Lean Burn / SCC trouble...

[Deleted member 1959]

Hi Bud
I will try to have the carb adjusted before I order a rebuilt one. I trust the rebuilt ones will have brass floats in them instead of plastic ?

 

[BudW]

Plastic floats are cheaper to make than brass is, so chances are very high it will come with plastic.

Actually, plastic floats in Holley carburetors were a problem back in the ‘80’s – which is why the aftermarket came out with brass replacements (this is well before Ethanol came out).

I wish I had the $ to fly down and get it fixed for you (then you could show me the local sites, and such there) – but that’s not going to happen.

That carburetor is not hard to rebuild – if you had done one before. First timers – is bit intimating, unless you have someone there to give tips while you do it.
BudW

 

[Deleted member 1959]

Hi Bud
The rebuild option is probably the way to go. I can find tips and tricks on youtube, and then I have you also
It costs an arm and a leg to have things shipped over here, so a rebuild kit is much cheaper to order and ship. I also have to pay the Core charge if I don´t ship the old carb over there, and that will cost much more than the charge.
I am thinking I might as well get on ordering the parts.

Any other things you can think of that I should order from Rockauto ?

Yes a trip to Denmark would be nice this time of year - today we have 27 deg C. and sunny weather. Perfect for cruising. Unfortunately I had to work...

 

[BudW]

It is already 36’ C (97’ F), today, but will be about 27 C tomorrow. In a couple of weeks we will be about 43’ C for a couple of months.

I have to work this Saturday, as well – so I know.


After a quick Google search, I did not find any brass floats available out there, that would fit a Holley 2280.

- The Standard 1420B carburetor kit is a good kit, to use.
- Always replace the fuel filter when cleaning a carburetor (unless recently done), with a quality filter.
- Test your choke pull off. If it fails, replace it. If existing one holds vacuum, then reuse old one (more about this later). If needed: either Standard CPA314 or Airtex/Wells 1C1165
- If Ethanol is being used – always replace the plastic float. Standard FL26. One can always test a float (once removed) by placing the bare float in water. It should stay well above the water line. If it sinks or sits low in water line, then it’s a goner. For cost of a float and availability of them there, I would definitely get one.
- Not directly related to carburetor – but I highly recommend getting the Choke Thermostat (either Standard CV189 or Airtex/Wells 2C1117). After 20+ years, the bimetallic spring on those get rusty, preventing them from working correctly.


To perform repairs, you will need plenty of work space. A desk or table is fine. I recommend placing scrap cardboard down on top of your work space. Cardboard protects your work table/desk as well as your carburetor.

A Factory Service Manual (FSM) in book form or digital format. This one would be good (or one like it) http://www.ebay.com/itm/Mopar-NOS-Service-Manuals-79-Chrys-Plymouth-Dodge-/8040458355?hash=item1df3fa873:m:mkqMazGQbe8hJyBu0CJNCcQ&vxp=mtr

Carburetor cleaner. Spray cans as well as to dip parts in. A 2-bbl sometimes can fit into a 1 gallon (3L) can of cleaner. 4-bbls will only fit into a 5 gallon can (18L) – but overkill in this case. Most cans come with a metal dip tray inside (which is handy).

Two pair of heavy rubber gloves (or similar material). Carburetor cleaner will eat through just about any material, if exposed to it long enough.

A large container full of hot/warm water to rinse after dipping parts, into. This container is not to be used for anything important afterward (like for food storage, etc.). A 5 gallon bucket works great.

A good set of drill bits. Not for drilling – but for measuring. I would get out the factory Service Manual (FSM) and look at what measurements one needs to make sure you have that “measuring device” available. An example is drill bit of 3.5mm in diameter for measurement “A”, for example.

Clothes that you don’t mind getting dirty/smelly. Carburetor cleaner has an odor that is hard to get rid of.

Carburetor cleaner will soak into the skin, and will make skin tingle – so less exposure to it, is better – but it won’t hurt most people. I have no problem not using gloves – but wife won’t let me back into the house for a few days afterwards – so you can choose.

Taking your time and make sure that all of the adjustments/measurements are spot on – is key to success. A rushed job or skipping steps will most likely leave you where you were to begin with.
BudW

 

[Deleted member 1959]

Hi Bud
Thanks a lot I will order all the parts now and let you know how things are progressing.
Wow 43 deg C. for months... I hope it´s dry heat and not like the kind they have in Florida

 

[BudW]

Arizona is where we have the dry heat
In Oklahoma, we get low humidity in winter and high humidity in the summer – but I wish it was the other way around. In late July or August, you go outside and the hot humid air hits you and zaps any energy out of a person. If you wear glasses (like I do), sometimes your glasses will fog over at same time. The “feels like” temperature is generally around the 48-50' C range. You hop into a closed car parked in sun all day – and there it gets really hot.

Note, my blue '77 wagon came with no A/C, so I know to carry a towel to place down, before I sit on those vinyl seats.


Back to an earlier statement. You will want to test your choke pull-off before ordering one.

