Friday, January 16, 2009 - 09:41 am, by: David Ormsby(Phoenix)
Matthew, as I understand it:
Valve guides = metal (sometimes inserts) in the head in which valve stems move up and down.
Valve seals = little rubber cup things with metal band to hold them against stem to prevent all your oil dropping into combustion chamber.
When the seals get older they go hard and can crack/shrink etc. I've used the stop smoke type stuff in a 3SFE which had slight cold start smoke and it did seem to make a difference, though this was right around the time I sold the car so don't know how it's getting on now but checking carjam they've clocked a further 60kms.
so don't know how it's getting on now but checking carjam they've clocked a further 60kms. 
