I
went round Machine Mart and bought an engine stand for £28. The engine was
bolted to this using some M12 x 100 bolts. This bit of kit really makes the
job a lot easier. Next I jet washed the block and then dried it out.
The
various bits were laid out: crank, pistons, con rods, bearing shells. Some
of these are numbered, a bit of time with the Haynes manual sorted this out.
The
first job was to build up the engine with the old bearing shells so that I
could work out how much piston to skim off. The picture shows the bearing
shells in the block. The centre one is also a thrust bearing. ie: it stops
the crank from moving sideways. It took me a while to work out that the
Haynes manual was correct with regards to the thrust bearing. The old shells
were all cleaned and smeared with new engine oil. Once I'd sorted the
bearing locations out then I managed to tighten all of the bearings and get
the shaft to turn. 
I
fitted one of the new pistons to the no1 cylinder. The piston rings were not
fitted at this stage. As my measurements had suggested, the piston did
indeed stand proud of the block at TDC. Rough measurements showed that it
was sticking out by about 0.5mm.
Scraping
manky old gasket off the block was next. A surprisingly satisfying job.
In
order to check my compression ratio calculations I bought a cheap 2.0 8v
engine so that I could take it apart for measurements. I found that both 8v
and 16v pistons protrude above the block by about 0.6mm when at TDC. The
picture on the right shows a new 16v piston and an old 8v piston. Careful
measurements by filling the piston bowls with oil from a syringe and
CAD
modelling of the parts showed that the 16v piston had 2.5cc less volume,
enough to take the compression ratio up from 10.5:1 to 11.2:1. To remedy
this I had an extra 0.8mm machined out of the 70mm bowl of the 16v pistons. 
Another
problem was that the 16v block has some sort of restrictor fitted to
the main oil gallery where it feeds the head.
Lightened
flywheel and stack of bits ready for assembly. 
I
still wasn't sure about what to do with the flow restrictor bung fitted to
the 16v block but not the 8v. So I tapped it out, screwed a bolt into out
and hammered it out using a lump hammer and a small spanner under the head
of bolt. When I laid the 8v gasket on top of the block I was a bit concerned
that there was only about 3mm of gasket in contact and the metalised part
was over the void of the larger hole. I did wonder about cutting that bit of
the gasket out and replacing it with the part from a 16v gasket. 
Shells,
mystery bolt and SBD oil pump.
This
shows the 8v and 16v gaskets. The only differences are: the kidney cut outs
in the 8v gasket, the larger oil feed seal on the 16v and minor differences
in coolant feed holes. 
An uprated oil pump was fitted. It contained SBD cast gears since the sintered items can break at high speed. An SBD Nylon pressure relief valve was also fitted. The standard item can stick. The pump was packed with grease to aid priming on first start up. A later metal gasket was used along with Vauxhall Black Sealant.
I
had the alternator pulley lightened and the PAS pulley machined off.
On
the left: all the gaskets and seals, now identified with some help from the
MIG forum.On the right: the oil flow restrictor plug, removed fo allow an insert to be machined to replace it.
The
oil insert fitted. Old feeler gauge blades used when fitting the rings.
An
oil temperature sensor was fitted into the oilway plug nearest the pump.
This cost £3.20 from Raldes.