I'll weigh in on the noise issues!

I too am amazed at the various noises the B23/B230 can make. More amazing are the varying levels of noise. First, I take into account that the basic design of the engine is anything but new. It's certainly a little agricultural in construction and in comparison to newer engines, I don't think tolerances and such are as tight. If you are used to a 90's or later, all alloy engine, where huge consideration was given to noise reduction and smoothness, then certainly our 4-bangers (emphasis on banger) are noisy and rough. On your timing belt noise, I don't find it unusual for a new tensioner to "whir". If it is doing so too loudly, you may have overtightened it. That said, I have had the belt itself make noise from being too loose. I'm not certain what the exact harmonic is, but it may even be noise generated by the movement of the belt when it is not snug--teeth actually churning air. All I know is that upon removing some of the slack, noise went away. Don't disregard the possibility that your rear chain cover may be warped, causing contact or vibration. The most common thing I read about the engines is the "diesel" scenario. Since the sound is usually represented as being mid to low range, I rule out valve train noise. I think what most people are hearing is piston slap. Most of the time I find this is related to engines that see very little long distance driving, lots of short trips, or are never revved very high. What I think we have in these cases is filthy, sticky ring packs that don't seal very well. Power is usually down. I highly recommend Auto-RX to clean out such gummy problems. I once went as far as to use a remedy from 70 years ago: ran the engine with a combination of kerosene and hydraulic oil for an hour (no load) then drained it. The mixture was black and soupy when it came out. Other things to check carefully for hum/whir sounds would be anything with a bearing. Keep in mind that all of the accessories are mounted in rubber (or urethane if you've upgraded the bushings). To do the timing belt, you probably removed all the accessory drive belts. There's no chance that any single belt went back with exactly the same tension. Thus, if any of your accessory bushings are worn, you now have an accessory which is sitting at a different angle. Thus, the pull on that item's bearings has been changed. As long as the bearings are in top shape, no problem. However if the bushings were worn and the accessory was being driven at an angle, the bearings took a "seat" in that position. Once you move everything, the bearings are wearing differently. I suggest you use a stethoscope to check near the bearings of your various accessories (PS pump, alternator, water pump, AC compressor). If you don't have one, use the old mechanics trick: get a long screwdriver and seat the handle in your ear. Probe around with the end sitting on various surfaces until you locate what's humming. Sometimes resting your thumb on the end of the screwdriver and putting the joint into your ear helps. Take a good, sidelong look along the front of your engine. Site along the belt paths. With care, you will be able to see if one of the accessories is not sitting parallel to the crankshaft line of the engine. That's the one to start with.

Dave