mattman1234

Was speaking to a cylinder head "specialist" the other day,was going on about my head leaking oil into the ports,and its only done 5000 miles ish ,blah blah.Anyway he was saying it could be a bad install of the guides,and this could cause oil to leak into the ports,and if this was the case the head would be scrap,as we were talking on an exchange basis for mine.Is this true,i'm guessing the oil seeps down between the head and guide.Am i right in thinking the guides are just pressed in.If so,could you put an "O" ring around the top of the guide,then install the spring plate,therefore making a seal between the guide and head.

tabetha

The guides are indeed pressed in but not "just" pressed in.
Usually with it being alloy head the head will be heated, and the guide frozen to aid fitting, that's how mine were done afaik, but mine were COLSHIBO, as it doesn't wear.
The faces of the valve seat are cut using the guide installed as a reference.
It's very hard to get the guides wrong, but I think your person is trying it on, even if someone managed top put them in off centre, a alloy plug would be put in and then re centred to reclaim the head, by drilling from scratch.
All I can suggest is use someone you trust, the guy that does my machining is not the cheapest around, but is 100% honest, if the head is scrap he will tell you, but he won't lie, if you have the head done with colshibo guides it will never need doing again.
I'm more than happy to take your head to the guys I use if you want, and post it back once done, just pm me.
I don't want anything just the postage cost back that's all, even though it is a 60 odd mile round trip for me.
tabetha