Cause Of Low Oil Pressure On New Low Km Engine?

[HRthirtyone]

ok, so i cracked a piston in my old rb20. Just went out and purchased one from a front cut, seemed in really good nick, put it into my r32, slapped my 550cc inj, and my hks2530 on, and went and got the microtech tuned. everything seemed fine, the motor ran really smooth. - did notice oil pressure a tad lower than usual, but still good.

after getting it tuned i drove it to work and back a few times, not really thrashing at all. the other night, went for a hard run up through the hills, and noticed a REALLY loud lifter noise. had to pull over and check it out.

on idle it was sitting around the 15psi and even less mark on the oil pressure gauge.

the next morning i checked oil level properly, it was nearly full, and the lifter on no 3-4 intake side sounds like it is broken, its not your usual lifter "tick" its more like a "rattle"...

anyone got any ideas on the possible causes ??

[blind_elk]

I thought the same sound in my old RB20 was a sticky lifter. Then someone bought the engine and stripped it down; turned out the cylinder was suffering "piston slap".

[r33_racer]

maybe you need to pull this one down and inspect the pump...maybe the backing plate is coming loose as some do and its dropping oil pressure.

[HRthirtyone]

ok, the oil pump is at the front of the engine behind the harmonic balancer isnt it? sorry, havent replaced an oil pump on an rb before.... ive pulled my old one apart but didnt take much notice of it, was more concerned about other things!