Club 80-90 Forums

I have just been stripping down a pair of Amc heads that I managed to get hold of for my MV build. There is very little pitting on the mating surfaces and no cracks between the valves which is great However The valves all have chewed up collett grooves some worse than others. To start with I thought this was a result of poor quality valves but on careful checking The colletts seem to meet before they are tight in the grooves. This must allow movement between them and the grooves enough to chew things up!!! I have reused the colletts on a set of german valves but have had to grind the mating surfaces to give a small clearance when in position on the stem. Perhaps this could be the main cause of issues with these AMC valves? Or perhaps a mixture of soft valve stems and loose colletts? The valve heads themselves and the seats were lovely, Hardly any lapping was required just enough to make a good seal , no pits to grind out !!!

Marco Mansi builds a lot of WBX with AMC heads and he says ( on FB) valves are cheese.

there may be movement causing it but it still means the valves are useless.

[img]https://farm5.staticflickr.com/4368/36167856674_babb9b6e00_b.jpg[/img]AMC Valves 2 by Paul_Barr, on Flickr