By left-side do you mean passenger's side or driver's side? I would
expect the passenger side to be off 3-4 teeth, but not the diver's
side. Because of the way the belt wraps around the two pulleys, it
engages far fewer teeth on the passenger side pulley than it does on
the driver side pulley making it more prone to skip. As to why, you
didn't let the engine rotate backwards at any point did you by letting
the car rock backwards down a hill in one of the forward gears did
you? Rule of thumb with these engines: When parking on an incline in
gear, leave it in reverse if the nose is pointing uphill, leave it
first if the nose is pointing downhill. This is so that if the car
creeps or jumps a bit when you release the handbrake, the engine will
be turned in the proper rotational direction when driven by the back
wheels through the gearbox.
There is no reason why you cannot address the broken rockers with the
head on the engine, but you likely have greater problems than that.
Most likely (and it COULD be something else), your loss of compression
is due to a bent valve and that WILL require the head to come off to
address. You might have other bent valves on that side as well. What
likely broke your rockers was the pistons slamming into the open
exhaust valves with enough force to break the rockers. This could also
mean that the pistons have dimples in them from that contact. Those
dimples can cause uneven heating of the piston tops at worst (possibly
resulting in a burned through piston at the hot-spot at some point)
and a build-up carbon in those dimples at best. The upshot of all of
this idle speculation on my part is that you really NEED to remove the
head and have a peak.
George Graves
'86 GTV-6 3.0 'S'
On Feb 13, 2010, at 1:55 PM, Joe Elliott wrote:
The verdict (short version): All three rocker arms in the left
cylinder head are broken, and cylinder #4 exhibits reduced
compression.
Can the rocker shaft be removed with the engine in the car? As
reluctant as I am to spent any money on this dangerously rusty,
essentially worthless car, I'd be inclined to replace the broken
rockers and live with the compromised compression if I could fix it
with the engine in the car.
I'm still puzzled as to why this happened. I couldn't find anything
noticeably wrong with the belt or the tensioner. The ignition was
still timed correctly, the right cam was retarded one tooth, and the
left cam was retarded three or four teeth. What the hell?
Joe Elliott
'82 GTV-6
'88 Porsche 928
'68 Fiat Dino Coupe
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