After removal of the heads for the injector sleeves to get replaced I found one broke valve spring.and. I noticed 3 of the 6 pistons have a couple lil cracks. Hairline deals...that normal or I need to replace them.. its a recon engine..ran great.
That is common for a high hour engine. The cracks will continue until they reach the Ni-Resist insert that the top ring is in. The crack will eventually burn through or a chunk of the piston crown will come off sometimes with parts of the insert. Does a huge amount of damage.