Can anyone tell me if this is normal?

[PeteMelb]

(09-02-2018 )Chamberpains Wrote:  A lot of the cm870 and cm871 air compressors knock\rattle while building air both new and old compressor's. The timing can be lined up perfect and all. Then stop once the governor kicks out. Its sounds like a definite engine knock. Its normal on an ISX. They just knock when building air. Are you sure your not chasing a perfectly normal air compressor noise?

Hi Chamberpains, thank you for your reply, I wish it was that simple, I have dealt with a few of these motors and know the compressor knock well, but this is not that unfortunately, it's way to solid a knock I spotted a run of soot from the manifold join today on the newly painted motor so Im really leaning towards an injector at this point, as soon as I can get back to it I'll post what I find when I find it.