When I wanted to do this there was a lack of complete info in one place so here is a write up. Please let me know if anything is incorrect or if there is a better way to do anything. This is the first time I have undertaken anything involving the timing belt. This is written for people such as myself who are learning- is a basic outline and more detail where the BGB lacks. This was done of my 1990 JDM GT4 engine in car. A lot of stages are included in the engine section of the BGB so any details should be found there.
You will need a good quality socket set (prefer half inch) and a small shitty old one came in handy for small spaces where a real one would not fit, a feeler gauge and micrometer if you need to replace hence measure shims. Useful but not necessary- an inspection mirror which can be extended, extendable magnet and a torch. A selection of different shaped 10mm, 12 and 14mm spanners would help and take photos all the time + label all bolts you do not recognize easily. Most bolts are very hard to get to with engine in the car so many different tools and creative ideas may be needed.
I got a set of 2 3SGE cams for $15 each. They both had distributor notches so the guy must have run an intake one as an exhaust. Note that an exhaust cam although the same size will not work as an intake cam for this reason. Mine were from a 92 MR2. The only differences were the two unusual square notches protruding from the shaft near the dizzy end, the lack of timing notch and were otherwise identical to the celica ones, aside from the larger cam lobes of course. From what I can find the duration is 244 instead of our stock 236 and lift is 0.3-5mm more. The lobes are visibly larger.
First off anyone hoping to do this should have little trouble getting to the first pic. Basically remove, IC, throttle body, ignition leads, valve cover, alternator belt, you will need to remove the engine mount which is shown in BGB before you can take off- upper timing belt cover (this has five bolts of which one is set into the middle (BGB EM pg 21). One point I did not know much about is jacking up the engine. You should put the car up on jack stands and have an extra jack under the sump. It will make removing engine stay (attached to mount) very easy (with a breaker bar) and you can raise/lower the engine over a 4 or so inch range to get at certain things better.
I did this whole procedure with the power steering reservoir, belt and line in place which made it extremely difficult- you may wish to remove them- BGB. Line the crank up at top dead center (TDC)- see BGB 0 mark not 10 mark on lower timing cover. Before anything else get whiteout (twink) and place 3 small dots on the timing belt and cam gear so you can line it up later since you are not removing the whole belt. I and others on the board only recommend using the intake cam only not he exhaust as well due to overlap and overheating issues. Exhaust cam is not warranted with the ct26.
Remove the belt tensioner (2x 12mm bolts) You may find it necessary to remove the engine mounting bracket. It has 3 bolts (2 under the lip and one down by PS belt) and is the most difficult thing I removed. Slip belt off intake cam gear. I tied the belt around the exhaust gear with string to hold it in place. Get an adjustable wrench and place over cam hex inside cover to hold it in place. I then got a 14mm spanner and 1.5 meter pipe over it to remove the cam gear bolt instead of a SST where ever the hell you even get them from- toyota said they had to be ordered from japan. BGB to remove cam-explains everything. You will have to loosen 3 bolts holding that metal sheet on the end of the head so you can place a 10mm spanner over the closest cam bearing cap.
Perform everything in reverse. When installing tensioner you can try jacking it into the car (read on MR2 forum) but this seems potentially painful and not a good idea, I screwed it down fairly easily using a 5 inch clamp and stuck an allen key through the hole. Everything should be torqued down to the specified number as per BGB but this is not possible most of the time due to torque wrench not fitting so as tight as you can with spanners etc most of the time.
I found the cam I put in did not have the notch on the inside of the valve cover on the other side of the cam gears so could not be used for setting the cam exactly but if you only removed the intake cam and marked the spot on the gear it wont be needed anyway. Check cam lobe clearance when lobe is facing upwards. Use feeler tool, should be 0.15-025mm I think. If not you will need to replace the shim with one of the correct size - see BGB. I did not need to replace any old ones when I installed the new cam. You might as well measure the exhaust ones while you are at it (0.2-0.3mm)
You may want to replace the gaskets around the valve cover if they are looking like crap. I painted mine while it was out. And the results.........engine goes and sounds great- probably due to cleaning all the shit out of head. I have not driven it yet since I was blocked in by 4 cars down the driveway, will do so and post results.