[net.auto] Subaru Engine Noise

nrv@ulysses.UUCP (N. Richard Venditto) (11/30/84)

I have had the unfortunate experience of buying a used car from a relative.
This is a digression however.  The issue at hand is more tangible.  Does
anyone out there have any experience with Subaru engine problems?  In
particular, my 1979 1600 engine makes a strange knocking sound when idling,
similar to a rod bearing knock, though it is very quiet until it warms up.
Above an idle the noise fades away, and the noise goes away completely when I
disconnect the spark plug to cylinder number 3.

This was last week.  I have since dismantled the engine.  Although the main
bearings were very worn, there was nothing to indicate that number 3 cylinder
would be any noisier than any of the other cylinders.  The connecting rod
bearings were all about the same, not really worn enough to make noises.
The cylinders had little or no wear.  The engine has 55,000 miles of easy
driving but infrequent oil changing (evidenced by much sludge and varnish
inside).  I would be overjoyed to find an explanation for the problem, since
I have reassembled the engine with all new bearings only to find the noise is
still there.  (The crankshaft was measured by a machine shop and found to be
quite all right.)  Any ideas?  Is it something peculiar to the design of the
engine (it is sort of a water cooled version of the old vw beetle engine)?

I learned one thing already from this that I can share with any of similar
fate.  I rushed through the rebuild, since I needed the car to get to work.
I saw the worn main bearings and replaced them with my fingers crossed.
Crossing your fingers doesn't seem adequate protection against having to do
the job again.

		Rich Venditto (ulysses!nrv @ Bell Labs in Murray Hill)

prg@mgweed.UUCP (Phil Gunsul) (12/01/84)

[ knock knock...  who's there??]

Just a guess would be that the intake valve could be sticking.  When
the plug is connected and the cylinder fires, the valve is forced
closed.  A second guess would be that you have a hair-line crack
in the distributor cap and it is cross-firing with another cylinder.

What do I win if I was right??  :-)  :-)  :-)

Phil Gunsul  --  AT&T CP