jug said:so brass is best for these?
Bernhard said:I can confirm from first-hand experience that the original cast iron guides will outlast any bronze guide.
When I “Dunstallised” my 750 Norton, I fitted Dunstall’s own bronze guides to the head, these lasted less than 15 months compared with the 5 year old cast iron ones, so are NOT very durable and long lasting.
Bernhard said:I can confirm from first-hand experience that the original cast iron guides will outlast any bronze guide.
When I “Dunstallised” my 750 Norton, I fitted Dunstall’s own bronze guides to the head, these lasted less than 15 months compared with the 5 year old cast iron ones, so are NOT very durable and long lasting.
Bernhard said:Dunstall guides were made, if my memory is correct, from Hi-Dural 5 material.
Rohan said:All the reports of Commandos with untouched motors with big mileages under their belt are with cast iron guides.
??
Rohan said:Chilled cast iron comes with the ultimate impregnated 'dry lube' = graphite flakes ...
Thats why millions of engines for a century or more ran unlubed iron guides even, and they lasted and lasted....
kerinorton said:SHIT. When I rebuilt my engine a month or so ago, I fitted 2 new black diamond exhaust valves. As far as I can tell, it still has the original valve guides. Do I have a problem and should I remove the head and change the valves to some more compatible with the "cast iron" guides?
Dereck