I've had
>hardnened seats for a few years now...and the iron guides that the guy
>"knurled" had eaten up my valve stems and seals. Mike what clearance did you
>have on those bronze guides?
>My machinest said 2 thou minimun, more like 2.5/3.0.....Skip Kelsey been
>running bronze guides for years and highly recommends them. Hardnened seats
>can fall out if not properly installed.....problems can occur in all parts of
>an engine if not properly done!!
>
>My opinion is that fancy stuff for unleaded gas is not needed until you have
>to pull the head for other reasons, then why not do it, it doesn't cost
>much....The brits are paranoid on this subject with out a lot of
>reason....however given their driving habits, constant high engine speed to
>beat out every yank in a roundabout my give them pause. Over here where you
>guys don't put a 1000 miles a year on your garage queen, why worry! ;-)
>
Terry, I didn't want to worry you. Obviously, my guides were reamed just a
hair too little, as my problem was very occasional. I agree that no one
should redo the head unless something demands a rebuild anyway
The point is the guides themselves. Here in the northeast, it isn't
realistic.to drive during the winter and the pro who looked at my head said
that this inactivity allows the bronze guides to oxidize. He claims to have
taken heads apart and found powder from the guides messing up everything.
As to the seats, he feels that the modern engines with castings made for
the new seats are better prepared for them , taking a 50 year old head and
installing them, no matter how good the machine shop , will always be a risk.
The real issue is whether the risk of something going wrong outweighs the
need for it in the first place. My TF is not a garage Queen, its been coast
to coast, all over Canada, and Great Britain. But I do not race it, drive
around town most of the time (thats why I have kept the standard rear) and
is really only runs hard when going to a gathering. Last year we went to
Indy and drove 650 miles in one day on interstates in near 100 degree
weather. At a steady 4000 rpm , its hard on the engine. Does that type of
driving once or twice a year require a no lead head. I don't know.
You are right, the British are nuts on the subject. I am a little less
paranoid about the effects of unleaded., yet I am not convinced one way or
the other. I feel the same way about additives such as "Relead"
Good luck with the TA at the gathering
Mike.
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