: I just bought a 64 valiant with /6 225. It is
: the first older car that i've had and I'm
: concerned about running unleaded gas in the
: engine. What (if anything) do i need to do
: to convert the engine? or should i just plan
: on using additive? any help is greatly
: appreciated

: '72-'76 heads came from the factory with
: induction hardened valve seats or you can
: have your machinist install hardened seat
: inserts when you get your next valve job.
: I've been driving a '66 Valiant for several
: years with no problems...but I don't get on
: it or run it hard much. I also haven't had
: the head off to look for recession---all I
: know is it's still running great and has
: good compression. I've heard a variety of
: opinions about how much of an issue this
: really is...maybe Doc will jump in and give
: us his view on this. He'll be the one who
: knows.

: I just bought a 64 valiant with /6 225. It is
: the first older car that i've had and I'm
: concerned about running unleaded gas in the
: engine. What (if anything) do i need to do
: to convert the engine? or should i just plan
: on using additive? any help is greatly
: appreciated

:
: Red did a good job covering the options, I
: agree that it is an issue to deal with when
: (if) the head comes off.
:
: The big tip-off for everyone running the early
: (pre 70) engines / heads is the valve lash
: adjustment, check the lash adjustment at
: least once a year, if the exhaust valves are
: getting tighter over use (less then .020
: hot) then the valve seat(s) are receeding
: and it is just a matter of time before you
: will have to do valve seat work. (my 66
: wagon is doing this, I've loosened the
: exhaust valves 2 times now, it has a factory
: induction harden "later" head but
: it is not enough protection for all the race
: car towing I do)
:
: For an early car which is running well, I would
: adjust the valve lash (to get a base line)
: and use additive, especially if you are
: taking a long trip on the freeway. You do
: not have to use the stuff in every tankfull
: and just a little goes a long way. (split a
: can between a couple of fuel loads)
: One interesting thing I noticed is that the old
: original engines which were run many years
: on leaded fuel seem to be more resistant to
: recession, I can only guess that somehow the
: lead gets into the seat surface and stays
: there a while. (note that there is leaded
: race fuel avaiable for "off road use
: only") ; - )
: DD

: Definitely use the anti wear additives. I
: don't know if any one brand is better than
: another, read the ingredients they're
: probably mostly the same. Here's my bit of
: non-clinical anecdotal evidence. I put an
: old style head on an Al slant 6 (newer
: styles don't fit) and used additve. I put
: about 35000 on the engine before I had to
: disassemble due to cracked block. There was
: no abnormal wear on the valve seats.
: Regarding late model cylinder heads, post '74,
: the induction hardening on these heads is
: very thin! They will not take a valve job.
: Some may disagree as to thickness, and I
: have heard that the hardened depth got
: thicker in later years, but the process
: itself is designed to give a hard SURFACE.
: Once that surface is ground away by a valve
: job, you now have soft cast iron and will
: need to install hardened seats.
: I leaned this the hard way when a Mopar
: Performance tech swore on all that was holy
: that a set of 360 heads would take one valve
: job.
: I did, didn't use additive, and after about
: 60k, when the power drop became too
: noticable to ignore (ie got beat by a
: Mustang GT), found that the exhausts had
: beaten themselves .100" into the head.
: Others may have stories of happier results, but
: I wouldn't bet my expensive engine on it.
:
: Bob Troy
: Santa Monica, CA

:
: I believe this topic surfaced on the
: forwardlook.net discussion board (55-61
: Chysler made vehicles) and the point made
: there was that engines that had many hours
: of operation running leaded fuel actually
: had lead imbedded valve seats. Therefore,
: due to this residual effect, they could run
: very safely on unleaded for an extended
: period of time. What's extended? Who knows .
: . . that's why I'd echo what's been said
: before. Drive away but keep track of exhaust
: valve lash changes.

:
: I have heard this as well, that the induction
: hardening is less than 0.010" thick,
: and so will likely be removed on a valve
: job.
:
: Lou