I agree with Rob, in that the effect of unleaded fuel on
older engines is not a real serious threat. I would
certainly not go to the trouble and expense of
installing hardened exhaust seats on an engine that
isn't already apart for a valve job or rebuild.
Particularly in a mildly tuned, low compression stock
engine, where the valves don't really get hammered with
violent cam action and stiff spring pressures, at high
RPM's.
My feeling is that lead additives are probably not
necessary for most of these applications, and represent
an unneeded expense, unless we are talking about a
street Hemi or some other vintage musclecar mill.
My 228 GMC six did not have hardened seats, and I never
ran it with any additives. I probably put 15 thousand
miles on it, the majority at highway speed, using only
unleaded - and on teardown after it blew a head gasket,
I noticed no appreciable valve seat recession. Total
mileage on the engine was about 60K at that point. Of
course, I had hardened seats installed as part of the
ensuing valve job. I have seen a couple of 235 heads,
and several vintage Brit motorcycle engines, in similar
condition.
As always, your results may vary, but this has been my
experience.
Jack / Winter Park FL
> First off, unless I am mistaken, leaded gasoline was still pretty readily
> available 20 years ago, so can think of no reason hardened seats would have
> been installed at that time in the rebuild. The only way to tell if you
> have hardened seats though, is to pull the head. If you are planning to
> keep the 216 (maybe now is a good time to think about swapping in a 235 or
> other?), I am not sure if the missing lead is as critical as you might
> believe. The only reason I had hardened valves put in when I rebuilt my
> 235, was because I knew it would be undergoing a cross-country trip as soon
> as it was completed. I have heard from MANY knowledgeable people, that
> unless you do a lot of long distance driving, the hardened seats are really
> not necessary, nor is the additive. I have started using the additive only
> when I know I will be driving long distances (on my '67 and '70 Skylarks).
> Anyway, if you either DO do a lot of long distance driving with the 216, or
> it simply gives you comfort to feel that you are doing everything possible
> to preserve your engine, then the answer to your last question is "no", the
> lead additive will NOT hurt your engine, so add it as you see fit. It WILL
> help it, but simply may be an unnecessary expense.
>
> Rob
> ----- Original Message -----
> From: Brad Newman <bkn@cyberramp.net>
> To: oletrucks <oletrucks@autox.team.net>
> Sent: Friday, June 04, 1999 5:59 AM
> Subject: [oletrucks] lead additives
>
>
> > All the talk about leaded vs unleaded fuels and hardened valve seats and
> > such got me wondering. My 40 1/2 ton has the original 216, but as I am
> > at least the 3rd owner, I have no idea (and neither does the guy that I
> > got it from) if the engine has ever been rebuilt, and if it has, if the
> > newer "hardened" valve seats were installed.
> > Is there any way to tell if this has been done? The truck was restored
> > around 20 years ago...........if the 216 was rebuilt at that time, would
> > it have been commonplace then to add hardened valve seats? Also, if I go
> > ahead and start adding a lead additive, will it hurt the engine if I do
> > have hardened valve seats?
> > Thanks for the help
> > Brad
> >
> > oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
> >
>
> oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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