V-6 Timing Belt Burning Smell

[Dio Genio <diogenio@xxxxxxxxx>]

Thanks to all who gave suggestions.  Here is an
update:  My tachometer is dead on accurate, so I'm not
hitting the rev limiter. I checked the cam belt
tensioner for free rotation and the back side of the
belt for signs of wear, or rubbing. Both OK. Started
up the engine and watched the tensioner to see if it
was seizing up at higher RPMs, but there were no
problem signs at all. There was no burning smell at
all coming from the front of the engine when the car
was parked, even after revving it over the 4k point.

Seems this smell occurs only under load. Since the cam
belt is under the same load whether driving or parked,
I'm now beginning to suspect the guibos, as proposed
by one of the Digesters. It is hard to imagine that
these things would get hot enough to smell burnt, but
under their high internal stress, it might be possible
when they are close to failure. An odd thing happened
last night as well...while accelerating to get on the
highway, I heard and felt a momentary "ca-clump,
thunk" under the floor pan.  Thought it might have
been a rock, but now I'm wondering if I lost a chunk
of guibo, as one of the Digesters did after a period
of smelling burning rubber at high rpms...? No
driveline vibrations are present.

Guess I gotta check the guibos now. Per suggestions,
I've ordered a new timing belt and tensioner, the
164-style mechanical one. Although I've read a lot
about how unreliable they are, Centerline Alfa Parts
maintains they are 100% ok, IF they are installed
properly. The only other option is to use a "solid"
tensioner like the Zat unit, but one needs the idler
wheel from an old oil-powered tensioner.  Also, there
is no compensation for engine expansion, so I'm afraid
of setting the thing too tight and snapping a belt
that way, or too loose and jumping some teeth. Either
scenario rather sucks.

Boy, I sure like the old chain driven cams on my
4-cylinder Spider...

DENNIS 
78 Spider
87 Milano Platinum (sans ABS)        
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