I decided to dive into my ignition system refurb, and the first thing on the list was to replace my vacuum advance, which hasn't worked for pretty much the past 6 years or so.

However, when trying to remove the distributor cap, which should be the easy part, none of them will budge at all. They've been soaking in penetrating fluid for a week or so.

On one of the screws, it simply broke off the top part of the head where your flathead screwdriver would sit, and didn't budge whatsoever. On the second, I tried using a microtorch to heat the bottom part of the screw as best I could, but didn't get anywhere with that either. Also ended up breaking the tips off of 2 or 3 screwdrivers.

On the third one, I tried the microtorch again, combined with a nice metal-body screwdriver with a wrench attached to get some leverage to turn the screw with more force. However, it simply... twisted off about ~20% of the distributor cap, along with an ~0.75" section of the aluminum distributor body beneath it... And the screw still didn't budge.

I clamped the broken piece of the distributor in my vise, heated it with a torch, and had a pair of vise grips locked onto the screw, and tried turning it... And got nothing other than the screw snapping flush with the piece of the distributor body.


At this point I'm out of ideas other than remove the fuel rail and throttle capstan to get more room, break off the rest of the distributor cap to get better access, try getting at them with vise grips, and then drilling and re-tapping the holes when/if that fails.

Any other suggestions at this point? I have never encountered such small screws being this seized before.

 

Bugga.

Someone does not like you.

I have had my fair share of tight screws, but nothing like that.

Being up there, I reckon there will be s/hand distributor bases about. I have one, BUT,, its PreHE and Aust advance curve spec, no good to you.

I suggest setting the engine on TDC #1A Comp stroke, and remove that distributor. It will need to be out of the engine now that it is mangled a tad.

My PDF is attached.

 

You would think that, but seemingly nobody wants to let go of them at any sort of reasonable price, and new/refurb ones are $$$. Obviously I have plenty of time to look around, but it's looking like it might be cheaper to just buy an entire parts car (again). Or I could be lazy and just epoxy back on the broken piece, it doesn't impact the functionality of the part, and it sure would save me a few hundred bucks at minimum.

I'm definitely thinking the easiest path forward would be to break off the rest of the distributor cap to get access to the internal hex screws and/or the rest of the cap screws. Removing the distributor might be tricky if my old parts engine was anything to go off of, the aluminum corrosion had welded the distributor to the block/valley plate(?) to the point where I couldn't remove the distributor even with a 1 meter long pry bar... Ended scrapping the block w/ the distributor still in it when I needed to make space a couple years ago.

 

I hear this shortage more every day, scary.

JB Weld is my go to, many bits and pieces are still working today, thanks to that product. The Original, NOT the Quick Dry rubbish.

Have fun.

 

Way ahead of you on that one haha, I've got a few tubes of the stuff kicking around. I'm heading out to the store over the weekend to pick up some more dremel bits... Seems like the more careful option to remove the rest of the cap compared to brute force.

Removing the distributor is a task I'm not looking forward to, but fingers crossed. If not, hopefully there's enough room w/ the throttle capstan and fuel rail out to get whatever I need done in situ.

 

Yikes! If the dizzy cap screws are that corroded, i would hate to see all the rest of the fasteners on the car. I have never seen a distributor cap screw rusted like that, engine heat usually keeps them uncorroded.

Doug.

 

You don't even know the half of it. I think I had a thread here about the spark plug debacle back in 2018. I'm not even sure why, the car isn't rusty in the slightest, but anything aluminum I've dealt with on here has been a pain.

Every piece of hardware I take off, if even slightly damaged, gets replaced with stainless hardware and a good helping of antiseize. My best guess as to why is environmental humidity here in southern West Virginia.

 

Yes, that level of corrosion on a dizzy screw is unbelievable.

