I finally took both heads off and sent to Richard Sedoris. Below is some of his analysis. I should have them next week. Dean ...........
The heads look good. I glass beaded the ports and chambers and found no cracks. On the head that had the old valves in it I saw the wear on the keeper grooves. Seemed to be more prevalent on the intake valves, but there was wear also on the exhaust keeper grooves. This type of wear is usually caused by mismatched and/or poorly manufactured valves and/or keepers. If the fit between the keeper and valve is loose the valve stem grooves will wear as the keepers move up and down on the valve. The new valves and hardened keepers have a good fit, but I would like to take it one step further. What I can do is grind the keepers so the ends do not touch. This basically "locks" the keeper onto the valve. The valve job on these heads was one of the worst I've seen in a long time. The valve size is 40x35, but these were giving you no more performance than a stock set of heads, If not less. The problem is how the valves were sitting on the valves seats. Instead of sealing on the middle or outer edge of the valve these were all sealing on a thin .010-.020" area at the narrowest part of the valve seat. The diameter of this area was 36mm on the intake and 32mm on the exhaust. When I regrind the seats I will take advantage of the full valve head, increasing performance and longevity. The guide to valve stem clearance wasn't too bad, but the intake guides were out of spec. The exhaust guides are perfect. Usually you see the opposite, exhaust wear before the intakes do. But I imagine due to the issues with the valve stem keepers the valves may have been side loading the intake guides and causing excessive wear. -- Visit the VintagVW archives at http://mail-archive.com/[email protected] --- You received this message because you are subscribed to the Google Groups "VintagVW - Air Cooled Volkswagen Discussion List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/vintagvw. For more options, visit https://groups.google.com/groups/opt_out.
