Freshened up the bottom end new roller cam and springs this winter, all was good I did have what I thought was not enough preload on one lifter. Was out on the weekend cruising on the highway and it started to back fire through the intake and load and it would do it.
Pulled the valve cover to make sure it wasn't a stuck valve, rolled it over all the valves where moving, pulled the plugs and rockers rolled it over no noise,removed the push rods one at a time and narrowed it down to number 6 intake even with the plug out it sounded like it was coming up the intake. Pulled the intake and head tonight and I can't see anything obvious, no marks on the piston thought the chain might have jumped its brand new double roller, lifter appears fine link is intact pin for roller is fine. Pulled the valve there is some carbon on the back side of the intake valve not much and the seat looks ok. Layed a straight edge on all the valves they seem to be the same height any clues?
