! This is not shown in the manual's exploded diagram.

Thanks, I'll use penetrating oil and patience.
 

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So there IS a guide key?!! This is not shown in the manual's exploded diagram.

Thanks, I'll use penetrating oil and patience.
yes the guide key is cast on to the trigger wheel another tip, is to hold down the top of the distributor shaft as it tends to pull up this is due to deterioration of a very small speed nut, simply find and install a new one.
 

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IMG_1214_Canon PowerShot G9 X Mark II_0_10.2mm_5.0_100s_2048x1536.jpg IMG_1215_Canon PowerShot G9 X Mark II_0_10.2mm_5.0_100s_2048x1536.jpg IMG_1218_Canon PowerShot G9 X Mark II_0_10.2mm_5.0_100s_2048x1536.jpg IMG_1220_Canon PowerShot G9 X Mark II_0_10.2mm_5.0_125s_2048x1536.jpg IMG_1226_Canon PowerShot G9 X Mark II_0_10.2mm_5.0_125s_2048x1536.jpg

There like a castle washer to stop the trigger wheel from spinning on the shaft. Not that one of the castle tooth is larger and fits in the larger slot.
 

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how correct you are, I apologize for the guide comment it has been al least 5 yrs since I last touched the inside of a rover distributor.
 

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how correct you are, I apologize for the guide comment it has been al least 5 yrs since I last touched the inside of a rover distributor.
I only recently took one apart and made some pictures then. There are a bunch of new after market units available, which are surprisingly the same as the Lucas original unit (like identical) which makes swapping parts easy. The only thing I found that is significantly different is the bob weight arrangement with the original Lucase unit being much nicer made and with lighter springs it follows the documented advance curve much better than the more generic after market units.

The trigger wheel does get stuck tight for sure!
 

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Discussion Starter #14
I got the replacement dizzy in and it started! But there's a problem, and the pics you posted may help (thanks!).



It started and was idling slowly, I'm sure I need to adjust the timing with a strobe. But the dizzy cap did not sit down solidly, and sure enough, the cap itself was "wobbling" around as it idled.



I DID succeed in removing the trigger wheel and base plate, but did not remove the weight and spring assembly from the shaft. Everything looked intact, and the springs were attached correctly. I was able to re-install the trigger wheel and snap ring correctly.


When trial-fitting the old rotor to the replacement dizzy, I inadvertently pulled up at 2 different times while removing it, and the shaft DID move up slightly, but I could not tell if it returned to it's original vertical position.


Looking at your photos, and remembering what it looked like when I removed the wheel/base plate, I can't understand how the shaft could dis-lodge vertically and stay that way.


It looks like I can dis-assemble it in the truck to the point I did before (assuming I can get the snap ring off without loosing it) on the bench; if I do this, will it be obvious how the shaft was dis-lodged, and should I be able to get it back in place?


Or, I could remove the trigger wheel and pickup and swap them to my old dizzy and re-install that.
 

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but I found on some distributors there is a rubber washer fitted instead. If you pull the rotor hard you can dislodge the washer and you end up pulling the rotor shaft up. This can dislodge the springs on the weights and now your entire rpm advance is disabled.
I've only worked on the later V8 distributors, which don't have a rubber washer, but a plastic "tophat" piece, that typically falls apart from age and 'aggressive' rotor removal.

Classicpain - see my distributor thread, it seems like i had similar questions and my photos are still attached.

Regards,
 

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Discussion Starter #16
I found what looks like a "tophat" in the bottom of the box I was putting the dizzys in. Can it just fall out? I'll have to check the dizzy I installed, but how does this top hat retain the dizzy shaft? if I remove it, should the shaft be removable?
 

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No, the top hat piece prevents the shaft from moving upwards but does not retain the shaft. The most common way the top hat fails is when rotor sticks the shaft and increasing force is used to pull the rotor up/off. Then the top hat gets crushed, the shaft shifts upward and can dislodge the advance weights.

