There was a low end knocking, very typical of rod bearings. So I took it to a garage and had them remove the oil pan, and have a look. They confirmed that the rod bearings were worn.
I decided that to save some money, it was a do it yourself job, so I set about getting prices for parts.
You can replace rod bearings with the engine in the car, but if the crank is bad, it needs regrinding, and oversized bearings are then used. So I removed the engine. This took about 2 days total. I was working on this in my driveway, and mainly I only had saturdays to work on it.
After removing the engine, I put it on a stand, spun it upside down, and removed the oil pan. I inspected each of the bearings, took a good look at the crank journals, and inspected the main bearings too.
The crank was badly worn on two journals, and the main bearings were worn too, so I decided that it was time for a reground crank. Advance Auto Parts sell a crank kit, that contains a reground crank, and a set of matching rod and main bearings. It is $180 if I remeber correctly, and it saves a lot of fuss.
At this time we had a lot of rain, and it was forecast to continue for a couple of weeks, so I sent the engine out to have the crank installed. This cost $150 from a local mechanic. I had him put on a mew water pump and timing belt at this time, because the belt had to be removed anyway.
I got the engine back after a couple of weeks, and began the re-installation process. Putting the engine back in took another 3 days work. Lining it up with the transmission was the hardest part, and bolting up the exhausts to the manifolds was difficult becasue there is hardly any room to get the tools in there, but apart from this, it was just very time consuming.
I was somewhat surprised when it started on first try (after turning over without fuel or ignition to get some oil pressure) I was anticipating a non start, or a rough idle or something, but it started first time, and ran just as smooth as ever.