Kevin,
Did your source say what year engines this started?
A BL mechanic told me I didn't have to worry about that with my 72 when they
changed over to unleaded gas here in the States. However, I still put a
lead additive in with each fill up.
Dave 72 B
----- Original Message -----
From: "Dodd, Kelvin" <doddk@mossmotors.com>
To: "Chuck Renner" <crenner@dynalivery.com>; "MG Mailing List"
<mgs@autox.team.net>
Sent: Thursday, January 08, 2004 10:50 AM
Subject: RE: Hardened Valve Seats
> Did the factory make any changes in the materials used in the head for
> the RBB's? The RBB's that came to the US would never have run leaded
> fuel, and if the materials are the same, and lack of lead was
> a problem,
> we'd have seen it by now.
The federal spec. heads for unleaded use had induction hardened seats that
required a higher concentration of tin in the casting alloy. BL decided to
go this way supposedly after nixing hardened seats. There were a number of
other changes to the engine so it would survive with the catalytic converter
such as going back to smaller valves which allowed larger cooling passages.
Rings were changed to reduce the amount of oil being burnt, and the head
gaskets were upgraded. This info from the "BMC and Leyland B-series Engine
Data" book by Lindsay Porter. According to the reference, hardening the
valve seats alone cost 173,000 pounds.
Kelvin.
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