The WSM has specs to reset the airgap using non-magnetic feeler gauges. I ran up to my local mechanic and asked to borrow his, he couldn't find them since it had been so long since he's dug this deep into an older ignition system. So, after a little test & research, I began cutting feeler gauges from several different plastic bottles until I found the correct thickness! Easy-peasy threw it all back together and ran perfect!

NOTE: this was just one step in my long, drawn-out IAM saga. Eventually I installed the IAM relocation kit and carry two known-good IAM spares in the glovebox.
 

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Discussion Starter #18
No, the top hat piece prevents the shaft from moving upwards but does not retain the shaft. The most common way the top hat fails is when rotor sticks the shaft and increasing force is used to pull the rotor up/off. Then the top hat gets crushed, the shaft shifts upward and can dislodge the advance weights.
Tom:

I read one of your previous posts on this subject with great interest.

This “top hat” part still has me baffled, and I am EXTREMELYfrustrated over the lack of any documentation on-line (that I can find) thatshows pictorially the assembly of the flyweight shaft, and the installation(with tophat) of the shaft on the main dizzy shaft.
So the truck actually ran with the replacement dizzyinstalled and the flyweight shaft dis-lodged vertically (dizzy cap did not restsolidly on the body), and when I removed the rotor carefully, I could easilylift the shaft and reluctor ring up about ¼”, enough to completely dis-engageit from any keys to the main shaft, and spin it freely. Luckily, I marked it’sposition relative to the engine before doing this.
The OLD dizzy, the one where the reluctor ring was makinghard contact with the pickup, is still “intact” as far as flyweight position….theshaft has NOT been dislodged vertically, so my plan now is to swap the “good”pickup and reluctor ring from the dis-lodged dizzy and put them on the old,original dizzy.
BTW, I used a metallic .010 feeler to set the air gap priorto installing the dis-lodged dizzy, and had no starting issues…..is there adanger of damaging the magnet if using metal feelers?
BIG QUESTION: I have (1) loose top hat that I found in thebox with my dizzys….how do I install it onto my “good” dizzy?
 

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Tom:

I read one of your previous posts on this subject with great interest.

This “top hat” part still has me baffled, and I am EXTREMELYfrustrated over the lack of any documentation on-line (that I can find) thatshows pictorially the assembly of the flyweight shaft, and the installation(with tophat) of the shaft on the main dizzy shaft.
So the truck actually ran with the replacement dizzyinstalled and the flyweight shaft dis-lodged vertically (dizzy cap did not restsolidly on the body), and when I removed the rotor carefully, I could easilylift the shaft and reluctor ring up about ¼”, enough to completely dis-engageit from any keys to the main shaft, and spin it freely. Luckily, I marked it’sposition relative to the engine before doing this.
The OLD dizzy, the one where the reluctor ring was makinghard contact with the pickup, is still “intact” as far as flyweight position….theshaft has NOT been dislodged vertically, so my plan now is to swap the “good”pickup and reluctor ring from the dis-lodged dizzy and put them on the old,original dizzy.
BTW, I used a metallic .010 feeler to set the air gap priorto installing the dis-lodged dizzy, and had no starting issues…..is there adanger of damaging the magnet if using metal feelers?
BIG QUESTION: I have (1) loose top hat that I found in thebox with my dizzys….how do I install it onto my “good” dizzy?
I mean, there's little to no documentation on how to even remove the dizzy in the first place.

I did happen to stumble on this video though

https://youtu.be/hSJWx3c8izM
 

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Discussion Starter #20
PROBLEM SOLVED! It was definitely the lack of air gap andtrigger-wheel making hard contact with my pickup that was causing myrunning/missing problems. Symptoms were same as having a bad amplifier module,except it wouldn’t die completely…just stumble down to the point that it wasun-drivable.
I concluded that the shop that fixed my bootleg remote-amplifierinstallation to the factory remote-amplifier replaced my pickup plate and DIDNOT set the air gap, and may have just left the adjustment screws loose.
So although I was at the verge of taking the truck back tothat very same shop and telling them to “fix it” ($500 bill, MINUMUM), insteadI got by with a $65 used dizzy that I used for it’s clean internals, and fixedit myself. YEAH!

 
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