350 SLC 1972 troubleshooting

Hi volker,

Do not worry i am not in a rush. Please enjoy your holidays.

I am just checking my car based on your work and sharing it with everyone reading the forum.

Hi Sylvain,
you are correct - the points unit you got from me is the older version.But this works fine, too - the fibre blocks need a little more maintaince, i.e. they should be regreased every 10.000 km for an almost unlimited life.
The distributor has a greasing-felt, too. It is located on the backside of the camshaft.

You could interchange the whole points unit from ane chassis to the other when having outsoldered the wires. Below rhere are two screws holting the very contact unit.
But I wouldn't do this.
The unit you got is in really good condition - and you can leave the other unit as a spare.
We noticed more then onte time workshops or users didn't install the points unit <still being sold by Mercedes / Bosch at a very high price> correctly and had trouble afterwards.

Regards
Norbert

nordfisch wrote: Hi Sylvain,
the behavior is o.k.
Pressure is allowed to sink to 1,8 Bar - and has to hold then for a minute or so.

Please check your measuring device. We found out the manometers are misadjusted quite often.
Cross-check it with a reliable unit - maybe a tyre-manometer professionally used at a gas station.

Regards
Norbert

I did 7 tests with 4 different type pressure Gages.
I have noticed difference between - 0.1 bar, - 0.18 bars and - 0.3 bars.
All differences are constant with the tested gage.

I can confirm that my gage tool is probably a little lower than the real pressure, around -0.1 bar.

My previous results are mainly corrects.

Today i conducted a spray test of the injectors.

It take a little bit of time because you need to lift up the fuel rail with the injectors, remove the 8 bolts locking the injectors, the 2 bolts for the cold start injector and the 2 bolts holding the fuel regulator.
There was some cooper grease around the injectors, probably to ensure there is no leak at the seals. the seals were in good shape.



Here is my test bench with 9 water bootles.



The test is in the following video.


All injectors seems to be spraying correctly the fuel.
There is no drop of fuel nor leaking.

At the end the fuel quantity is more or less the same in all bootle.

I have tested with both of my ECU and the results are the same.

I asume my spray test shows that my injectors are OK.

I didn't get any fuel from the cold start injector. But i did make the engine run for 30 seconds before the test and it is a warm day today in Paris.

Hi Sylvain,

spray test is very rudimentary. Especially if you use large bottles as you did. Meaning you can hardly measure and compare volumes like that. You should have more equal shaped glasses. When I first bought some graduated measuring cylinders and tested with those I was surprised to notice a slightly more than 10% difference in injector volumes. After cleaning them they came down to 2-3%. With your bottles you would hardly notice 20% difference. Even with small jam glasses it is already difficult.

So all I want to say: Do not overvalue the spray test on volumes. It is good for checking leaks and spray qualitiy.

Hi volker

Thank you for your advice.
I will weight the fuel using a kitchen scale. It should be precise enough to compare the fuel quantity.

Also previously you told me "You also did not check potting". What is that ?

Regards
Sylvain