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Help! Dealer woes . . .
Audi 5-cylinder engines *DEFINITELY* crash the pistons into the valves when
the timing belt breaks while the engine is running. Even the low-compression
turbo pistons with the big "dishes" will hit the valves. I'm 99.99% sure
about this as I have an 83' ur-Quattro engine I purchsed at a very low
price 'cause the timing belt broke and bent *ALL* 10 valves.....
This engine had ~73,000 miles on it. The head had just been rebuilt and
polished/ported and was being run in a PRO-RALLY ur-Quattro when the
belt broke..... :( ($$$)
Interesting...my mechanic says the UrQ's definitely will *NOT* suffer
any damage from broken timing belt - he's done a couple that way (and
he really knows the UrQ's internals). Since that's one of the few
things that hasn't gone wrong with mine so far, I can't say from per-
sonal experience . . . but give me a while . . .
Given the dish in those pistons (makes a good breakfast-cereal bowl! I've
got three nice -- and two not-so-nice -- ones on my table), it's hard to
see how anything could hit them!
Maybe yours had a high-lift cam? Weak valve springs? Was spinning at
9800rpm and floating the valves down into the pistons? Was otherwise
running non-stock clearance -- higher-compression pistons, shaved head
or block, etc.?
I just don't see anyway that all ten valves can get bent - he must have
really been wailing at the time!
As a "general" rule of thumb, I suspect anything over 9:1 compression
will virtually-by-definition smash up valves if it loses the timing