Caterham CSR Trackday toy: Engine upgrade - part #5

2012-03-05

The head is back, ported nice and smooth, valve seats refurnished and the old valves grinded.

Refurnished valve seats

Smooth inlet

Valves, springs, retainers and cotters

Put back the old cam followers and installed the new camshafts.
Measured cam to valve clearances "lash" with feeler gauges. According to Cosworth the clearance should be inlet 0.22 – 0.28mm and exhaust 0.27 – 0.30mm for my cams. They were all off since the refurnished valve seats made the valves to sink deeper into the the valve seats. To be sure I moved around the old buckets and remeasured several times, but the readings were not that consistent, and some clearances was too small for even the smallest feeler gauge.
Eventually I had a complete list of the sizes I needed with 13 new buckets. A few of the sizes was more or less guesses, so I was prepared to order a couple more later on. Finding a retailer with the buckets in stock was not easy, but to the rescue was SBD Motorsport who had them shipped within a couple of days. Cosworth also had them in stock, but to quote someone well known in the business - "nothing is fast from Cosworth other than their engines".
Meanwhile I fitted the head back to the block with new ARP studs and a new gasket. No problems but I was really close to drop a washer into an oil gallery.. Phew..
Doh! Measuring lash before attaching the head to the block was a bad idea. Some of the measurements have changed (and some was more or less guesses to begin with). A new order to SBD, luckily the delivery was only a couple of days.

Finding TDC using a pencil and a dial indicator

Caterham CSR Trackday toy