Broken rocker

[King Argosy]

Hi can u please help me i broke a exhaust rokker arm tip on a isx cm570 sould i take te head of to inspect valves or should it be fine just to replace rocker arm .thanks

[Lonestar10]

how many miles on the head? could be it broke because it got to tight due to valves creeping up into the head.

[King Argosy]

Only 730 000 km

[King Argosy]

I did overhead 2000miles ago if vale is not stuck it mesures the same as all the others should it be ok to try and start it .only code is for inlet manufold temp high

[Lonestar10]

730k km soo around 500k miles... last overhead was done when? and did you do it so you know it was set right? most shops arent even capable of putting a lugnut cover on right.

im not sure you have to pull the head off maybe replace the rocker and bar the engine over a few times and check for interference and watch that valve to make sure its moving up and down properly.

roughly what rpm were you running when this happened and were you into a full accell or an engine braking at that RPM which is where the most stress on things would be

maybe even find someone with some timing wedges to make sure your cams havent slipped out of time.

exhaust valves get the hottest and grow the most if the overhead wasnt right and was to tight that could be the issue. for every 100 degrees on a peice of metal it grows about 1/1000 of an inch and that can cause issues if a .027 set it done but the valve grows .010 at full throttle and the valve has wore into the head .017 theres a recipe for disaster.

[King Argosy]

i just came down a steep downhill jakes full on into a trafic cyrcle low rpm started misfireing i pulled over and truck shut off , ill replace rockerarm and bar it over to see if valve move and return thank do i need to reset enything its a Freightliner and i think it derated

[Rawze]

should also boroscope it to ensure the valve did not touch the top of a piston, and that is has evenly set valve-seat wear.

how much boost does the engine make?. and how much boost pressure is there during high engine braking?.

[King Argosy]

Will do thanks

[King Argosy]

It boosts 0.8 bar uphill and 0.5 bar on jakes