re. 10v.... interference engine?

[ben swann]

The MC-1 AFAIK can be consideredto be a dynamically interence engine.
Valves won't necessarily interfere at lower RPM, but may at higher
RPM.  When the valves are in motion, they can possibly interfere, due
to the momentum of the valve staying open longer with respect to the
piston, as with the springs, it is not a solid structure.  I hope I am
saying this correctly.  Perhaps someone can explain it better.

When I did my major rebuild/upgrades, I noted that with the stock MC-1
cam I could turn the cam, or motor over independant of timing belt when
replacing the belt.  When I installed the higher lift, higher duration
cam, I could no longer do that.  The motor would lock up if it tried to
turn it even 40 deg. rotation.  I had now made the engine static
interfering as well.

[In going back thru the archives I was convinced that my 10v ('85 4kq
& '88 80q) were non interference engines ... ie. you break the timing
belt and nothing else is broken.  The 20 valve is a different ($) story.
Now I see in the  Marketplace some guy is selling his '90 200tq 10v
with a broken top end because of a timing belt slip. Either:
a. He has a 20v and doesn't know it.
b. Something else caused the damage
c. He doesn't know what he is talking about or
d.  I don't know what I am talking about

Which is it?

Jim]