Friday, August 16, 2013

Leak Down Test

German "Inception"--fine German engineering inside fine German engineering.  Is your mind blown?
In order to determine if my BMW's engine is any good, I needed to test it.  The other option would be to hope for the best and just build the bike and see what happens when cranking it for the first time.

Since it is not in any position to crank, a compression test is out of the question, so I had to do a leak down test.  If you're not familiar with that test, like me a short time ago, you basically pump pressurized air into the engine and see how much leaks out and where it leaks out.  The images below show the tester and the concept in cartoon form.

Ideally, an engine will have less than 10% leakage.  Up to 30% is probably acceptable for street engines.  My left cylinder had 40% and my right had 100% (gulp), mostly through the exhaust valves.

Verdict:  An engine rebuild is in my future.  It's only time and money...

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