Loud noise/rattle from engine ~2k rpm

[NewKleer]

Was just going to go out to jaycar to get some wiring to fix the missing wires on the computer, when i had my windows down and noticed a strange loudish (might have just heard it with windows up) rattling type noise. It was like the typical lifter tick, but more of a rattle and louder (at 2k rpm i cant really hear lifters in daytime, whereas this i could definitely)

It starts at about 2000 rpm in 1st, and then goes away so its a lot softer as revs get higher. It wasnt easy to pinpoint where exactly it was, but seemed to be in the vicinty of the top of the engine.

I was only about 1min away from home so i drove back. Had this not been worse enough, ive got a friends wedding on saturday that i really need the car to get to

Any easy way to check/rule out certain things, like timing belt, water pump, oil pump, etc? Additionally, ive noticed that in the last month, lifter noise has gone from 1 exhaust lifter to maybe 2 intake lifters (as well as the exhaust one) - Perhaps need a engine flush + oil change?

Thanks in advance

[PLYNX]

Could be the same thing thats wrong with mine. Gudgon pin loose in the piston. Since youve had the car do you know if its over heated at all. If so theres a chance that in dooing so the motor has draged the piston in the bore thus damaging it. Im about to go to a RB30 conversion and I just waiting for it to give up the ghost. Spoke to a very good mechanic and he basically confirmed this with mine

[NewKleer]

actually it has overheated once, after losing about a 1/3 of the coolant due to leaking radiator

the sound is rather minor, certainly not overly noticable, maybe just a tad louder than lifters (about 3 of em are noisy). it seems to only make noise at a given, narrow rpm band (like 2000-2100 rpm, and tends to move up slightly on the revs for each gear i think. normally need to be passing fences or something reflective to hear it most of the time

noticable on backoff, eg if going in 2nd at 3krpm then letting the clutch off ill hear it momentarily as it passes thru its "noise band".

how loud was yours?

[slow_r31]

could be an exhaust leak, the noise band may be resonance.

i had that problem with a noise band of about 100rpm around 2.2k with a leaking exhuast flange

[R3AP3R]

Does the noise disappear when the engine heats up? Mine does similar for about the first one or two minutes in the morning, then it disappears. If I leave it sit for a few hours so it cools down again, the noise re-occurs. The severity and duration seems to vary with how cold the engine is.

[NewKleer]

u mean the lifter noise? i have lifter noise when cold (and still noticable when warm) but its different, and lifter noise is over whole rev range (eg idle too) whereas this is very narrow band.

i should give the car a good drive so i can better determine if it goes away when warm. got the oil/filter changed yesterday, with any luck that may have fixed it, but thats more of a hope then a possibility i think

[R3AP3R]

No mine is in the same narrow rev range you're talking about. Not only 1st gear, but any gear as long as it's the same range. After about 2 minutes in the morning, once the engine warms up it disappears. I'm assuming it's because the engine warms up, but don't know for sure.

If I drive out of my estate at less than ~2000 revs (2nd gear) then it doesn't do it. I've had my oil filter changed a few times since I've had the car and it didn't help me. I'd really like to know what it is, because it doesn't sound healthy, and it's quite loud.

[NewKleer]

do you also have loud lifters? (ive got like 1 exhaust and 2 intake making noise) maybe resonance attributed to them? (although it sounded like it was coming generally from top middle of motor, rather than towards the sides a bit more with the lifters.) if u dont have noisy lifters at all then perhaps something else. has ur car overheated before?

[R3AP3R]

I wouldn't say my lifters are overly loud, and as far as I know the car hasn't overheated. At least not since I've had it (2 years).

[PLYNX]

Peter;

The noise you've described is exactally the same as mine when I first noticed it ! It gets louder over time unfortunatly. Loudest from about 2200rpm to about 3100 and then stays constant. Ive been nursing mine ready for the conversion cause I use my car as a dayly driver.

[NewKleer]

just took car for a drive then, and yes i cant hear the noise once car has been running for about 5-10 mins.

does the noise go away for you when the car is warm plynx?

[PLYNX]

Unfortunatly, no the noise doesn't go away when the car warms up. My cars been that way for quite a few months and I've been nursing the car acordingly. If yours does then you might be in luck and its not a gudgen pin problem

[NewKleer]

thanks - will make me sleep a bit easier at least, but thats no consolation for you. unfortunately with a imperfect head (lifter noise), i couldnt bear anything happening to the bottom end (esp due to it being in a silvia, i cant do an rb30 conv without considerable trouble), so i hope its nothing to do with that.

i read elsewhere that the VVT/VCT on the s14's over makes a weird rattling type noise, any chance it could be a similar thing on the rb25?