this ones lasted 3000miles... I doubt they are stock, or someone put the wrong ones in.
I doubt that they wore out in 3,000 miles.
I suspect the guys that put it togather are a couple of hacks and delivered it screwed up.
Kind of makes you wonder if you should take it back to them to fix, they my not be capable...
or an inferior valve guide... magnesium would last a long time 
magnesium?
Are you thinking Managese Bronze (CDA 863)? Known as Mag Bronze, Its good for heavy loads at low speed.
The stock Bronze valve guides are actually top notch, it used to be an upgrade for the US built engines to go to bronze valve guides from their POS iron guides.
I don't know what the stock guide alloy is. Befor we condem the stock guides right straight to heck, maybe we should find out what the alloy is. It could very well be mag bronze all ready.
My job involves working with (and knowing, to a certain extent) allot of different alloys.
u mean manganese? i heard that some of the old aircooled motors used magnesium guides or something like that.. and they never wore out. could have been manganese bronze though...
Yah, manganese bronze. I know alloys, can't spell them though. :oops:
The aircooled valve guides are bronze too, so I would guess the material is the same.
I did get the head fixed by the place that rebuilt it. It was covered by warranty. They replaced all the guides and looks like they replaced all the exhaust valves. Their diagnosis was that something got into the head and broke out the guide. That's hard to believe with no entrance wounds on the piston, and no exit wounds in the turbo. My guess is that a bent valve stem wore the guide down to nothing. Whatever the case, there are about 400 miles on this rebuild, and the last 200 miles the oil consumption was next to none.
