Compression Testing a Rebuild before install
 

I found this video on Youtube... does this actually work?

http://www.youtube.com/watch?v=7LWqC...eature=related

If it does work how accurate are the readings?

Yeah, all you really need is a bellhousing and starter attached.

Yep. I just did this. You can get a cheap, remote, push button starter from Harbor Freight or Matco or someone and it is easy...in particular when you have a compression tester.

You should note on a FRESH rebuild that compression builds up over the first few hundred or thousand miles.

Try not to over think the compression testing process. Whether the engine is in a car or on a bench, you only need a strong battery, a good starter attached to a bell housing, and a compression gauge with the strader valve removed to check the compression. Also if you don't have a gauge handy, all you need to do is listen for 3 even pluses out the exhaust ports for each rotor housing.

When I build motors, I simply turn them over by hand to make sure I'm getting good, strong compression pulses. You can hear the engine "whoosh" out of the exhaust ports. If that's doing it, the motor was assembled properly.

Real compression numbers are almost impossible to tell on a 0-mile engine, it does need miles to break in before you get to what the final compression numbers will be.

Dale