Leak down test

[galanos]

Leak down test results:

CYL 1: 9 %
CYL 2: 9 %
CYL 3: 9 %
CYL 4: 9 %
CYL 5: 11 %
CYL 6: 11 %

I hear air sound coming off the OIL FILLER CAP during the leak down test of all six cylinders.

what do you say according to leak down test results with air sound coming from oil filler cap?

[oldz]

every body has an opinion-but here is mine.noise is from a piston ring sealing problem.is the engine broken in yet?if not drive it .this could be related to the way the engine was honed.put a squirt of atf in the spark plug hole and retest.if the engine has been sitting/stored the rings could just be dry.test is very consistant between cylinders.if it has just been rebuilt best bet is to talk to your machinist.if you are breaking it in and are unsure about yor ecm tune dont give it lots of throttle-just put some miles on it if it is tuned well enough to be a daily driver

[Neel]

I agree - drive it and see what happens. Your motors take a beating: 1000hp on an S54! Simply not blowing it up on the dyno every run is an accomplishment!

[galanos]

every body has an opinion-but here is mine.noise is from a piston ring sealing problem.is the engine broken in yet?if not drive it .this could be related to the way the engine was honed.put a squirt of atf in the spark plug hole and retest.if the engine has been sitting/stored the rings could just be dry.test is very consistant between cylinders.if it has just been rebuilt best bet is to talk to your machinist.if you are breaking it in and are unsure about yor ecm tune dont give it lots of throttle-just put some miles on it if it is tuned well enough to be a daily driver

engine is very new.

Car is making good power, compression is good, leak down is good. I am working on a New breather system.

[galanos]

Learnt a lesson: do the leak down test at operating temperatures.

Pushed the M3 with 912 dyno dynamics whp on road, next day leak tested, all cylinders are less than 4 %.

So far the engine is lasting at 912 dynamics whp.

[Neel]

Way to go! Good to hear all is well.