350 SLC 1972 troubleshooting

I have weighted the fuel quantity following my spray test.

Injector 1 : 6 g of fuel
Injector 2 : 6 g of fuel
Injector 3 : 6 g of fuel
Injector 4 : 5 g of fuel
Injector 5 : 6 g of fuel
Injector 6 : 6 g of fuel
Injector 7 : 6 g of fuel
Injector 8 : 6 g of fuel




For me it is ok.

i just need to open the kitchen window before my wife come home and get rid of the fuel smell.

Hi Sylvain,

having to empty the kitchen before house dragon returns home reminds me of something

I have done such tests and ultrasonic cleaning with graduated measuring cylinders on the balcony and got a lot of complaints due to the smell from balcony to living room. I should ask you the tolerance of your kitchen scale and I guess it is more than 1 g. I can really tell you that I was myself surprised when I did such cleaning and measuring with graduated glasses and found a more than 10% deviation on seemingly well working injectors. And their variation of far more than 15% really went down to less than 4%. Since then I am not so fond of my early spray test method versus marmalade glasses any more. It works to see leaking or badly spraying injectors. But the proof comes with varying speed and graduated glasses. If you have reason to believe they are not working properly, find someone with an ASNU service.

After several weeks, i am back.

Following my last test, the only remaining part that needed to be tested was the ECU. ANd finally I got it repaired.

The french post office almost lost the package but i magage to get it early july.

My ECU was missing some isolation plate and some bolt and washers.
With luck i had another (non working ECU) and took the parts from it.



I plug back the ECU to the car and ... it started the M116 right away.
The engine was working correctly even if i was on a basic ignition timing adjustment.

Cold start was OK
Cold idle was OK (around 1000 rpm)
Hot start was OK
Hot idle was OK (around 750 rpm)

After few kilometers around the block mainly to get some fuel, i descided to go to Le Mans Classic with the car.




A 3 days roadtrip (with some other w107) with outside temperature around 35°c.



Incredible week end, i even had the luck to get a full access badge to be very close of any part of the race track.


The car worked well in the hard conditions (hot days, lot of traffic james around le mans ...).
The average speed was 160 km/h on the highway, evenif the engine was a bit lazy around 5000 rpm.



I came back to Paris after 500 km of Djet testing and it was OK.
Great news after all the tests conducted on the car.

Two days afer my return to Paris, i took the SLC for a quick drive, only to have a breakdown 4 km away.

It was not caused by the Djet but only by the clutch system.
The clutch pedal was not coming up.


It came back on a recovery truck.


I ordered right away a clutch master cylinder, a slave cylinder and the small hydraulique pipe between them.

Then the fun started ....

It is a real pain to change the master cylinder due to the limited acces upside down.
It is killing your back too. I thought it will be the more complicated task and i was really wrong.

Removing the 40 years old pipe on the clutch cylinder was way more challenging.
I had to buy a pipe wrench (normal) and modify it (cut it in half) due to the very very very limited acces at the right of the gearbox.

Finally it was the hydraulic flush time. It took me even more time than the two previous task.

I tried a basic power (using air pressureas i do for the brakes) bleed from the brake fluid reservoir (it is the same between clutch and brake), only to find a very soft pedal.

I tried a normal bleeding process with two mecanics, one on the pedal, one on hte slave cylinder bleeder. It was worse.

I tried to do a reverse bleed with a syringe, not working.

It was very confusing.

After some internet searching i found out that the clutch bleed is recommended to be conducted from below using the brake system.

You should pipe the front right bleeder to the clutch slave cylinder bleeder with a quite long clear soft pipe. I bought mine in a fish shop.

Then you proceed with a brake bleed in order to push back the brake fluid from the front right brake to the slave cylinder up to the master cylinder then the the cluth (but also brake fluid) reservoir.

After several days of work it was working again.

I then took well earned holidays.

Today i came back at the SLC.

It started right away after several weeks.


I know i have a small exhaust leak (new gasket are in the glovebox) and i i also remove the center box and change it to custom straight pipes.






I made some adjustment on the ignition timing.
And made a idle adjustment using the air screw.



Now i have regain all the engine revs.


I will finish my testing soon to verify if the timing adjusment had an effect on the cold start or on the general engine behaviour.

Hi Sylvain,

that is good news ! Good that you have finally fixed all your troubles. When it comes to ignition: Start wtih dwell and then adjust igntion timing at 3000/min and finally verify at idle and 1500/min according to workhsop manual. Last check vaccum adjustment.