My '85 MGM, "Maisa"

[Arquemann]

I love learning these weird little things that can be different, though I'd rather not do it the hard way. Also I should've looked at the distributors maybe 24h earlier so I wouldn't have to wait till monday.

If I can't get the correct cap from the store, I think I'll return the distributor as an incorrect part. Though my dad certainly believes that the round rotor is just as common. Is this other type of rotor only for 84-85? All 302/351 cars/trucks?
RA does show the bigger rotor, but the distributor listing all show the stub type rotor mounting.

On a side note: Today was the first time I started the car cold with the spout unplugged (aka non-fcked timing), it started way nicer and ran smooth straight away. It didn't need the choke at all. The timing issue made the cold idle so uneven that it ran way slower rpm and made it stall like a cold carbed engine.

[gadget73]

part listing shows trucks from 84-88 and cars from 84-85 only. Guessing thats 302 only. The 351 cars ran Duraspark, which is a different distributor. Rotor on that is almost the same as the rotor in your car.


If you're really feeling impatient and adventurous you could swap the shaft from the distributor over, but that involves driving the pin out of the gear and pressing the gear off. At that point you may as well just buy a pickup coil instead and rebuild the existing distributor.

[Arquemann]

The car runs properly now! Not perfect or very close to it either, but it's nicely driveable now.
But damn did it fight me to the last bit.

Got the correct rotor from the store. "-That looks like a GM rotor, are you sure that's what you need? Is it from a boat?" And then the old guy comes to the counter and says oh that's that thing. Goes and gets the part and off I go.

I went through every possible combination of sockets, wrenches and other things to get at the distributor hold down. Eventually got it with a regular open-end wrench coming at it from below the alternator.
Couldn't get the old TFI off the old dist, I needed the bolts for the new TFI and dist. The holes in the module are so deep and narrow I couldn't get anything socket headed to the bolts. Ended up digging through "the bolt bin" for a couple phillips head bolts and used them.

For some reason I couldn't get the new distributor to match up the timing in the same position as the old one. Old one was almost all the way clockwise, I ended up rotating the plug wires and now the TFI points at the front corner and actually has adjustability both ways.
Even managed to get the plug wires wrong somehow the first time, a couple puffs and pops and I get to redo them all.
Got the timing set to the mark from last fall, seems happy. The engine tone changed quite a bit though when the spout was reconnected.

Fires up nice(r), runs well enough cold to not care about the choke. Cold idle good, hot idle is a bit burbly and shakes a tiny bit and has a very slight intermittent rolling idle. CFI anyone?
But it doesn't jerk anymore, it's actually driveable now. I'm super sceptical now so everything felt uneven on the test drive... Yeah the front discs are warped or so and the shocks were probably done 10 yrs ago.

Next up:
Annual inspection on 11th of May. Then we'll see if the emissions values are fucked, and if they are I'm fucked too.
But the things I'll be fixing next are the driver door alignment and the cruise control. Maybe redoing the vacuum lines too.


I am incredibly exhausted, it's been a summer and fall of cursing, a winter of regret and about 2300€.
Thanks to everyone that has helped me with this car.
Now it's just the fiddly bits / everything else left.

[gadget73]

"oh, that one" is the response I've gotten any time one of that style shows up. I really do not know what the deal was with that rotor. And yes it does look like GM HEI stuff.

sounds like the old one was in a tooth off. It should be roughly mid-way through its possible range of motion. If its hard against the water pump or the intake, its off.

[Arquemann]

Went for a bit of a cruise, oh my it drives so nice, it's like I finally got the car I bought last summer.

What I noticed today, I think my AC gas has fizzed away during the winter. Unless these things have a temp switch for it to come on. I'll have to check later if the compressor doesn't come on anymore.
Maybe I should first leak test the system, after that maybe do a R134a conversion. Mostly due to the R12 substitute costing a metric shitton. Last summers refill cost me 190€, it did work for the whole summer, so cant be a big leak.

Also the passenger front door lock decided it didn't want to work, some fiddling with the door handles and central locking got it freed up.
I think need new shocks too.

[sly]

Door lock actuators are notorious for freezing up during the winter. Water condenses in them if not drips directly into them via the rod and rusts them from the inside out.

[gadget73]

bad dew wipes make this even worse. The rain drips into them. There is supposed to be a rubber or plastic drip shield above the door latch to keep water out of the latch and lock motor but it usually falls apart. You can probably see where there are small screws going through the door just above the phillips screws holding the latch in place.

[Arquemann]

I have a bit of a dilemma.

