What I've learned in the last few years from experience.
I have a 2010 F150 with variable valve timing (VVT) systems on the 4.6 3valve engine. Keep in mind, Every engine design IS different The engine was noisy when new. I have gone thru 2 sets of Phasers in 140,000 miles and two timing chain kits. To be accurate, Had one kit that Cloyes sold me that the tensioner exploded under warrantee, sending shrapnel thru the engine requiring dropping the oil pan and vacuuming what I still could still find. I cannot comment on this matter here
I have a Subaru with 178,000 miles now I did the timing "set" Belt tensioners water pump and belt with a supposed high quality Meets or exceeded OEM spec kit from amazon. Within a year the belt broke the tensioner seal was weeping and I now had to replace the bent valves. A very expensive proposition. I purchased a 5 star Bernie OEM kit and replaced it again. The engine was never the same because of oil consumption issues that M1 5w30 E. Performance mostly helped correct. My point. Belts maintain timing almost exactly for life where the chain has many wear points in the system, can be noisy (to be fair a belt is noisy in its own way as well). Even without VVT its complicated with and OHC engine maintaining the chain geometry. My opinion is Belt replaced with all pulleys and tensioners and water pump, And if the cam seal are questionable change them ((Subaru seals are arguably normally good well into the 150,000 to over 200,000 mile range), per the manufacturers recommendations using Aisin premium, 5 star Bernie, or better yet a exact set of Subaru parts and forget about it again for another 105,000 miles. Same on any other brand unless the OEM is junk which I seriously doubt. I don't trust any other brand and some will disagree and that's fine. an OEM lasts 105000.
I have a 2010 F150 with variable valve timing (VVT) systems on the 4.6 3valve engine. Keep in mind, Every engine design IS different The engine was noisy when new. I have gone thru 2 sets of Phasers in 140,000 miles and two timing chain kits. To be accurate, Had one kit that Cloyes sold me that the tensioner exploded under warrantee, sending shrapnel thru the engine requiring dropping the oil pan and vacuuming what I still could still find. I cannot comment on this matter here
I have a Subaru with 178,000 miles now I did the timing "set" Belt tensioners water pump and belt with a supposed high quality Meets or exceeded OEM spec kit from amazon. Within a year the belt broke the tensioner seal was weeping and I now had to replace the bent valves. A very expensive proposition. I purchased a 5 star Bernie OEM kit and replaced it again. The engine was never the same because of oil consumption issues that M1 5w30 E. Performance mostly helped correct. My point. Belts maintain timing almost exactly for life where the chain has many wear points in the system, can be noisy (to be fair a belt is noisy in its own way as well). Even without VVT its complicated with and OHC engine maintaining the chain geometry. My opinion is Belt replaced with all pulleys and tensioners and water pump, And if the cam seal are questionable change them ((Subaru seals are arguably normally good well into the 150,000 to over 200,000 mile range), per the manufacturers recommendations using Aisin premium, 5 star Bernie, or better yet a exact set of Subaru parts and forget about it again for another 105,000 miles. Same on any other brand unless the OEM is junk which I seriously doubt. I don't trust any other brand and some will disagree and that's fine. an OEM lasts 105000.
