Skoda Rally Blog

… So there have (typically) been many delays. But I’ve drawn up a schedule and I’m sticking to it, and this weekend’s task is to get the new engine built up. After all the delays with parts and machining, etc., actually putting the thing together is a reasonably fun task. First up, fitting the crank to the crankcase – only 6 bolts and fitting the bearings, but getting it all checked took an hour or so (checking all the clearances means it needs to be fitted more than once), and the end result was a crank that turns beautifully.

Next up, fitting the pistons to the conrods, which means fitting some very annoying wire circlips, a couple of which were a real pain to get in, but eventually they were done, and then the rings onto the pistons. The rings are standard Skoda items which is very handy, and they fitted without trouble. Having done many engines before, I had a piston ring compressor already, so getting the pistons into the bores is easy – plenty of oil makes it slide in without trouble – and then it’s just a case of fitting the shell bearings (which have been checked for clearances) and torquing up the big end caps. Four of these takes a while though, but the end result was a bottom end that turns as freely as you can expect for a freshly-built engine.

Next, some measurement and calculation – firstly checking that there was good clearance between the pistons and the cylinder head – the standard head is flat and the Group A one has machining to accomodate the domed pistons – which wasn’t a problem, but means fitting a head gasket, putting plasticene on the pistons and then fitting the head, and turning the engine over. Clearance between pistons and head was fine, so no problem there, thankfully.

Now, some measurement – for completeness’ sake, measuring the compression ratio, which involves measuring the volume of the piston crown and the combustion chamber, which takes a sheet of perspex, some water and a burette.

The end result of today’s work?

Now, the pistons are a source of some issues – I have been told by a reputable tuner that they are complete junk, and I should go for forged pistons (which would cost around ?800 or so). Aside from anything else, I don’t have the money to do that at the moment, but the manufacturer says they’re good to 8500rpm (and I’ll only be using 7200), and I’ve heard other reports that they’re OK, so I hope they’ll be fine, but I guess I’ll only know when they’re in the car and running. We’ll see…