These pictures are from a Thermoquad – so appearance will be different, but procedures will be the same.
Perform test with engine off.

Choke pull-off will be on passenger side of carburetor.

Find hose and pull it off (temporary).

With one finger, push the rod and linkage towards and into the vacuum chamber.

With another finger, plug the vacuum hose nipple (as shown).

Let go of the linkage. It will move slightly but should stay in a down (pushed in) position for some time. Slight leakage is not a problem (but does, indicate a pin hole in diaphragm).

This one is bad, and linkage fully extended in about 4 seconds (with vacuum port plugged).
Note: finger is still plugging the port, but camera didn't take a good enough picture to show it.

If you have access to a hand held vacuum pump – you can use it to test it as well, but the finger test is a lot faster.
BudW

 

[Deleted member 1959]

Hi Bud.
Thanks for the detailed testing instruction. I already ordered a new choke pull off since it was fairly cheap. I will test the old one anyway when get the parts sometime next week.
I guess there must be something good about living in Oklahoma despite the weather ?

 

[Deleted member 1959]

Hi Bud
Jut got back from a trip to Finland. Lots of lakes and forests and friggin´ cold - 6-15 deg. C.
The parts will be shipped on Thursday so it will be 1½ weeks before they get here. In the mean time I will check the spark plugs. They were replaced two years ago when the car came to Denmark, I just want to see if they look ok.

Once I saw a mechanic pour a whole club soda into the carb of my dads 1977 Volvo 242 to clean out carbon deposits from valves and pistons. The engine was running while he did it. It sputtered quite a lot but kept running. Have you ever heard of this treatment ? I was thinking if it could in any way hurt the engine or if it´s a good trick..

Do you know if Chrysler has a historical records centre where I can get a certificate with all the factory data on the car ?

 

[Dr Lebaron]

Do you know if Chrysler has a historical records centre where I can get a certificate with all the factory data on the car ?

Sorry, not going to happen.
They closed shop and any 77-79 M info really sucked when it was open.

I can decode the data plate and Vin, maybe get a total made, but that really only works with T tops, sunroofs or 360's.
I also know where to get parts for these things, because I am a Dr. of Lebarons.

 

[Dr Lebaron]

Never heard of the club soda and would never try it.

 

[kkritsilas]

I have heard, from some very old timers, that water (in small amounts) could be used for this, mostly to clean off combustion chambers (including valve faces) and pistons if they had carbon deposits. The idea was that the water would turn to steam from the heat of combustion, and sort of scour off the carbon, which would then go out the tailpipe. I don't know how valid it was, and even in our cars, it sounds like it would clog up the catalytic converters for those still using them.

I have never tried it, and don't intend to.

 

[Dr Lebaron]

I can tell you some parts you a never getting NOS,
the rubber seals around the windows, depends on which wheel well moulding.
T top and sunroof seals if you had one.

A 77-79 M pro parts tip.
Gas doors, only a 77-79 thing.
Bust yours and ouch.
But they still can be had and generally don't rust.

Also a 77 and 79 part might be the same, but will have 2 different numbers.
May strike out with one number and find it under the other.

 

[Deleted member 1959]

I could use some new rubber seals around the upper edge of the door windows. They are a bit cracked.
If you know where I can get them, NOS or new, please let me know.
About the historical records: I do have the Production Broadcast. It is still in the trunk glued to the floor in a very fragile state. I can see from the VIN that it was made in Fenton, Missouri in Jan. 1979, but I don´t really know how to decode the whole broadcast sheet.

 

[Deleted member 1959]

Is there any way of testing the vacuum transducer connected to the SCC ?
My concern is that when you pull the vacuum hose off when the engine is running, nothing happens to the idle speed.
I checked the diaphragm yesterday and it seems to hold vacuum fine. The two wires coming from it looks ok too. I guess it translates the movement of the diaphragm into resistance (ohms) ?

 

[BudW]

Vacuum Transducer?

The one on the Lean Burn/SCC computer or the one on passenger side outside of carburetor?

The Throttle Position Transducer (on todays cars, its called a TPS) is the one on passenger side of carburetor and it measures resistance as well as rate of change of resistance.

The Vacuum Transducer measures the intake manifold vacuum.
Two different checks you can make. One, with engine running, remove vacuum hose at computer, and check to see if you have vacuum present by placing a fingertip at the vacuum hose or put on a vacuum gauge on end of hose.
Sometimes, the vacuum hose going to computer gets disconnected at source – which happens sometimes.

The next test is to either put a vacuum pump on the vacuum transducer (at computer) and apply vacuum and monitor timing difference. Or take a piece of vacuum hose and suck on it (which is doing the same thing as a vacuum pump).

The engine speed should not change much if any at all.
However, the engine timing should change according to vacuum level present.

Engine speed is more effected by air/fuel ratio and by idle speed, than anything else.
BudW

 

[BudW]

Great, you have a broadcast sheet!

They quit leaving those in cars in the mid to late ‘70’s – but still used the sheets (they discarded them instead of just leaving them in the cars).