 

Dremeling off the screw heads finally allowed me to remove the cap. Although the pictures don't show it, I was able to remove the flash shield (via breaking the heads off of the screws that hold it) and rotor and get access to the screws that hold the distributor in (thanks for the PDFs Grant)

As expected, the distributor has corrosion welded itself to the block, so whatever refurb it gets will have to be in situ. Couldn't get it to budge upwards even with my small ~1-1.5ft pry bar. Also tried rotating it to try and free it up, and no dice, whatever timing it's at is what it's going to be at. Mechanical advance seized as expected.

The corrosion inside of the cap was much worse than expected... As you can see in the pics below, it looks like someone has had the cap off before (probably 30+ years ago), and then severely overtorqued the cap when reinstalling it. Judging by the cracks and how full of dirt they were, it certainly wasn't any time recent. I'm assuming being open to the air made the corrosion much worse than it should've been. Weirdly the contacts inside of the cap and on the rotor were in pretty good shape.

 

Was there a gasket present? I wonder if left out, would the screws bottom out in the threads, also let moisture in?
I see something that looks like a gasket, mine is a 1/16” thick rubber one.

 

Yes, that's what's left of the original gasket.

I can see daylight through some of the cracks in the cap from whoever installed it before. Amazed it's ran as good as it has for the past 7 years

 

Have you tried drilling it out with a left handed bit?

 

I already got it off w/ a dremel, didn't take as long as I expected.

Going to either try to heat and unscrew the last ~0.5" since i have access now, or maybe weld a nut to them.

The hard part now is going to be getting the mechanical advance freed up... And get the inductor wheel off.... And get the vacuum advance off.

 

FThe BREW mate, ya need The BREW.

50/50 ATF and Diesel fuel,.

Pour it down that centre shaft, and around the top of that star wheel, AFTER the circlip is removed.

LET IT SOAK, a day or 3, depends how big the beer fridge is.

Might, MAYBE, assist with the casing stuck to the centre plate, dunno.

Now this is from MEMORY, and I leave it at that.
IF you get the star wheel off, and then remove the reluctor plate (3 tiny screws, maybe 2 ???), then you can remove the other screws and the "top section" of the dizzy can be removed, with the capsule attached. That leaves the base (same as the PDF snaps), still in the engine. I did this 30 or more years ago, and never again, that dizzy is soooo easy to R & R, its just easier. I know yours is stuck, so ya gotta get outside that box a tad.

 

I agree, I think soaking and time might be the best answer at this point. I filled it up as much as I could this morning with a mix of diesel/atf and whatever penetrating fluid I had left on the shelf.

Gives me some time to shorten up the replacement hoses on my fuel rail and rebuild my AC compressor while I wait

 

I might have a spare distro.
I'll look. If I do it is out of an '88, non-Marelli.

 

Lots of PB Blaster pre-soak to help free everything up.

I have a distributor. PM me if interested. Reasonable $$.

 

I'll let you know if I'm able to get mine freed up (and out of the block!). So far the diesel mixture has allowed me to move the mechanical advance maybe like... a quarter of a degree, whereas it was completely solid before.

 

If you can get it out of the block, put it in some Evaporust. That will take care of the rust, but not any aluminium corrosion.

 

I ended up swapping out the diesel/atf mixture for some white vinegar. After about 72 hours, I was able to get the mechanical advance to move its full travel... Still kind of crunchy, and definitely wouldn't move on its own under regular operation, but at least it's moving now. Replaced the mixture today with the diesel/atf in hopes it should take care of the last of it and provide some lubrication while I move the advance manually over the course of the next week or so.

Still no luck getting the distributor out or the halves to separate, but getting the mech advance moving is massive. Haven't been able to get the star wheel off, but I've also been very careful with it, as I'm not sure what level of force is needed to break it, and I'm dead in the water at that point. Haven't been able to get it to rotate on the shaft either to break the seal.

Hopefully I can get the mechanical advance lubricated into submission, to where it operates normally. At that point, all that's left for me to do in here is the vacuum advance. I got a new set of the short punches that should be able to drive the pin out, just have to figure out how to get the advance mechanism off of the plastic plate without removing the star wheel if it comes to it.