m20 valves

[zaq123]

Ok so my original built head is garbage, cracked. Supertech valves in it just got seated as the car had about 1k km when I noticed the crack. Valves have about 1k and have a noticeable line on the valve face where it was seated to the old head. Old head was fully rebuilt and valve seats were cut to 3 angles so obviously seats aren't exactly the same width etc as new head.

I threw in those valves into new head and they are holding alcohol with no leaks. Do I reuse these valves or should gett a new set? I think it's pointless to lap valves here because the face of them is perfect and the contact line ( I assume it's the edge of the valve seat contact) will not be at the same spot once valve under the spring pressure.

[zaq123]

pics. valve with wider face is EX

[digger]

these things are too hard to tell on pictures always looks worse than reality. Whatever donor you use will need work done by a cylinder head place and they can inspect and grind if required

[hasa]

I'd just do proper valve lapping with those and drive happily, unless the plans are to build some really carefully built race engine.

[TobyB]

I'd lap the intakes lightly just to confirm the seating pattern- they look fine.

Either the exhausts are completely carboned up, or have great horkin' divots in them-
Digger's right, that picture looks terrible, but at 1k it CAN'T be that bad.
They look like they've got 200k of wear on them.

So clean them up, and if the face is still flush, a light lap there, too, just to make sure
the pattern and margin is ok.

t
lapping isn't always about the sealing experience...
you can blue them, too, if you can find the bluing dye.
Mine's always missing.