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John,

Can happen by cranking too much. Then I would recommend to change the oil. Or first, to make a compression test on each cylinder, to be sure that all piston rings are ok. Could you identify the colour of the dust ? Is it burning oil ?

Hi Murat,

Compression is good! In fact engine when running sounds / feels lovely... The engine has only covered less than 60 thousand miles...

This is probably my own fault of over cranking....

I am trying to upload pictures to my photo bucket account, but have such limited Internet strength here in the Highlands.

Will try and get photos to you...

Saying this, I had a good run with her yesterday, to the garage to check for the mot .... Opened her up a bit, had a bit of a. Cough and splutter... But since then she seems to be fine... Holding idle and everything!

Still not 100% as I feel at points carburettor just want to open up too much. :-/

Best

John

I had also a run today. Starting well, but idle is rough and still very dusty, but it holds it. Driving with throttle is no problem. Accelerating well. And no suspicous mechanical sounds. One ore more rockers are getting a little bit louder when the engine heats up. Tomorrow, I am going to check valve adjustments again.
It drives me crazy really.
Chocke flap works properly, it is full opened when the engine is hot.

Hi guys,

Today, I have made a compression test. Please see the results. Maybe I should have done this earlier.
I am just wondering about these results. To my experience, there is always one or two cylinders which are bad.
But these are all bad, and each cylinder nearly with the same result ? How can this be, this is very curious.

Please note: engine was not in operation temperature, only a little warm, and my tester is over 30 years old.
Looking for each possible reason, maybe I have assembled the valve springs reverted, etc. don't know what else could be happened during assembly.
Awaiting your comments and ideas.
Greets
M.

I'd say you had leaks or perhaps didn't test with wide open throttle. But the valuaes aren't far apart and that's what matters most I guess, this gives me the idea the compression won't be the problem as usually with compression problems you have one or two cylinders staying behind.

Any other views?

Yes Jeroen,

I agree, there is something curious. Throttle was full open. Temperature was like hand-warm, not operation temperature. There came no fuel blown out of the other spark plug holes. It seemed to be very "dry" to me. Though the car starts easily but still very dusty. All 4 spark plug were black dusty. So, I really don't understand this situation anymore. Normally, you have one or two faulty cylinders. Is there a common problem which I don't see ?

M.

Still sounds like massively over fueling, or incorrect ignition timing. I'd first do some measurements, but perhaps Peter has a word or two to add as well...

Thanks Jeroen,

I am using the 315 dizzy transistor type. I thought many times of it. If I compare the stock data of 315 and 320, both have static ignition time at 3° before TDC and dyamic at 25° before TDC at 2300 rpm. Same dizzy with same number is also used in 318i with 1,8l and 105 HP. So, I am really not far away.

Overfueling: the electro magnetic idle valve, is it permanently supplied with 12V ? And the electric bi-metall starter, has this also 12V permanently ? Or are they triggered by the temp.sensor ? Maybe I have a fail in the sensor ?

Murat

This depends.

Can you place a picture of your current carburator. The 32/32 DIDta can be with an extra electric item mounted at the side of the carb, (a thermoswitch).

Normally you will have power at the mangnetic idle valve when you turn the key. The bimetalspring gets power as soon as a temperatureswitch gets to 45°c. Then it may open the chokevalve. But there are constructions that it will start opening at 17°c. So therefore it is important to know what kind of electric schedule you have.

I am wondering if the problem is not the combination of your 315 camshaft and the setup of the engine and carb to a 320. I do not have al the data but can it be that the valveopening height is wrong (read to little or to much).

I understand that you have to change the camshaft to the 315 because you want to use the ignition of the 315 (electronic).

To add something extra to your compressiontest. Could it be that the reading was so bad because you have a high amount of black coal in your cylinders and valves?

Thanks Peter,

Temperatureswitch: I have both possibilities, I can connect to the 315 switch from the water hose front, or I can connect to the original 320 switch under the manifold (like at the moment). Chocke flap is opening completely when engine warms up. Seems to work.

Compression test: yes, there can be a lot of coal now inside. The head was cleaned completey before assembly.

Camshaft: as far as I know, all stock M10 shafts have same timing and opening heights. For example, when you by a new shaft you can only choose between turning the dizzy left or right.
Example, if the timing is really different, maybe this would explain, why all results of the compression test were identically bad. Who can compare this data ? Anybody to share ?

Hi guys,

New update. Today, I have changed the whole ignition system. I thought to eliminate some other errors. New coil, tsz trigger and dizzy from 518i. For the tsz, it was overdue, some stuff was drained out. But no changes, same effect again.
Dizzy fits to camshaft and all M10 have iginition point at 3deg before tdc static and 25deg before tdc dynamic at 2300 rpm.

Also checked my M10 spare camshafts. I have measured 315, 320/4, E12 520 and E30 316i which I have. They have all the same measurements.

Timing marks of camshaft and crank are still ok. No sounds from the timing chain. Oil and water are still clean. Now I am thinking of the pistons. Has anybody a picture from the 320/4 pistons Euro carb version ? Would be helpful. I just want to check if the pre owner has installed different ones. And I am going back to the fuel supply of carb. It must be something which affects all cylinders. I will post some pics in the next days.
M.

Guys,

Some new information in this issue. I have changed all ignition parts, cap, rotor, cables and tsz trigger module. And also tried a spare dizzy.
Engine starts immediately, but again with very rough idle and black dust. Removed the spark plugs, and all four were dusty again. I have driven the car around the block and it was misfiring and stuttering. Too rich ?
Then I shut the idle solenoid valve by pulling off the cable. There was no reaction to it. It was still on idle for man y minutes. As I understood the function, it should cut the fuel idle line when 12V is off. So the engine should stop immediately when shutting it of ? Could this valve be my reason for the engine's bad running ? Can somebod try it ?
Greets
Murat

I have found another point which makes me curious. When I search the internet for the acceleration diaphragm, I always find this picture. It should have a ball inside. But mine doesn't have this ball, which function should the ball have ?
I have also found a picture of the pistons. This was made a few months ago, when I built up the engine. Can somebody take a look on it please ?
Information: the engine came from a E12 carbed with double Strombergs. It was in assembled and original condition.





M.