[Top] [All Lists]

Unleaded fuel and valves (was: F experiences, for some odd reason)

Subject: Unleaded fuel and valves (was: F experiences, for some odd reason)
From: (Denise Thorpe)
Date: Fri, 26 Jan 96 13:22:13 PST
Todd Byers said:

> In my 1962 MGA the previous owner always ran with premium unleaded
> fuel so I continued the practice with no additives.  I don't know if
> that was the entire problem, but it ate a valve seat once so I
> replaced the head (again with original seats) and fairly promptly
> burned a valve.  Since then I have had hardened bits put in, but in
> retrospect I would have probably sought out leaded fuel.

Valves burn from lean running.  A burnt valve has a really interesting 
curving pie shaped piece cut out of it.  I've always admired the shape 
of the burnt out part of a valve.  I suspect that some simple three-
dimensional equation with echoes in the natural world would describe its 

I can't describe the damage to a valve from using unleaded gas because 
I've never seen any but I've heard that it only causes a slight loss in 
compression.  However, I have seen the damage caused by a hardened valve 
seat that's come loose.  This is not that uncommon with hardened valve 
seats and a loose valve seat will cause _much_ more damage than unleaded 

I've put 150K miles on the perfectly stock head of my '67 B and never had 
any problem using premium unleaded.  Don't worry, be happy.

Denise Thorpe 

<Prev in Thread] Current Thread [Next in Thread>