The Fast Daily – A C5 Allroad Story – Part 5

Finally got back to work on the car. Delays at the machine shop plus a vacation meant I couldn’t work on the car for a few months.

I was hoping to re-use the stock pistons, but the bores were worn way past spec, so I got a new set of Mahle 9:1 81.5mm pistons. What’s another $1000 anyways?!+

I mated the pistons to some CX-Racing H beam rods and ARP rod bolts. For anyone using the same ARP 200-6220 bolts, without a stretch gauge, I found that almost all of the bolts reached the proper stretch at 31ft/lbs – 1 ft/lb higher than ARP’s specs.

I chose to use ARP main bolts so that I could measure the main bearing clearances accurately, without having to use a sacrificial set of TTY factory bolts. I know there’s been some conjecture on the torque spec for ARP mains – I went with the ARP spec of 100 ft/lbs and had the mains line honed. My machinist said that the journals were minimally distorted and just needed a light kissing.

For anyone thinking about building an engine, get a piston ring compressor specific to the bore size you’re working with. Yes, you’ll have to purchase one per bore size, but they only cost $30 and they’re so much nicer to use than a universal piston ring installation tool. With a machined piston ring compressor you can just push the pistons into the bores by hand – you don’t even need to use a mallet.

I didn’t think it was necessary to replace the oil pump chain, but I couldn’t find just the tensioner by itself, so I ended up buying a new chain and tensioner ‘kit’ from Febi, part number 33750.

I got as far as the oil pan. Tomorrow I’m going to install the heads, manifolds and turbos.