[Healeys] Stainless competition valves
Bob Spidell
bspidell at comcast.net
Wed Dec 10 14:53:44 MST 2014
FWIW I have bronze guides--intake and exhaust IIRC--in my BJ8 (stock iron head). They've got about 100K miles of hard road use on them; no issues whatsoever.
I believe the main issue is getting them reamed correctly; think they do expand a little more and if they're reamed too tight they can carbon up.
Bob
----- Original Message -----
Hi Michael,
Thank you, this is precisely the issue. Bronze is great for aluminium race car
heads but it doesn't have the longevity for 100,000 mile OEM road use, nor the
thermal expansion compatibility for cast iron.
Early stainless valves did not have hard enough stems to work with cast iron
and tended to gall quickly, so they had to use bronze guides. The more modern
ones have hardened stems to prevent galling and I can't tell whether the
Healey ones are properly hardened or not.
It seems odd that AH Spares would sell valves that are not suitable for most
applications without actually stating that on the website. I'm hoping that
they are mistaken and that the plasma nitriding they claim the valves have on
the stems makes them hard enough for cast iron.
Andy.
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