clanking sound 72 z600 coupe (need engine diagnostic help)

[jeffanson2005]

Well. I was all excited to start my brakes project, but when I was
moving my 600 out then back into the garage, something happened. The
engine briefly made a clanking sound (as if the chain inside came off)
and the car died. Turned it over a few more times to see where the
sound was coming from. Couldnt hear anything. Turns out only one
cylinder was firing. Pulled the non firing cylinder spark plug out
and found the gap electrode and porcelain was bent and damaged
(something inside was hitting it). I can see down the spark plug hole
and see some metal shavings (not much). So something inside broke off
and was probably smashing the spark plug as the piston moved up and
down the last couple of times.
Engine experts... from your experience, what has happened? And what
do you think is the damage and what can I do to repair it. thanks in
advance for any help or comments.
Jeff
Miami, FL
1972 Z600

[mterrens]

I am not one of those "experts" but...
If the timing chain should break or come off, the engine won't be timed right.
If the engine is not timed right, the valves and the pistons can be in the same place at the same time.  Uh oh.

> ----- Original Message -----
> From:
> jeffanson2005
> To:
> anzhonda600owners@yahoogroups.com
> Sent:
> Wednesday, January 03, 2007 4:50
> PM
> Subject:
> [anzhonda600owners] clanking
> sound 72 z600 coupe (need engine diagnostic help)
> Well.  I was all excited to start my brakes project, but
> when I was
> moving my 600 out then back into the garage, something
> happened.  The
> engine briefly made a clanking sound (as if the chain
> inside came off)
> and the car died.  Turned it over a few more times to
> see where the
> sound was coming from.  Couldnt hear anything.
> Turns out only one
> cylinder was firing.  Pulled the non firing
> cylinder spark plug out
> and found the gap electrode and porcelain was bent
> and damaged
> (something inside was hitting it).  I can see down the
> spark plug hole
> and see some metal shavings (not much).  So something
> inside broke off
> and was probably smashing the spark plug as the piston
> moved up and
> down the last couple of times.
> Engine experts...
> from your experience, what has happened? And what
> do you think is the
> damage and what can I do to repair it.  thanks in
> advance for any help
> or comments.
> Jeff
> Miami, FL
> 1972
> Z600

[Tom Ruwart]

Hmmm... I would first make a sacrificial offering to the Engine Gods
(like burning one of those cheap car air fresheners) and hope that
they spare you the cost of an engine overhaul and reboring the
cylinder walls. Sounds like you may have lost the timing chain which
caused a misfire and the resulting bad things happened. But the
damaged gap electrode says that the piston rod may have broken free
from the piston at some point. I suspect that if you can turn the
engine over and watch the piston movement through the spark plug
holes (both of them) you should be able to tell right away if you
have a broken piston rod. Otherwise, me thimks the only other way to
tell is to take the head off and have a look. Mike or Bill should
have some better advice on what might be the problem since they knows
these engines inside-out.

[mterrens]

Also take the cover off the camshaft housing to get a sense of what the status of the chain is.

> ----- Original Message -----
> From:
> Tom Ruwart
> To:
> anzhonda600owners@yahoogroups.com
> Sent:
> Wednesday, January 03, 2007 5:20
> PM
> Subject:
> [anzhonda600owners] Re: clanking
> sound 72 z600 coupe (need engine diagnostic help)
> Hmmm... I would first make a sacrificial offering to the Engine > Gods > (like burning one of those cheap car air fresheners) and hope that
> they spare you the cost of an engine overhaul and reboring the
> cylinder walls. Sounds like you may have lost the timing chain which
> caused a misfire and the resulting bad things happened. But the
> damaged gap electrode says that the piston rod may have broken free
> from the piston at some point. I suspect that if you can turn the
> engine over and watch the piston movement through the spark plug > holes > (both of them) you should be able to tell right away if you > have a broken > piston rod. Otherwise, me thimks the only other way to > tell is to take the > head off and have a look. Mike or Bill should > have some better advice on > what might be the problem since they knows > these engines inside-out.
> --- In
> anzhonda600owners@yahoogroups.com
> ,
> "jeffanson2005"
> wrote:
> > Well.  I was
> all excited to start my brakes project, but when I was
> > moving my 600
> out then back into the garage, something happened.
> The
> engine briefly made a clanking sound (as if the chain inside came
> off)
> > and the car died.  Turned it over a few more times to
> see where the
> > sound was coming from.  Couldnt hear
> anything.  Turns out only one
> > cylinder was firing.  Pulled
> the non firing cylinder spark plug out
> > and found the gap electrode and
> porcelain was bent and damaged
> > (something inside was hitting
> it).  I can see down the spark plug
> hole
> > and see some metal
> shavings (not much).  So something inside broke
> off
> > and was
> probably smashing the spark plug as the piston moved up and > > down the > last couple of times.
> > Engine experts...  from your
> experience, what has happened? And what
> > do you think is the damage and
> what can I do to repair it.  thanks
> in
> > advance for any help
> or comments.
> > Jeff
> > Miami, FL
> > 1972
> Z600

[jeffanson2005]

Whoops! Also, I did open the top of the engine with the 4 10mm bolts
and saw the timing chain in good condition and turns with the
engine. Piston problem may be the cause on the drivers side of the
engine.

[friend]

Hi Jeff;
There are a couple of things you can do.
first, pull both spark plugs, then by hand rotate the engine with a 17 mm wrench on the pulley bolt, turning it forward (move the wrench from back to the front of the car).  until the timing mark on the pulley is on the T mark on the case (top dead center).  With a small flash light look to see if the pistons are both up to the top.  If not rotate it again until the timing mark is again at the T.  check again in the spark plug holes.  Now that they are both at the top, look to see if they are both at the top (one is not lower than the other).
With the cam box cover removed see if the springs are lose on either of the valves ( At top dead center there should be 3K slack between the cam and the rocker arm.)  I think you either dropped an exhaust valve or the piston connecting rod went on the lower end causing the piston to elongate hitting the spark plug.  Either will mean pulling the engine to do the job right.
Bill

> -----Original Message-----
> From:
> anzhonda600owners@yahoogroups.com
> [mailto:anzhonda600owners@yahoogroups.com]
> On Behalf Of
> jeffanson2005
> Sent:
> Wednesday, January 03, 2007 1:50
> PM
> To:
> anzhonda600owners@yahoogroups.com
> Subject:
> [anzhonda600owners] clanking sound 72 z600 coupe (need engine diagnostic > help)
> Well. I was all excited to start my brakes project, but when I > was > moving my 600 out then back into the garage, something happened.
> The
> engine briefly made a clanking sound (as if the chain inside came > off) > and the car died. Turned it over a few more times to see where > the > sound was coming from. Couldnt hear anything. Turns out only > one > cylinder was firing. Pulled the non firing cylinder spark plug > out > and found the gap electrode and porcelain was bent and > damaged > (something inside was hitting it). I can see down the spark plug > hole > and see some metal shavings (not much). So something inside broke > off > and was probably smashing the spark plug as the piston moved up > and > down the last couple of times.
> Engine experts... from your
> experience, what has happened? And what
> do you think is the damage and what
> can I do to repair it. thanks in
> advance for any help or
> comments.
> Jeff
> Miami, FL
> 1972 Z600