valve installation question

[BLOHS7844]

I have the head off my engine so it could be resurfaced (long story) but none of the valves are bent or anything. They all held water too so I know they sealed. Can they just be put back on the head as is or do they have to be reground? I have all the valvetrain components separated as far as intake and exhaust go.

 

[BogusSVO]

Lap them into the seats they came out of, install new seals. ( I would suggest a new set of valve springs at this time too of you have the old stock ones)

 

[BLOHS7844]

Awesome thats all I was wondering. I thought I would have to lap them. I'll look at some of your write ups and see how its done. and got new valve stem seals. The car has about 125K on it so would new springs be necessary? I won't be going past the redline at all

 

[BogusSVO]

For about $85 for a set of BC1100 springs, I would install them.

Think of it this way, how many times have those springs been compressed and released in 125K in 16 years?? Think they may have gone a bit weak by now?

http://www.dsmtuners.com/forums/articles-engine-fuel/341636-how-lap-valve.html

 

[BLOHS7844]

Another quick question... I scratched the outside of a couple of the valve guides when removing the seals. Is that an issue?

 

[BogusSVO]

On the od of the guide? No that will not be an issue

 

[jakeb2011]

In my material science class we learned all valve spring are made to never reach there fatigue limit under cyclic conditions. Springs being used in unintended rpm range could slowly work harden the spring and cause it to become brittle and lose its ductility. If used under that limit they keep their properties and could be repeatedly loaded over and over. Long story short non abused valve springs could be used for 100's of thousands of miles if used under the conditions that the manufacture intended them too.

 

[BLOHS7844]

Ductility only refers to deforming under tensile conditions and for a material to fatigue, it doesn't have to reach its ultimate tensile strength or even its yield strength. Also I think a harder material would exhibit a stronger resistance to compression as a spring. Real materials tend not to obey ideal rules that are only used as examples or estimates.