RB25 engine whine, cant figure it out

[180sxLove]

I have a S1 Rb25 that started making a high pitched whining noise that was only apparent when you would rev up the motor. It seemed to resonate from the front area so I removed my accessory belts and the noise was still there, googled Rb25 engine whine and everything led to timing belt.

I pulled my timing cover and noticed the belt was a lil old, so i ordered a new OEM one, including tensioner , spring and idler. I enthusiastically replaced the timing belt , made sure it was not over tensioned, got it all put together and the noise WAS STILL THERE when i revved the car up :\

it starts at around 2300 rpm till red line. sounds like a loud supercharger whine

last night i spent my night googling and reading old Australian skyline threads and again the internet led me to timing belt, so i decided this morning to undo everything again, retensioned the belt (by turning the crank by hand until the tensioner spring set a decent tension), put it back together and the noise WAS STILL THERE :\ I ran the car without the top timing cover and visually the belt was perfect. the noise is not there at all in idle.


at this point i have no idea what to do next., i dont think it has anything to do with the timing belt.

I also dont think its my tranny either, the noise is there whether clutch is pressed in or not, neutral or in gear.

i'll upload a video very soon. i wanna figure this out

[s13silvia123]

I had this problem for a long time on my SUV. i did all of that and i found out my alternator pulley was bad then also found out that my Crank Pulley was the main cause of that whine. check that out.

[180sxLove]

https://www.youtube.com/watch?v=tmSxdmHXmpE

I started the car up for less than 30 seconds without the water pump hooked up so don't kill me plsssss



However sound wise its there whether car is warmed up or not, makes no difference. hope someone can lead me in the right direction

[dbeiler]

It's difficult to tell from the video but the noise seems to be a metallic rattle instead of a whine. If it really is coming from the front of the engine, the VCT cam gear could be a suspect. Has the cam gear ever been removed?

If you don't already know, the CAS should never be bolted straight to the CAS bracket. Washers/spacers must be used to replicate the thickness of the front timing cover gasket which has been removed.

[180sxLove]

Sorry for the double post

[180sxLove]

Originally Posted by dbeiler

It's difficult to tell from the video but the noise seems to be a metallic rattle instead of a whine. If it really is coming from the front of the engine, the VCT cam gear could be a suspect. Has the cam gear ever been removed?

If you don't already know, the CAS should never be bolted straight to the CAS bracket. Washers/spacers must be used to replicate the thickness of the front timing cover gasket which has been removed.

I had a few washers in between but probably could of used more, I didn't torque the cas tho just in case.

The cam gears have not been removed since the noise started

[feito]

I would start taking things apart, starting with that vct cam gear, and inspect everything.

[RB25GUY]

you changed tenisoners and idler pulley? sounds like the belt is too tight

[180sxLove]

Originally Posted by RB25GUY

you changed tenisoners and idler pulley? sounds like the belt is too tight

The noise started a few months ago, prior the car was quiet in terms of weird noises.

When I noticed the noise I originally thought it could of been the timing belt being too tight, idler or tensioner bearing going out, atleast based on what I read online, even tho most videos i saw with tight rb25 timing belt had a whining \ whirring at idle as well. Mine only does it when you rev up the car, in idle its quiet. No chirp no squeel nothing

I bought the belt, tensioner, spring and idler new OEM. i didnt reuse

When I installed the new belt i made sure to get a good 1\4 turn on the belt on the long side from the intake cam to tensioner. I turned the crank by hand and let the spring set the tension.

When I started the car up the first time after replacing the timing belt and heard the sound again, I decided to take it apart and did the tension again this time with even more slack. u can even see the belt vibrating its looser than i would want it but for sure enough tension where it will never come off.

The back of my belts dont look like they r rubbing the paint off and im not seeing any paint or rubber marks on the idler or tensioner indicating that its too tight.

Originally Posted by feito

I would start taking things apart, starting with that vct cam gear, and inspect everything.

Before I go and remove the timing belt + more for a 3rd time (which seems inevitable at this point) would you mind explaining why you suspect the VCT cam gear?

[Sforteen]

try unplugging the solenoid to the vct gear see if it changes anything... how does the cas feel when spun by hand?

[180sxLove]

Originally Posted by Sforteen

try unplugging the solenoid to the vct gear see if it changes anything... how does the cas feel when spun by hand?

Just unplugged the solenoid and started the car up, still makes same noise.

CAS feels good when spun by hand, spins freely no weird bearing bind or noise.

[180sxLove]

bump in case there are any new suggestions on my problem really want to drive my 240

[Mitsubayati]

I had a bearing noise coming from the front of my RB and it was really hard to tell where it was coming from. I took a long flat head screw driver with a hard handle and touched the small end to different places on the block with my ear on the big end. It helped me hear where the noise was louder. I found out it was my water pump with this method. I would suggest you do the same or even get an automotive stethoscope and start poking around.

Also as a suggestion, it might be worth taking the intake cam gear off and inspecting it's components.

Also, Please never take vertical video.