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Old 01-27-2024, 10:52 PM
cfoss cfoss is offline
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Join Date: Nov 2023
Location: Vancouver Island
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Well I spent another interesting day on the bmw.

I did a leakdown test on the engine just to confirm it's all ok. I set both banks to max valve open just for fun. I cranked each cylinder to 80 psi. Here are the results:

Cyl 1 76
Cyl 2 76
Cyl 3 76
Cyl 4 77
Cyl 5 76
Cyl 6 77
Cyl 7 76
Cyl 8 77

So, very very good in other words.

Then I had an idea on how to check the valve lift mechanism: Rotate the engine so that the intake cam lobe is at max and then rotate the valvetronic motor from the valve closed stop to valve open on each cylinder and see if they are similar.

The way I did this is to use the leak down tester, set to about 20psi input. This is not enough to rotate the engine, but is enough to determine when the valve opens.

I have read that the valves will be open a tiny bit even when the lift is at minimum, but my valves are closed at the minimum stop-so the test worked.


Here's a vid of how I did it:

https://www.youtube.com/watch?v=eQ0ptrnwz5A

The four valves were very similar:

Turns before open:

Cyl 5: Crack: 1.5, Open: 2.0
Cyl 6: Crack: 2.0, Open: 2.5
Cyl 7: Crack: 1.5, Open: 2.0
Cyl 8: Crack: 1.0, Open: 1.5


So it seems the cylinders are pretty synched. Looks like mechanically the valvetronic lift mechanism is fine.

Onward....

Next up, I'm going to check that the cams are still in time with the engine with the allignment tool. I expect that they will be fine, but while I'm here I may as well eliminate that possibility.


Chay

Last edited by cfoss; 01-27-2024 at 11:01 PM.
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