OVERKILL
$100 Site Donor 2021
Originally Posted By: BrianWC
When this thread was originally posted, I was just 20 days past buying a new Si with the k24z7 engine. Within the lifespan of the factory fill, my cam lobes looked the exact same way. I've since run heavier oils, usually a franken-mix of whatever I have on the shelves of my aging stash, and the cam lobes have not gotten any worse. So perhaps the cams are allowed to get those lines on the very outer surface but nothing beyond???
I've similarly run whatever oil was closest in my '02 CR-V for probably ten of the eleven years I've owned it (ran M1 5W30 the first) and it's still motoring along.
It is completely normal for there to be a "track" where the roller follows the lobe (in a roller valvetrain application). You won't be able to feel it with your finger, but its presence is expected given the finish on the lobe itself after it has been ground. As the lubricated wheel acts against the slightly irregularly finished surface, the surface becomes less irregular and these "tracks" are just the result of that.
Depending on how shiny the finish was on the lobe when it was made will determine how visible this characteristic is.
To demonstrate how harmless this is, I've had the valve covers off a Modular that was extremely low mileage (my buddy's 02 GT) and where the roller followed the lobe was visible. I also had the valve covers off a Crown Vic with north of 400,000Km on it at the wreckers and it had the same tracks. No better, no worse
Even in applications with much higher valve spring pressure (relatively speaking here) like my 302's, the 2nd of which had the factory cam in it until ~312,000Km, the finish on the cam was "like new". But you could still see where the roller lifters followed the cam profile on the lobes.
When this thread was originally posted, I was just 20 days past buying a new Si with the k24z7 engine. Within the lifespan of the factory fill, my cam lobes looked the exact same way. I've since run heavier oils, usually a franken-mix of whatever I have on the shelves of my aging stash, and the cam lobes have not gotten any worse. So perhaps the cams are allowed to get those lines on the very outer surface but nothing beyond???
I've similarly run whatever oil was closest in my '02 CR-V for probably ten of the eleven years I've owned it (ran M1 5W30 the first) and it's still motoring along.
It is completely normal for there to be a "track" where the roller follows the lobe (in a roller valvetrain application). You won't be able to feel it with your finger, but its presence is expected given the finish on the lobe itself after it has been ground. As the lubricated wheel acts against the slightly irregularly finished surface, the surface becomes less irregular and these "tracks" are just the result of that.
Depending on how shiny the finish was on the lobe when it was made will determine how visible this characteristic is.
To demonstrate how harmless this is, I've had the valve covers off a Modular that was extremely low mileage (my buddy's 02 GT) and where the roller followed the lobe was visible. I also had the valve covers off a Crown Vic with north of 400,000Km on it at the wreckers and it had the same tracks. No better, no worse
Even in applications with much higher valve spring pressure (relatively speaking here) like my 302's, the 2nd of which had the factory cam in it until ~312,000Km, the finish on the cam was "like new". But you could still see where the roller lifters followed the cam profile on the lobes.