Regular auto shops have dyes to put in the AC system, but it goes in with oil, the wrong type of oil. Shops can't do crap about a R12 systems. Also my AC lasted full blast all of last summer, so the leak is minuscule.
The refrigerator / cooler shop I got the AC refilled at last year doesn't have dyes at all. They do still have terribly expensive Isceon 49.

what I've done to convert R12 systems to R134a, assuming the compressor wasn't actually bad
pull the compressor and dump the oil from it
remove the drier
flush the evaporator and condensor
inspect or replace the orifice tube. If its got trash in it, change it
replace all of the O-rings, lube them lightly with fresh ester oil.
install the conversion fittings. Use the kind that replace the schrader valve, not the kind with the long pushrod that uses the old R12 valve. Those tend to stick and cause leaks.
use ester oil to replace all the now-missing oil. If you have an oil injector, you can do this after you pull vacuum otherwise I've just split it among the components. Don't dump a bunch into the suction side of the compressor, it will not appreciate a giant slug of oil. Oil with dye, or dye seperately isn't a bad idea for future leak-hunting with a UV flashlight.
install a new drier
pull vacuum with a refrigeration AC pump, and let it go for a good while. Bare minimum 30 minutes but longer is better.
charge with about 75% R134a, tweak as needed so things work right.
Optional, back out the adjuster screw on the low pressure switch by about 1/4 turn. It should cut out about 20 psi, R12 is somewhere in the 25-30 psi range. Screw is under where the electrical plug is.

The ester oil won't react badly with any trace mineral oil that is still in the system. PAG oil doesn't play so nice. Leave the drier capped as long as possible. You want it to be un-sealed for the least amount of time possible.

people make AC out to be way more difficult than it truly is. It usually leaks at connection points, it can't have moisture in it, and it can't be contaminated with dirt.

thats specific for R134a, other refrigerants might want different oil. The hydrocarbon ones want mineral oil. The amount of charge vs R12 will also change somewhat.

of course replace any parts that are bad in the process. If the compressor blew up, you're likely to have a load of trash in the condenser and probably the orifice tube. Replace or flush as needed.

Should I rebuild my compressor? The new ones are about 200€ The bearings are going bad and it's really filthy all over, it's where I suspect the leak most likely is.
The compressors are compatible with the R134a and R12 as long as the oil is correct for the refrigerant?

I also need the O-rings, valves and should probably get an orifice tube for good measure. Anything else I should think about?
Evacuating and flushing the system I'll get done at a shop, I do not have any of the equipment for these jobs. Atleast I should be able to pressure test some components.
Probably get the system evacuated, flushed and the rebuild it myself, I can get the new oil in myself and then have it recharged professionally.

[Arquemann]

And yeah my dew wipes are rock hard and split in a few spots.
I need to order a bunch of new weatherstripping.

[Arquemann]

Triple post for good measure.

The system I have seems to correspond with this kit:

https://www.rockauto.com/en/moreinfo.php?pk=9826872&cc=1197053&jsn=418

Notably, I hear very faint crackling sounds coming from the top of the compressor (car off completely), could it be the sound of a leak?
I wonder if it'd go away by changing the seals on the top. And if that would fix the leak? I wouldn't mind recharging the system for 180€ if it lasted more than a summer.

Side note:
-Compressor has been replaced, has seemingly non-oem stickers on the back indicating compatibility for R134a and R12 and some small text I could see properly.
-Condenser is in excellent condition at least visually, barely any bent fins, no mushed bugs, birds or squirrels. Probably has been changed at some point too.

[Tiggie]

You can buy UV dye independent of any refrigerant. If your A/C shop told you otherwise, I don’t think I would be doing business with them. https://tracerproducts.com/dyed-refrigerant-oils/

Sounds from the compressor. Is it right after you cut the car off and the compressor has cycled? That is normal as the pressures equalize. But if the compressor hasn’t been on and it’s making noise, spray that thing with window cleaner and see if you see bubbles. Big leak if you can hear it.

If the bearings are bad in the compressor, I would replace that and convert to whatever refrigerant is readily available in your area. Certainly replace the accumulator. Flush, and if the compressor is putting metal in the system, you need to flush the condenser and evaporator really really well.

[Arquemann]

You can buy UV dye independent of any refrigerant. If your A/C shop told you otherwise, I don’t think I would be doing business with them. https://tracerproducts.com/dyed-refrigerant-oils/

Sounds from the compressor. Is it right after you cut the car off and the compressor has cycled? That is normal as the pressures equalize. But if the compressor hasn’t been on and it’s making noise, spray that thing with window cleaner and see if you see bubbles. Big leak if you can hear it.

If the bearings are bad in the compressor, I would replace that and convert to whatever refrigerant is readily available in your area. Certainly replace the accumulator. Flush, and if the compressor is putting metal in the system, you need to flush the condenser and evaporator really really well.

I haven't driven the car since yesterday and I don't think the compressor has kicked on after the first start from getting the car out of storage.
The crackling sound the compressor makes seems to be coming from between the case halves, I couldn't get the spray cleaner to bubble, but spraying it to the seam made the crackling noise instantly quieter. After spraying it was juuust barely hearable.


