Yeah, that's what I just discovered searching the archives. Seems the main
opinions are:
CAST IRON HEADS
Opinion #1: No seats. They were just ground into the head. Once worn beyond
spec, a machine shop should be able to put in hardened steel inserts.
Opinion #2: Hardened steel, so no need to worry about lead. Run the lowest
octane that does not knock or ping.
ALUMINUM HEADS
Opinion #1: Bronze valve seats, which will deteriorate without lead. Replace
'em with hardeded steel at your next valve job.
Opinion #2: Hardened steel, so no need to worry about lead. Run the lowest
octane that does not knock or ping.
I also found a post on 311s.org from Steve responding to the same question
(hope you don't mind, Steve):
[quote]
There has been a long on going debate as to the damage of running unleaded
gas in soft seated valves versus using leaded additives. I have read some
interesting thoughts on this and to sum it up. Unless your engine runs at
extreme RPMs and extreme temperatures all of the time there is virtually no
noticeable affect on soft valve seats. An example of an engine that could be
harmed by soft valve seats and unleaded gas would be a that of a dragster. I
know they usually use alternate fuels such as alchohol. This is a radical
example as I am sure they do not use soft valve seats in those motors and
they tend to self destruct more often than not but I think you get my point.
If you still do not feel comfortable running unleaded in the Roadster the
next time you have a valve job done on the head have them put hardened valve
seats in. I have run my roadsters with unleaded Premium Chevron with the
Techron additive already in it. Techron is a cleaning agent. I have not
experienced a valve seat failure to date. --And I drive the snot out of my
cars.
[/quote]
Are we having fun yet?
` ___ '
Pete - (O o) -
----------------------ooO--(_)--Ooo---------
Lake Forest Park, WA
1966 1600 (SPL311-00799)
-----Original Message-----
From: owner-datsun-roadsters@autox.team.net
[mailto:owner-datsun-roadsters@autox.team.net] On Behalf Of Robert Keen
Sent: Monday, July 11, 2005 5:26 PM
To: datsun-roadsters@autox.team.net
Subject: RE: Regular gas...
The regular/leaded/additive topic surfaces with some regularity on the list.
Which is OK.
[snip]
Does anybody know of definitive, impartial tests involving valve seats on
old engines and recent types of gasoline?
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