Need some help with my R32 GTR

[Benanas]

Hello my name is Ben and I'm new to this website and forum but I am in search of help finding the problem with my 1991 R32 GTR. Back in October the head blew out a coolant path and had to be removed and welded and fixed so cylinder 6 would not have coolant draining into the cylinder. It worked and was put back on the car with new metal gaskets from a tomei gasket set and a slew of other new parts like a Kevlar greddy timing belt, new water pump, new exhaust guides in the head, all new rubber hoses all over the engine bay(because the others were 28 years old), new mishimoto radiator,  new tensioner, tensioner spring, and along with other small things all over the engine bay. During the process of having the head off he cleaned all the throttle bodies which he then found out from someone that builds rb's that he shouldn't have done that(not sure why). When it was all said and done and put back together my mechanic didn't want to give the car back until he looked into a sound coming from the engine bay at idle. It sounds like a whining or whiring sound if you will. It cant be heard when moving but at a stop and idle it can be heard quite loudly in the car and standing outside of it. My mechanic thinks it might have something to do with the throttle bodies being cleaned but is not sure. The car runs and drives great(better then before it broke). He is not positive what the sound is and asked all his other mechanic friends in the area and had them listen to it and they weren't sure or 100% on what it could be either. Just hoping someone could help me out. My initial thoughts are the Kevlar belt making the sound because it is tighter and doesn't have as much give but I'm not sure. Attached is a video of the noise. Clip isnt very long but it gets louder if you rev it up to about 2k and then it quites down a bit. If you have any ideas please help me out. 

[Benanas]

Also is this something i should be worried about or is it just going to be something thats there or maybe might work itself out? I was assured it wasn't anything crazy and the engine wouldn't be damaged from this sound production but just want to check if anyone else has had this problem or something similar.  I know its hard to judge it just from description and a short clip but anything helps. Here is a link to it in youtube form if the .mov doesn't work.

 

[GTSBoy]

Use a screwdriver or hammer handle as a stethoscope to isolate where the noise is coming from.

Yes, aftermarket belts can and do make different noises. That sounds a bit unpleasant. There is no such thing as "tighter" with timing belts. There is only the "correct" tension. If someone has added a bunch of tension to the belt, consider not doing that.

[Benanas]

19 minutes ago, GTSBoy said:

Use a screwdriver or hammer handle as a stethoscope to isolate where the noise is coming from.

Yes, aftermarket belts can and do make different noises. That sounds a bit unpleasant. There is no such thing as "tighter" with timing belts. There is only the "correct" tension. If someone has added a bunch of tension to the belt, consider not doing that.

My bad. I was under the wrong impression. Timing is not something I fully grasp among other things. In your opinion do you think this could have to do with the timing belt? Like i said i understand its hard to really tell form a few second clip but the timing belt and the tensioner pulley and spring were replaced and that would be my main guess as to where the sound is coming from but im not too mechanically savvy to make a detailed guess. 

[GTSBoy]

I don't know. I gave you a helpful instruction to try to work out where the noise was coming from. Go have a poke around. You might learn something. If you tell us, we might too.

You can also use a short length (like 500mm) of garden hose or similar. You put one end in your ear and put the other in various places. If the noise is coming from under the inlet manifold, then the diagnosis is likely to be very different than if the noise is coming from the timing cover area.

[djr81]

Remove the belts driving the alternator aircon water pump etc and have another listen.

[Old man 32 GTR]

There is a product called throttle coat, look it up, I believe the throttle bodies are coated from factory, if this coating has been removed when they were cleaned it makes a slight whistling noise. This could be your issue. You touched in this in your first post so you’ve obviously been made aware of it. It will be a pain to rectify as your plenum will need to come off again to fix if (if that’s the problem) 

[Old man 32 GTR]

Kudos has it in stock 

[MoMnDadGTR]

mine had a whining from the front of the engine(93 gtr). I ended up replacing timing belt,water pump, tensioner, and pulley. whine went away car ran like a dream no noise.  make sure if you end up tackling it yourself you read lots on the job.  its not that hard but takes time the first go around. and get a proper puller for the crank pulley so you don't damage it.