Does Anyone Ever Reuse Valves?

[jluetjen]

I was checking the valve stem diameters on the superset of intake valves that I'm hoping to use on my race engine and without exception they all seem to be undersized. They almost all came in at about 8.95 mm when I measured them at location "B" a shown in the spec books (a little further out towards the tip then location "S" as shown on page 211 of Wayne's book) versus the spec of 8.97 - .012. One came in at 8.92 which is obviously junk. When I measured them closer to the tip or closer to the head (similar to location "S" in Wayne's book), they were all smaller still which is what I was expecting.

The curious thing is that I checked 8 valves (6 from the core 2.4TK and another couple that came with my S heads) and NONE of them appears close to salvagable. Is this unusual or normal?

As it stands now I'm going to need to shell out for all new valves. Ugh!

[ChrisBennet]

Hi John,
I send my heads out to have them done and the machinist decides if the valves are good to reuse. Sometimes they are reusable, sometimes they are worn or past their "use by" mileage. I had some once that he advised me to change because they had over 100K miles on them even though they were within spec.
He told me that on other motors (water cooled) the valves last a long time but for some reason, 911 valves/guides have a shorter life. He theorized it was due to the extra heat.
-Chris

[TimT]

John, funny you should ask....

I send my heads out to a west coast guru to be rebuilt. When he calls back with the estimate we talk about whats worn and what needs replacing, Then he asks about the intended use of the engine...if a race engine and you can stand some smoke on start up dont touch anything. If its a street engine and your embarrased about a big blue fart once in awhile when you start the engine you should replace some things.

Valve stems are really hard, they hardly wear, Valve guides are soft.. they wear first.

If the valve seats havent been ground too far into the heads, and the valves themselves still show a three angle finish, you probably can still use them....

I reuse valves....... In my engines current iteration, I have probably 50% new valves.... only because I bent the valves on half the engine. The surviving valves checked out ok....

its all IMHO

[Wayne 962]

You might want to talk to Walt at Competition Engineering - he might have undersized valve guides...

-Wayne