I found exactly one store that sells the UV dyes to individuals, others only to businesses and such.
And that one had all sorts of mixed info, the 2 items that claim compatibility with POE (ester) oil, say it's for systems using R134a. And one PAG oil compatible dye claimed to be compatible with R12...
Anyways, the POE compatible dye was 45€ for 12 syringes of 12,5 milliliters or 59€ for a bottle of 250 milliliters. I think the syringes can be emptied into the AC system through the valves, but the bottled stuff I can't do anything with.

R134a is compatible with PAG and POE. R12 (and the available substite) uses mineral oil or POE.
A good read:

https://www.hagerty.com/media/maintenance-and-tech/air-conditioning-dos-and-donts-refrigerants-and-the-law/

[gadget73]

What do you mean by compressor bearing exactly? If its the pulley on front, that can be replaced without opening the AC system at all. That will only make noise when the AC is not running. If its a rattling sort of noise only when the compressor is engaged, that might just be the noise they make. The compressors do make some amount of noise. I've never actually run into bad internal bearings on an AC compressor unless the compressor had totally fragged. The bearings fail from lack of oil, and that ruins the pumpy bits of the compressor too.

If its the clutch bearing, you can replace the whole clutch or take it apart and change the bearing. Not real difficult, but sometimes its a bit annoying. The front plate has to come off. There is a nut in the center of the hub. The tricky part is that you need to hold the front plate somehow. There is a goofy triangle tool that goes into the U shaped notches for this. If you've got a couple bolts and a piece of metal you can make your own. The nut isn't extremely tight. Once thats off, the plate may slide out, it may not. Sometimes it needs a puller, which is just a short fat bolt and a small one inside. Those are available and not real expensive. Once the plate is off, you may find shims on the compressor shaft. Grab them if present. If there were no shims on the compressor shaft, see if they are up inside the front plate. They can be inside the plate, just don't lose them or the gap will be wrong and the clutch will drag.

Under the front plate is a snap ring. Remove that. The pulley with bearing will slide off. The bearing just presses out of the pulley. I don't think there is a snap ring but just have a look in case I'm forgetting it. I don't remember if the bearing pushes against a shoulder so have a look on both sides to see if it matters which way it has to go.

Put it back together how you took it off.

If the system isn't open you need a dye injector to get it in there.

https://www.amazon.com/Injector-Refrigerant-Coupler-R-134a-Refillable/dp/B07G37CVCY/ref=psdc_15727741_t1_B001T9AREK

for example.

All the dye I'm finding says it works on both R134a and R12.

[Arquemann]

It's seems that it is the clutch bearing that's going out. The noise is only when the kompressor kicked on, though it hasn't done it anymore since the pressure is low it won't come on.
The noise is quite loud, easily heard inside over the car running.

https://youtu.be/j7yflp1WFrU?t=107

This video has a very similar grinding noise.

I don't know if there's any point replacing the clutch/bearing if the casing is leaking out the refrigerant. RA didn't seem to have rebuild kits for the kompressors.
The biggest issue with doing this AC stuff myself is the cost, I don't have any equipment for this stuff and said equipment is insanely expensive locally, even the amazon listing linked can't be shipped to Finland due to the coronacrap.
I have a single car and I don't intend on doing much ac stuff anyways.

Maybe I should get the system evacuated and flushed, order and install new o-rings,valves, kompressor, and drier. I can put the stuff together and oil the seals and so on myself. Then I'd get the thing dried, oiled (with dye) and recharged.
Then I'd have a maybe-leak-free R134a system that regular shops will touch. And if it leaks, it can be diagnosed easily and most of all: recharging won't cost 180€ or more.

[gadget73]

Pull the belts and give things a spin, you'll figure out where the noise is. Bad clutch bearings will be noisy when you spin the pulley. Same with the idler. If its quiet until the compressor engages ts something inside the compressor. Just watch if its an internal compressor noise that it hasn't blown parts of itself through the AC system. Normally it will end up in the condenser in front and the orifice tube. If flushing produces chunks, make sure its flushed until chunks stop coming out. I did the one on the Continental with mineral spirits followed by air to push it out until it ran clean, then acetone as a final flush. The acetone evaporates quicker than mineral spirits. Lots of air to make sure it was totally dry, and let it sit overnight just to be sure.

If the case is leaky then you need a replacement. There is an O-ring between the case sections.

Rebuilding it and going with a refrigerant you can get worked on makes sense. The only reason I'm trying to keep my one R12 system R12 is because I have a few cans of the stuff. If not for that it would get converted. Its also currently completely empty and I have the vacuum pump and gauges that I got for less than the price of having one AC system recharged.