It would be nice to get this sheet scanned at a high pixel rate, so one could read it better, when blown up.

Most of it makes sense to me – other than I just can’t read yours.

I blew up a portion of the sheet that I could read:
Line 4
Exhaust LT (not legible). Rt 816
Cat 878
Muffler LT 000, Rt 956
T/Pipe Lt 000, Rt 000

Line 5
P/B hose (power brake) 71
Mas Cyl 74
(Can’t read) 81
(Can’t read) in 37, out 31
Clutch/Brake 68 00
Car Height (can’t read first two positions) 8
(Can’t read) 15 42

Line 6 (can’t read)

Sales Codes
A 03 91 (which translates to Sales Code A03 and A91, and so forth
These sales codes may be on fender trim tag – but not necessarily.


The digits on sheet, just below the description, are the last two (or three) digits of the part number.

Now with that said, many items come from venders pre-assembled, for example the muffler. Tailpipe and resonator (if equipped) comes as one huge assembly. The brake booster and master cylinder also come as one assembly. The brake (and clutch) petals with pads come as one assembly – so the part numbers on those DO NOT directly correlate to the parts manual.

Some things do directly correlate with the parts manual – like catalytic converter for example.

If you notice the Catalytic converter from the part manual page, mentions sales code N94 (US 49 state Lean Burn) – which is also mentioned in the Sales Code “N” section (as 94}.

It is a puzzle - but hey - at least you have one.
I would say most of us, do not have one (factory's deemed it to be a fire hazard, or something to that effect).
BudW

 

[Deleted member 1959]

Vacuum Transducer?

The one on the Lean Burn/SCC computer or the one on passenger side outside of carburetor?

The Throttle Position Transducer (on todays cars, its called a TPS) is the one on passenger side of carburetor and it measures resistance as well as rate of change of resistance.

The Vacuum Transducer measures the intake manifold vacuum.
Two different checks you can make. One, with engine running, remove vacuum hose at computer, and check to see if you have vacuum present by placing a fingertip at the vacuum hose or put on a vacuum gauge on end of hose.
Sometimes, the vacuum hose going to computer gets disconnected at source – which happens sometimes.

The next test is to either put a vacuum pump on the vacuum transducer (at computer) and apply vacuum and monitor timing difference. Or take a piece of vacuum hose and suck on it (which is doing the same thing as a vacuum pump).

The engine speed should not change much if any at all.
However, the engine timing should change according to vacuum level present.

Engine speed is more effected by air/fuel ratio and by idle speed, than anything else.
BudW

Hi Bud
I am talking about the one connected to the SCC computer. A colleague pointed out that the revs should change when the vacuum hose is disconnected, which it didn´t. This was the hose that was broken when I first got the car, so I thought the stall problem came from this.
There is vaccum present when you pull the tube off with the engine running, so that´s ok. So I will try to monito the timing next - thanks !

 

[Deleted member 1959]

That is impressive how much you can tell from this sheet ! I would like to get it out of the car, but I am afraid it will break.
Is there any way of telling from the sheet to which dealer the car was meant to be shipped from the factory ? It would be fun to have as much history about it as possible. It was auctioned by a classic car dealer in Boise, Idaho, and the description says it was previously driven in Washington/Idaho by two owners.

 

[BudW]

Is there any way of telling from the sheet to which dealer the car was meant to be shipped from the factory ?

Maybe – but I doubt it.

The Build Sheet is mainly the “shopping list” for the assembly of the car, and not really meant for anything else.

I have seen and touched hundreds of Build Sheets – but this is the first one I recall seeing for a ’79.
I agree, they do get brittle – and that fact is only going to get worse as it ages, not better.
My recommendation is to get a plastic sleeve for the page to place it in. Maybe even sandwich it between a pair of clear plastic plates? (so it can’t flex).

Just make sure the storage location is not where the sun doesn’t normally see it (sun will fade it completely out, over time).

Maybe F Body Deconstructor Jim has been keeping Build Sheets from (or for?) his collection. Now, I’m curious as to how many he finds?

Most of the ones I seen, was when I worked for Chrysler years back – and they just got in the way. I have kept a few of them over the years and gave to next owner of the car – but never took time to go looking for one.

My ’77 wagon has a 3” (7cm) triangle of a sheet taped to the black instrument cluster frame – that appears the rest was ripped off, during assembly. There might be others in the car – but not taken anything apart to find out (and don’t plan to for a long time) – but I doubt it.

The cars made from around ‘73’ish and down, you could find a bunch of the sheets in a car, sometimes, in various locations.
I “think” the assembly workers were instructed to toss sheets one done – but IDK. Might have to find a Chrysler assembly plant worker and find out.
BudW

 

[Deleted member 1959]

Hi Bud
My sheet is "glued" to the bottom of the trunk under the carpet. This has kept it out of the sunlight and saved the print I suppose. I will try to get it out of the trunk tomorrow so I can save it and have it laminated.
I didn´t know there could be more than one lying around in the car.
What did you do when you worked for Chrysler ?