[Corky_91]

Hi All, first time posting on this forum!
I have a 1993 R32 Skyline GTS-T with RB20DET and I'm in the middle of doing a timing belt and water pump replacement.

While troubleshooting some issues with the tension of the timing belt (engine sounds like it has a super charger), a worrying knocking/tapping noise has developed from what i think is the valvetrain/head area. I'm quite worried about this as its appeared out of nowhere and hasn't happened on this engine before apart from the first second or two after cold starts.

I've heard that some noise from the lifters is common on RB engines under certain conditions, but this coupled with the work being done on the timing belt, removing spark plugs etc has me worried.

Some background:
The car hasn't been run up to temperature and driven around in over a month, the car has been jacked up at the front for about a week and its been really cold here lately.
I'm running a 10w50 oil but this hasn't been a problem before at these temps.

I've uploaded a video here which might help identify the noise. The supercharger whine can be ignored as thats looking likely to be an over tensioned belt or one of the belt bearings.

I'd appreciate any help in identifying if this is an issue or something that will go away when the engine warms up! Thanks

 

[Tricky-Ricky]

How long have you been running 10w50 in this engine and what mods have you got? It's very likely that the hydraulic lifters are not pumping up properly due to the high oil viscosity especially at the low temps at the moment, I would not recommend running anything but std viscosity unless the engine is running much higher power as it puts very high strain on the oil pump and its drive which is not ideal and also puts oil seals under more pressure.

 

[Corky_91]

I've been running 10w50 for over 2 years now. The engine is making 330bhp - HKS GT-RS turbo, bigger injectors, front mount, full exhaust. The engine itself is standard.
I haven't heard this noise from the engine before. Is it possible that the thicker oil combined with only idling the car around the garage for several weeks has contributed to the oil draining out of the lifters?

I'd also like to ask that you're not hearing any more serious noises such as bottom end knock in this video? I was just guessing that it sounded like top end noise.

 

[Tricky-Ricky]

Personally I would not run anything more than 10w40 at that bhp, all higher hot viscosity does is slightly increase oil pressure and add to pump stress, anyway I can't hear anything other than the lifters and injectors, but video is not ideal for picking out engine noise.

 

[Corky_91]

Hi Ricky, i changed out the 10W-50 for some 5W-40 Petronas Fully synthetic that i had going spare. The noise disappeared straight away and it was only 1 degree Celsius outside.

Thanks for the help! Ill stick with a 5w40 or 10w40 in future.

 

[Tricky-Ricky]

No worries...glad it's sorted.