[Healeys] Stainless competition valves

[Andy Thorp]

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.


--------------------------------------------
On Thu, 11/12/14, Michael Salter <michaelsalter at gmail.com> wrote:

 Subject: Re: [Healeys] Stainless competition valves
 To: "Niels Bengaard" <bengaard at 850r.dk>
 Cc: "Andy Thorp" <bce257 at yahoo.co.nz>, "healeys at autox.team.net"
<healeys at autox.team.net>
 Received: Thursday, 11 December, 2014, 8:48 AM

 Hi Andy,
 Before making a decision on the
 material for your guides I would recommend reading this:
 http://www.netbug.net/blogmichael/?p=384
 You may get
 away with it but, you may not.
 Unfortunately
 the consequences of a valve seizing in a guide can be
 catastrophic and I see no good reason for taking the risk
 when cast iron is a perfectly satisfactory material for
 valve guides which will provide years of service without the
 risk of seizure.

 Michael S
 BN1 #174