Paul.....In our fairly considerable experience (working on LBCs since the
mid-Seventies, coping with unleaded fuel since about 1978), exhaust valve
seat recession and subsequent burning of valves is a definite problem if the
head has not been fitted with hardened exhaust valve seats. This seems to
particularly affect those cars that are driven for long periods at steady
speeds. Short trips in traffic don't seem to result in the problem becoming
apparent for much longer - but it will eventually manifest itself.
I keep reading how English motoring enthusiasts are in a state of virtual
panic at the onset of the introduction of unleaded fuel. Fear not, it really
isn't that much of a problem - or, should I say, the cure isn't. Simply
remove cylinder head when the first sign of a burnt valve appears (low
compression on one or more cylinders), have a competent machinist do a valve
job and install a set of hard seats for the exhaust valves. This latter
procedure adds about $50 to the cost of the job over here, a small price to
pay for peace of mind!
Lawrie
British Sportscar Center
-----Original Message-----
From: Paul Hunt <paul.hunt1@virgin.net>
To: mgs@autox.team.net <mgs@autox.team.net>
Date: Monday, June 08, 1998 10:54 AM
Subject: Valve Seat Recession
>What are the current opinions regarding valve seat recession when using
>unleaded fuel with a head with non-hardened seats? No ression? Some
>recession? If the latter, under what conditions?
>
>Thanks,
>PaulH.
>
>
|