couple of generic engine questions

[drew at scirocco.cs.uoguelph.ca (Drew)]

On Thu, 2004-07-29 at 15:31, Dan Bubb wrote:
> Oh! This will be fun!
> Throwing a rod is when the rod either becomes disconnected from the crankshaft or the piston or the
> connecting rod itself breaks.
> Usually, it becomes disconnected from the crankshaft via the rod bolts or bearing cap breaking.
> I only say this since the post mortem pictures generally show the piston and remainder of the rod
> still attached.
> 
> Two reasons for failure (I can hear Larry chiming in his .02 as I type!):


And a third reason: in an interference motor with a slipped timing belt
or a chewed crank keyway, the rod gets fed up with the stress bestowed
upon it by the piston smacking into the valvetrain, and breaks in the
middle.  The end that's still attached to the crankshaft then punches a
hole in the side of the block (which is surprisingly thin!) - what I
like to call the crankcase ventilation mod.

I picked up a 94 Golf with 1.9 TD (which is perhaps more notorious than
the 9A for having timing gear bolt/crank keyway problems) for cheap
expecting to find some bent valves and smashed lifters.  I was more than
a little surprised to find a small piece of cast sitting on one of the
control arms that looked suspiciously like engine block.  Even more
surprising was that it matched up perfectly to the hole punched out by
the lower half of the number four connecting rod.

I'll take some pictures once I (finally!) get the engine out and apart.

Drew

-- 
 
84 Wolfsburg Ed. Scirocco GTD     http://scirocco.cs.uoguelph.ca/gtd
89 Audi 200 Turbo Quattro Avant
94 A3 Golf GL TurboDiesel, 99 A3 Jetta GL TDI
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