5 replies to this topic

[Chewy]

Hey Everyone

I am going to have to put some new valve guides in my ported 12G940 Head my dad says that years ago that he used to put the head in the oven and the valve guides in the freezer and then pull them in the head with a long bolt and a metal plate will this work


Many Thanks Chewy

[vasi]

That's the basic principle of interference fit mechanics, yes. If you're confident, give it a go. I would be inclined to hand it to a machine shop though. You tend to find that replacing the guides often positions the valve ever so a slightly different, requiring the seats recutting.

[Chewy]

Many Thanks

Why do the seats need recutting for

Edited by Chewy, 20 May 2007 - 05:56 PM.

[Bungle]

the guides will also need reeming out after being pressed in

[pondlife]

The seats will require re-cutting because there is no garantee that the bore of the new guide will be in the same place as the guide you have replaced, so the seat could be off set slightly, also depending on how worn your old guides were you could now have an oval valve seat!, at work we charge £4 to fit a guide and £4-£6 per seat to re cut, this includes honig out of the guide to size.

[Chewy]

Thanks

The old guides are not that worn when i took out the valves i am goin to ream the valves on my dril press with a new tool i got yesterday


Chewy