Hi everyone have a strange problem with my 496 HO..
Having stripped it down to its last nut and bolt and completely rebuilding started and ran fine but only at idle due to not being in the boat, after fitting I took it out for a sea trial and everything seemed to be fine then there was a slight tapping noise and I returned to port..
First thought it was a fuel issue but after further inspection I found that three rockers (two on the right bank and one on the left) had jumped off the push rods, or the nuts worked themselves loose then the rocker was moved.
My questions are my engine is 2001 with very few hours I purchased it from someone who blow up one of his engines and then the boat wasn't used but had some slight moisture issues hence why I rebuilt the engine.
I have to confess I didn't change the valve springs nor the hydraulic lifter as I dismantled them and cleaned them and looked to be fine. The push rods are new and NOT bent so now I'm thinking it may be a oil delivery issue with the lifters or maybe bad valve springs or poor nuts holding the rockers..
On re setting them today I moved the nuts to another place to see if I could see if its the nuts or something else..
Took the boat out and after a short time the noise returned (slight taping) so I went back to port..
Any suggestions would be really appreciated..
Tomorrow I will again take off the rocker covers and find out if the nuts have moved from where I put them or the same cylinder as it was today (with different nuts) has come loose again..
I have tightened the rockers up removing the back lash then a further three quarter turns on each nut to nip them up..
Does anyone know if I'm being correct using these settings??