What oil and filter should i use?

[Skym]

Any sludge buildup would be due to not changing oil often enough. I change oil on my car every 3 months or 1000km, even though they recommend every 5000km or 3 months.

I use 10W60 as recommended by Nismo. I think 15W50 was racetrack spec oil. I keep it a 10 weight because of the hydraulic lifters and engine likes the 10 weight better.

I changed oilfilter from Ryco to a Repco (Australian company) oil filter. Made in Indonesia.

[ARC240]

Before I built my engine I used to use Royal Purple 10W30 full syn with a genuine Nissan filter for a 91-94 Nissan 240SX (w KA24DE), intervals @ every 1500kms (basically at the begging of the season, middle of the season and right before putting away the car for storage...so every 3 months with exception of during winter storage), the engine was ecstatic, no doubt, absolutely loved it. Can't wait for the day that I can go back to RP ...boo for engine break-in periods LOL.