Timing Belt off a tooth ??

[Eric Pipas]

Thanks for the post. I am 99% sure I did it by the "numbers" so to speak.
IMHO that 90 degree axial rotation test is totally worthless measurement. As
an engineer that works in the Aerospace industry, it was just completely
unacceptable.

Now let me get on my soap box about putting timing belts on interference
engines in the first place !!!!
If you are going to design an interference engine, put a freaking internally
lubricated Timing Chain on the thing. As anal retentive as the Germans can
be (I am one so I think I can say) what part of "It's a fundamentally bad
idea to use a glorified rubber band as a timing device" did they not
understand.............Sheezz !!!!



Eric,
I struggled with same concern as well when i did my t-belt but as far as I
can tell the timing is ok.  If both the valve cover & flywheel timing marks
line up properly as you rotate the engine in one direction i think you have
it correct.  Don't jiggy the crank back and forth while worrying about the
'slop' as i did :)

Others will explain it better, but shifting the timing by a tooth will
affect the location of the power band as you rev.  You are basically
advancing/retarding the cam (valve) timing relative to the piston movement.
I think if you're way off you'd have a choppy idle, or if you advance you'll
get more torque earlier.  dunno the exact details here.

>Also the man said to tighten the belt so it could be rotated (Axially) 1/2
>turn. My problem with that is Arnold Schwarzenager and Pe-Wee Herman would

Yeah, 90 degree rotation...thanks alot.  I think germans have calibrated
thumbs.

The concern is that a too tight belt will ruin the water pump bearing
prematurely and thus cause mischief (worst case would be seized pump i
suppose)  With that in mind, i tightened the belt so it would go _just_ a
little past 90 degrees, this turned out to be the same spot the wp had been
in before the tb change.

Search the archives and i think you'll find more advice on the proper belt
tightness.

best of luck,
George Siambis
'88 90q