Originally Posted By: Finz
Mechanic replaced timing belt Sept '12 with 178,601 miles. Also adjusted valves
This is where you may need to go back too. Some aluminum heads when warm can increase valve clearance not decrease it like iron heads especially engines that use sodium filled valve stems.
Honda having learned a lot from the motorcycle engine may use these, i don't know for sure but i strongly suspect it.
Some aluminum head engines can make scary albeit relatively harmless knocking noises from the top of the engine from excessive valve clearance, be it from adjustment, worn lobes, slippers or rollers and the VTEC system.
knocking from the VTEC unit is also possible and is another long winded post in itself.
Seeing as he adjusted them recently i suspect this is more than worn out or damaged parts.
Knocking becoming more pronounce when warmed up is more likely from the top of the engine. Rods and mains tend to just get louder and piston pins exhibit a sharp double rap.
There are a few other sources of knocking but they tend to remain constant hot or cold, these would include flywheels, tensioner, accessory pulleys, etc. Exhaust manifold leaks have also been know to produce noises that resemble ticking or knocking.
I would at least check the clearances in the process of elimination. If they spec cold then make darn sure its overnight cold and hot work as fast as possible once the engine is shut down, make sure the lobe is really on its heel (aka the base circle), if its off just a few degrees it can cause an incorrect (tighter) measurement.
Adjusting the valves on a VTEC takes patience and it can be difficult to get good feel on the feeler gauges, your engine is easy enough to check and adjust for a DIY job.
Mechanic replaced timing belt Sept '12 with 178,601 miles. Also adjusted valves
This is where you may need to go back too. Some aluminum heads when warm can increase valve clearance not decrease it like iron heads especially engines that use sodium filled valve stems.
Honda having learned a lot from the motorcycle engine may use these, i don't know for sure but i strongly suspect it.
Some aluminum head engines can make scary albeit relatively harmless knocking noises from the top of the engine from excessive valve clearance, be it from adjustment, worn lobes, slippers or rollers and the VTEC system.
knocking from the VTEC unit is also possible and is another long winded post in itself.
Seeing as he adjusted them recently i suspect this is more than worn out or damaged parts.
Knocking becoming more pronounce when warmed up is more likely from the top of the engine. Rods and mains tend to just get louder and piston pins exhibit a sharp double rap.
There are a few other sources of knocking but they tend to remain constant hot or cold, these would include flywheels, tensioner, accessory pulleys, etc. Exhaust manifold leaks have also been know to produce noises that resemble ticking or knocking.
I would at least check the clearances in the process of elimination. If they spec cold then make darn sure its overnight cold and hot work as fast as possible once the engine is shut down, make sure the lobe is really on its heel (aka the base circle), if its off just a few degrees it can cause an incorrect (tighter) measurement.
Adjusting the valves on a VTEC takes patience and it can be difficult to get good feel on the feeler gauges, your engine is easy enough to check and adjust for a DIY job.