[Shotimes] Is engine OK? was: SHO cranking but not starting

[Koper Jim]

Steve,

92 MTX.

It thought it might be too much slack (especially at the top like that), but
the belt was replaced summer of '02, about 10-12K miles ago along with the
water pump, crank position sensor, cam position sensor, shims, plugs, wires.
I wonder if the belt tensioner has come loose. Probably can't adjust it
through the little window on the middle(?) cover. I'd bet that I have to
tear apart the front of the engine to really adjust it.

A belt jumping a tooth is a somewhat rare occurrence?  Have you noticed that
there are, IIRC, TWO 'white' marks and one 'yellow' mark on the crank
dampener?  Which white mark do you actually use? Helms does not specify, and
perhaps that is where the problem started. I had a good amount of guidance
(by phone and e-mail!) with George Fourchy that summer, so I figured I did
it correctly. Maybe not! Perhaps the slack started IF I used the wrong white
mark....

I didn't pull the cover completely off--just enough to see if the belt was
still rotating or if it had broken.

Dampener pulley was loctited and torque to 115 lb-ft, per Helms. I wondered
if I should have added a little more to that number. What torque spec have
you used?

Thanks for your contributions!

Jim



<your message below>

Several issues come to mind.

Too much timing belt slack.  How old is it?  ATX or MTX?  Might just be a
stretched belt that has jumped time - check static belt alignment.  If ATX,
might be the tensioner has lost pressure.

The noise is likely to be either rod bearings, cam chains/tensioner, or
crank cancer.  Was there a good dusting of reddish powder inside the timing
belt covers?  This is a strong (but not the only) indicator of crank cancer.
A mechanic's stethoscope is a valuable tool for isolating the source of the
knock/noise.  About $10 Unless you have a harbor Freight nearby, then $2.50
on one of their sales).

Do check the IAB.  It is likely the source of your idle problems.  Look for
other vacuum leaks before jumping into replacing it.

Steve