Hallo, here we go again.
More speculative and IMO's .Once and for all, the unleaded question is
not a theory about probables.
At any road speed, the eternal commotion engine must do specific thing
to remain running
FACT #1. Intake / exhaust valves ALL rotate slowly (Yes, even if the
collets dont butt)at about 7 to 10
rpm at moderate speeds 1500 to 4500rpm.
FACT#2. As a valve is placed on its seat by the closing ramp of the
cam, it skids,abeit very little.This keeps the interface between face
and seat clean promoting heat transfere and sealing.
FACT#3. Because many heads are Cast-Iron,there is no inherent strength
in the material to prevent valve ressetion.I have seen many engines
that even with hydrolic lifters wont run due to the valve not fully
closing having taken up all the clearence. Upwards of 0.450
inch.pocketed into the head.(AT first glance
it looked like the valve seat was missing.)
FACT#4 ALL poppet style valve seats must have hard steel inserts to be
at all durable.
FACT#5 The "lead" was a detonation supresant as well as a lubricant.
FACT#6 DK is not allways right.
R. John Lye wrote:
>
> At 06:55 AM 11/19/99 -0800, jim williams wrote:
> > I've talked to several machine shops about unleaded
> >use. I have been told as the rpm approaches 3000 or if
> >the engine is under heavy load there will be seat
> >problems. ^^^^
>
> I would suggest changing that to *may* be seat problems.
>
> Cheers,
>
> John Lye
>
> '59 TR-3A, '62 TR-4, '70 GT-6+
> email: rjl6n@virginia.edu
> homepage: http://avery.med.virginia.edu/~rjl6n/homepage.htm
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