Regarding valve seat recession.
I very much doubt that it will ever be a problem in a Healey engine.
Check this http://www.netbug.net/blogmichael/?p=623
Michael Salter
http://www.netbug.net/blogmichael/?p=445
-----Original Message-----
From: healeys-bounces@autox.team.net [mailto:healeys-bounces@autox.team.net]
On Behalf Of Bob Spidell
Sent: Friday, October 02, 2009 8:59 AM
To: Paul Leeks
Cc: healeys@autox.team.net
Subject: Re: [Healeys] Octane ratings
Depends on what you mean by "better off." In general, you can use the
lowest
octane-rated gasoline that prevents engine knock (the rattling noise you'll
hear
under load--e.g. lugging or climbing a grade--if the octane is too low).
Knock--aka detonation or ping--can be very damaging to an engine over time;
an
occasional rattle probably won't hurt. Some Listers get by with regular
87-octane (R+M/2), some--like me--use premium (in CA, that's 91 R+M/2). Or
you
could split the difference and use mid-grade. Make sure your timing is set
and
advances correctly, then try the two (three) grades. Unless your engine has
higher than normal compression, premium with no additive will probably work
just
fine; esp. if your static compression is at/under 170psi or so.
Protecting the valve seats is a different topic. Under normal driving, it's
probably not going to be an issue; exhaust valve recession has proven to be
less
of an issue than originally thought (ZDDP anyone?). You can throw in a
bottle
of 'lead substitute,' though I wouldn't bother and just plan on pulling the
head
and installing hardened seats and alloy valves if/when they start to leak.
BTW, you get no "boost" from using higher octane gas. The energy content is
actually higher in lower octane gas (it burns faster therefore releases a
stronger 'explosion'). You only need the higher octane to prevent
detonation in
higher compression engines (which do give you a boost).
bs
Paul Leeks wrote:
> I wonder if I can get some advice re the type of petrol for my BN4.
>
> Over the last ten years I have used standard unleaded (Octane 95 RON)
along
> with Castrol Valvemaster Plus which claims to provide an octane boost. (I
> have non-hardened valves/seats.)
>
> So my question is ... would I be better off using super unleaded (Octane
97
> RON) plus the CVP or will this make me 'over-boosted'?
>
> Many thanks
>
> Paul Leeks
> BN4
*******************************************************************
Bob Spidell San Jose, CA bspidell@comcast.net
*******************************************************************
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