Is this distributor done for?

O

ODTech

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LIke the thread title says.

By the looks of it is it time to replace this distributor?
It's from a W123 200 Mercedes that's running very very rough. There's no consistancy to it though, it will sometimes run better then the next time it's started run worse and always eventualy will sputter then die.

Half of all 4 contact has been burned away. The lower half seems like a porous carbon deposit.
 

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That distributer cap doesn't look too bad, but it is difficult to judge from the photo. If it has a crack it should be replaced without a question. One can try to clean it inside and out with a degreaser, bensene or other cleaner and try again.
The halve of the contacts have not been burned away but machined like that from new.
The item is not overly expensive and depending on age can be replaced as preventative maintenance.
 
Stokstert said:
That distributer cap doesn't look too bad, but it is difficult to judge from the photo. If it has a crack it should be replaced without a question. One can try to clean it inside and out with a degreaser, bensene or other cleaner and try again.
The halve of the contacts have not been burned away but machined like that from new.
The item is not overly expensive and depending on age can be replaced as preventative maintenance.
Click to expand...

I think you may have misunderstood what i was trying to say. I don't mean the half round that houses the metal contact i realise it was machined / moulded that way.
The white section on the half round i think is also supposed to be metal but it seem to have been burned away. It's recessed a little and it look porous.
 
It's been decades since i had a peek inside a distributor and i can't seem to find a picture on the internet of what it's supposed to look like. Google only shows me troubleshooting guides when i try to search for it.
 
ODTech said:
I think you may have misunderstood what i was trying to say. I don't mean the half round that houses the metal contact i realise it was machined / moulded that way.
The white section on the half round i think is also supposed to be metal but it seem to have been burned away. It's recessed a little and it look porous.
Click to expand...

Sorry for misunderstanding you.

The burning on the contacts doesn't look that serious, but as I said before you can replace the cap and rotor as part of preventative maintenance as the parts are not that seriously expensive.
Start the car in the dark (easily achieved during load shedding) and observe the distributor cap and plug leads for stray currents. It may be that you lose some spark that way.
 
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Stokstert said:
Sorry for misunderstanding you.

The burning on the contacts doesn't look that serious, but as I said before you can replace the cap and rotor as part of preventative maintenance as the parts are not that seriously expensive.
Start the car in the dark (easily achieved during load shedding) and observe the distributor cap and plug leads for stray currents. It may be that you lose some spark that way.
Click to expand...

Thanks for the input..

I took the carbon deposit off the rotor with some sandpaper and reinstalled everything. The engine is still sputtering but it's now because of a consistant missfire on cylinder 4.

I didn't see any sparks arcing in the dark but i guess my next step is a new set of plug wires and then new cap and rotor.
 
Try swap one of the other plug leads with #4 and see if the miss moves with the lead or stays on the same cylinder.
 
ODTech said:
It's a new set i put in a while back after the missfire started.
Click to expand...
Swap the leads as suggested and see if the miss stay's on cyl 4 , easy enough on the merc.

Failing that take a compression test, might be something else wrong.

If it is only being naughty when it is hot, check the temperature sender unit, that car might have two, the cold start function can make the engine behave very strangely.
Assuming that's the carburettor motor that carb has a few diaphragms in it that might not be so hot anymore. It is rather fussy about where it gets air from and not so easy to diagnose.

Just a few things to check.:) (and give you some job)
 
Düber said:
Swap the leads as suggested and see if the miss stay's on cyl 4 , easy enough on the merc.

Failing that take a compression test, might be something else wrong.

If it is only being naughty when it is hot, check the temperature sender unit, that car might have two, the cold start function can make the engine behave very strangely.
Assuming that's the carburettor motor that carb has a few diaphragms in it that might not be so hot anymore. It is rather fussy about where it gets air from and not so easy to diagnose.

Just a few things to check.:) (and give you some job)
Click to expand...


Thanks. I'll try that eventualy. I have a strong feeling it's the carb if it isn't ignition related.
The fuel pump broke and the fuel filter is installed before the fuel pump so who knows what pieces of diaphragm and junk the pump sent into the carb.
 
What also doesn't help i guess is the car was standing for a more than a year before i started with it.
 
Should be a carb. I don’t think the 200 had fuel injection until the W124 series.

Edit : Note to self - always refresh before posting. :-)
 
I'm leaning strongly toward ignition problem now. When i took the plug wire off cylinder 4 while the engine was running i didn't hear the clicking of the spark jumping when holding it close to the plug. With the other 3 i could clearly hear the spark jump.

I swopped the plug wires anyway but then the car wouldn't start at all. Swopped plug wires back but it still wouldn't start and when it eventualy did start i think it only ran on 2 cylinders.
 
With a carb it’s highly unlikely that it will affect some of the cylinders and not all of them. My money’s on ignition, and I’m leaning heavily towards plug leads. Before you spend money, it might be worth checking the connections inside the posts on the distributed cap - corrosion there can also weaken the spark.
 
Colin62 said:
With a carb it’s highly unlikely that it will affect some of the cylinders and not all of them. My money’s on ignition, and I’m leaning heavily towards plug leads. Before you spend money, it might be worth checking the connections inside the posts on the distributed cap - corrosion there can also weaken the spark.
Click to expand...

I did attach a pic of the cap in one of my first posts and the verdict was it doesn't look worn out.
 
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