Here's a quick rundown of whats going on...

208,000 miles.. always ran great my father bought it new, babied. It has never been apart, never been overheated. It started leaking oil pretty bad from the valley, I put it off for a few thou miles always kept an eye on level. In the last 1k miles it started ticking, not too bad, but ticking. So i recently bit the bullet and changed out my valley pan, front cover gasket, oil press sender etc... when I had it apart I took a whole day to really clean the motor while I had the oil pan off etc.. it looked like it had 3lbs of coffee dumped in (carbon sludge and buildup..) I put it back together new timing chain kit plugs everything.. started great! Ran better than I can remember, lifters pumped up smooth idle awesome!!! Except... when it finally gets to temp the oil pressure light comes on sometimes, when I raise the revs it goes away but doesn;t readily come right back on, but it will eventually. A few minutes of this then it starts ticking again, ticking goes away after 1500 rpm runs strong throttle response is sharp.. what could be going on??

Wrist pins?
Liner issue?
Did I mix up my rockers left to right?
Here's a sound clip.

 

Cam lobes?

 

Could be your oil pump. Get a pressure gauge on it and see what it says. It sounds like many other RRs I've looked at. I went to auction the other day and looked at a 98 with only 128k miles, it sounded just like that. My Jag started giving me low oil pressure warnings, you probably already did this, but cleaning the sump catch screen really helped it out.

 

At your mileage, the cam, lifter or any part of the valve train along with the oil pump and timing chain can all be shot.

 

Sorry, new lifters, and updated rocker arms too. I did disassemble the oil pump to clean and remember a ton of wear, should have replaced it. Easy to rebuild and get at. Next project. I'll report on my findings. I am ordering a kit today.

 

May find this, and an oil psi test would also point to it. Cracks make the tick, and cracks let psi be enough to turn out light - for a while, but not enough PSI for proper operation.

 

How do I open my trunk manually? 98 RR