- Joined
- Oct 15, 2007
- Messages
- 14
Ok. So I've tried the search engine and can't find anything that really covers what I'd like to know.
After stripping down the head on my Commando I found that one inlet valve spring seat (cupped/dished washer) has a groove worn in the centre that matches the inner valve spring diameter perfectly. It's worn a ring in it .034" deep. Not something I would consider a good sign by any means. That particular spring was also showing signs of wear, well, smoothing of the spring face. I decided to replace the springs with new ones from Norvil which arrived yesterday. The new valve springs look great, but unlike most other new valve springs I've seen, the ends of the spring which seat against the spring retainer and spring seat aren't a nice smooth machined/ground finish. The have some fine marks in them, almost as if they where ground/cut to size with an abrasive cut-off disc. The engine has a Combat head fitted but still runs the original cam. I was thinking that due to the inlet valves not having the heat insulating washer under them the lack of tension may have been letting the spring chatter to some extent, but after seeing that the original springs also have this rough face surface I began to think that maybe that surface in itself was causing the spring seat wear.
Is there any merit in polishing/lapping these spring surfaces to a mirror smooth finish? Could that have been the cause of the spring seat being worn or would the lower spring tension (missing heat insulators) be a probably cause? Maybe someone with more experience in rebuilding these engines can shed some light on this for me.
Here's a photo of the new springs. It's not supremely clear as my digital camera doesn't seem to like close up shots sometimes.
Kenny
After stripping down the head on my Commando I found that one inlet valve spring seat (cupped/dished washer) has a groove worn in the centre that matches the inner valve spring diameter perfectly. It's worn a ring in it .034" deep. Not something I would consider a good sign by any means. That particular spring was also showing signs of wear, well, smoothing of the spring face. I decided to replace the springs with new ones from Norvil which arrived yesterday. The new valve springs look great, but unlike most other new valve springs I've seen, the ends of the spring which seat against the spring retainer and spring seat aren't a nice smooth machined/ground finish. The have some fine marks in them, almost as if they where ground/cut to size with an abrasive cut-off disc. The engine has a Combat head fitted but still runs the original cam. I was thinking that due to the inlet valves not having the heat insulating washer under them the lack of tension may have been letting the spring chatter to some extent, but after seeing that the original springs also have this rough face surface I began to think that maybe that surface in itself was causing the spring seat wear.
Is there any merit in polishing/lapping these spring surfaces to a mirror smooth finish? Could that have been the cause of the spring seat being worn or would the lower spring tension (missing heat insulators) be a probably cause? Maybe someone with more experience in rebuilding these engines can shed some light on this for me.
Here's a photo of the new springs. It's not supremely clear as my digital camera doesn't seem to like close up shots sometimes.
Kenny