CR bluetop EU

[jamiemirror]

dreja Wrote:What does it mean to make a dry build ? To build the engine and to mesure the clearance before starting the engine ?

http://www.guy-croft.com/page12.html (if you cannot open this, just read that description:

Quote:Put the head dowels in place and use a gasket of one type or another, this is the colourful beauty from the latest Federal Mogul Payen set - which is massively better than the ones they supplied a few years ago. If you don’t use the dowels the results will be completely meaningless. I use Plasticine (modeling clay) in the valve cutouts (reliefs) to check the vertical and radial clearance. It is necessary to grease the valves or they will simply pick up the clay when u turn the engine over. This particular engine had 3A cams (it is Ben Ellis’s 2 liter Spider) and u can see that the valves don’t stick out that much at tdc, however closest proximity with some cams is NOT tdc but might be anywhere between 15-20 deg after tdc on the inlet, (cannot remember on the exhaust) as the valve is opening faster than the piston moves away.
You simply put the clay in the reliefs, fit the belt and turn the engine over very carefully two revolutions, then measure the impression. I look for 100 thou“ vertically in the plane of the valve axis, and 60 thou radially. If you don’t get any impression at all, put more clay on the piston till you do - the valve could be hovering over the edge of the cutout. You can also get an initial impression of how much radial clearance exists by just offering the head up with the valves loose-fitted and simply pressing the valves into the pistons at tdc.

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