So what goods to get?

By Clinton HulleyVW Polo Classic Project Car
Trolley with parts
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Deciding what you want to build is the most difficult part. Do you run standard con rods, what pistons to use, what power and torque levels are you aiming for. Do I fit parts to protect for future upgrades? You start sitting with all these ideas and you have to get direction.

Forged Conrods or not?

My plan was just to build a stronger more reliable setup. What I had was running really well until the point I took everything out. I was looking around for ideas and come across a website www.MrTurbo.co.za. They were selling forged con rods and the prices were really good. I decided there and then that this is an upgrade I want to do. This will protect me with future upgrades. I am building an engine now and don’t want to open up the engine later for upgrade con rods. I did not want to stand the chance of losing an engine because of a weak con rod.

These conrods looked the part! The next step was to decide what pistons to use and what size. I wanted to run a really big bore piston. I went for the Nissan CA20 piston which was a flat top 84.5-millimeter piston. This is 2 millimeters bigger in Diameter than the standard 82.5-millimeter pistons of the Volkswagen 2E 2.0 liter engine. So the CC’s per cylinder would increase from 496cc to 520cc. This made the total CC of the engine increased from 1984cc to 2081cc. That is approximately a 4.7% increase in volume and more volume equals more power and torque. As the gudgeon pin of the CA20 piston differs from the Volkswagen piston. New Small end bushes were fitted to the con rods and machined to suit the CA20 pistons gudgeon pin.


Will these pistons fit on the conrods?

There is another issue that has to be sorted out when fitting the CA20 pistons onto Volkswagen spec conrods. The CA20 piston is a press-fit piston. This means there is no groove for a circlip like on the Volkswagen pistons. I had to design a plastic-type of an end cap to put in the ends of the gudgeon pins. These end caps are called buttons. They are made from PTFE material so they have a low wearing capability and they would outlast the engine. I had the buttons turned on a CNC lather to ensure they all weigh exactly the same.

What to do with the block?

The next job on the list was to get the block sorted out. I got the block bored and honed out to suite the 84.5mm CA20 pistons. I also got the engineering shop to fit new intermediate shaft bearings and to line bore them. Now I knew this block is as good as it could be.


How does this shaft run?

While I was waiting to get the block back from the engineering shop. I had a look at the intermediate shaft that came with the engine. The shaft was in good condition. I took the shaft and put it in a lathe to clean up the bearing liners. But was shocked when I switched the machine on. Because this was a cast shaft the shaft was jumping around. Between lathe centers the bearing running surfaces were straight. The rest of the shaft that was not machined did not look so good. On a normal production car that doesn’t spend a lot of its time at higher revs. This may be acceptable but for me, this would just not do.

I took this shaft and started machining it down till the overall thickness of the shaft was 15mm. The shaft really looked good and had no run out on it. I could just imagine myself what loading there must be on standard shafts with all the runout. After I machined it looked like this.

Do what with the flywheel?

Stuff now really started coming together. I next had to decide what clutch I was going to use. I am not a big fan of button clutches. They are most of the time like on/off clutch. Some people like to say digital clutches. I decided to go with a standard Sachs Clutch. We had a lot of success till now with them and they are really good quality. I wanted to lighten the flywheel so that the engine would be nice and quick-revving. So I put the flywheel in the lathe and machined the back weight of the flywheel. I also opened up the inside diameter of the flywheel to suit the inside diameter of the clutch lining.

Now I had all the parts so I could get the balancing done on the rotating parts. As the conrods were forged rods they all weighed the same. It was only the pistons, crank, flywheel and clutch pressure plate that had to get balanced.


I almost had all the parts to start building the sub-assembly. I went to Goldwagen and bought a new sump, windage tray, Elring gasket kit, main bearings, big end bearings and a new Schadek oil pump for the engine. Now that I had the parts now the fun could start…..


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