Nice buy on that Accord. Honda has long been known for very good chassis tuning, especially at the price point for which they sell. The K24 engine will last almost literally forever. You can check the valve adjustment in your garage in about 30 minutes (after you let it cool overnight of course). The K24 is very easy to service, very easy to maintain, very enjoyable to own. I don't know if your Accord has a Maintenance Minder on it, but that engine is good for 5k mile OCIs on conventional easy (even 7,500 or 10,000 with UOAs). If you prefer synthetic, you can most certainly go 7,500-10,000 miles. Still, I'd be more comfortable with a UOA to confirm. There are plenty of UOAs on these engines in the UOA forum.
As far as valve/engine clatter when cold, I've found that Mobil 1 0W-20 produces the LEAST amount of noise, cold and hot. Pennzoil Platinum 0W-20 has been the LOUDEST in the engine for me (K24 in a '08 CR-V). I will try PYB 5W-20 next, but if I don't care for that, I'm going back to M1 0W-20.
As you have discovered, the K24 is an excellent engine, even with the tamer "economy" style VTEC. Plenty of power at most engine speeds. Even without the "power" style VTEC, power picks up nicely as you move through the engine's midrange, while still providing enough torque down low so you don't have to keep downshifting. It's a great motor, and the fact that the K-series is still used today demonstrates how good it really was when it was first introduced in 2001.
If you adjust or check the valves yourself, I'd love to see a picture of the valvetrain with the cylinder head cover removed. Did you say you have a detailed service history with this one or not?
