Guess what's wrong with my motor..

[ORCoaster]

High pressure in #1 carbon or valve related.  Low in #2 is trouble as not very balanced across all 4.  Perhaps a bad seat on head for either or both valves.  Otherwise the 480 is spec on new motor.  Gain likely due to oiled rings the second time?

[masterbeavis]

Update:

I reran compression. I allowed 5 revolutions on a cold motor. 

450
380
420
440

Before putting it back together I cranked the motor for a while to see how the lifters pump up. 3 are weak, over 1/8" deflection.  I put it back together as-is, still had the knock. This time I cracked injector lines once running to isolate the offending cylinder, put in another injector, the noise went away!  It does not run right however. It's low end torque is gone, you can feel the misfire. I need my injectors gone through and lifters.


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[libbydiesel]

A stuck injector sounds just like a rod knock.  

Compression test should be done on a warmed up engine and the number of revolutions DOES NOT MATTER.  You should keep spinning the engine for a given cylinder until the pressure no longer rises on the gauge.  That's usually a heck of a lot more than 5 revs.

[masterbeavis]

I've ran the compression test 3 times on this motor, twice cranking till the end of time and getting the first two set of numbers. I'm not going to warm a car up with a suspected spun bearing to do a compression test. If I was doing the test wrong, the numbers cold are still high enough to convince me the motor was worth fixing.


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[8v-of-fury]

He is not telling you to run the engine to operating temps, just merely that a proper compression test is done warm is all.

[masterbeavis]

Will a warm motor give better or worse results?


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[ORCoaster]

I believe that warm is better results as expansion of all parts means higher numbers.  Cold is leaky.