From: firstname.lastname@example.org (Dave Williams)
Subject: Chevrolet Vega
Date: 20 Aug 94 08:34:00 GMT
-> When the Chevrolet Vega was introduced (as long ago as that!), it was
-> reported as having an alloy block with no liners and alloy pistons.
-> To get around the obvious friction problems, I think the pistons were
-> Did it work? What happened next? I never heard. This is not a car
-> which was ever sold here.
A Pocket History of the Vega and its Engine: Clip and Save!
The Vega engine was as you described. The block was high-silicon-
content aluminum, with the bores acid-etched to remove the aluminum,
giving a mostly silicon bore. The pistons were either iron or tin
plated depending on what reference you use; Chevy probably
experimented a bit.
The engine only lasted a few years, with a horrible service record.
Chevrolet finally went to iron liners and conventional pistons, and
replaced the oddball taper-screw valve adjusters with hydraulic
followers. Chevy claimed the service problems (scored cylinders, scored
walls) were mostly due to improper maintenance; ie Americans typically
don't *ever* change oil. Most American cars probably hit the junkyard
with the same oil they left the factory with. There's nothing wrong
with the basic materials and manufacturing process - Porsche and
Mercedes, among others, do the exact same thing nowadays.
The block itself was designed in partnership with Lotus, who wanted to
use it as the basis for a cheap racing engine. To the best of my
knowledge Lotus never used the Vega block or anything similar. The
high tech aluminum block had cast iron main caps (really!), a cast iron
crank (normal), and an enormous cast iron cylinder head that weighed
almost as much as the whole short block. Why? Baud alone knows why.
The tall, topheavy, long-stroke Vega motor had some pretty bad vibration
problems, "cured" with huge rubber motor mounts. If you opened the
hood when the engine was idling, it would be rocking and bouncing
around like it was trying to escape. Damnedest thing I ever saw.
Performance-wise, it was about the same as Ford's 2.3 Lima engine.
Chevrolet made the 2300 Vega in one barrel and two barrel versions, and
then the destroked 2000cc Cosworth Vega, double overhead cams, four
valves per cylinder, five speed, fuel injection. They were expensive
and not much faster than the standard Vegas (300cc short, plug smog),
and Chevy only sold a few. There's moderate collector interest, though
prices are still pretty low and don't show any sign of going up soon.
The Vega engine itself was a bastard project. John Z DeLorean (you've
heard of him?) brought it with him from Pontiac to Chevrolet. The
design was only half-finished when handed over to a new group of
engineers who evidently suffered from the "not invented here" syndrome.
DeLorean ordained the new four would do into Chevy's new small car, the
Vega. The Vega was originally to use an Opel engine until the GM Rotary
Engine (Wankel) came online. The Vega body itself had problems -
according to DeLorean himself ("On a Clear Day You Can See General
Motors") the chassis of one of the prototypes collapsed on the proving
grounds. Whoops. Back to the CAD stations...
The Vega limped along on the aluminum block, iron head, OHC four for
several years, then got the Buick 231 V6. The OHC four got iron
sleeves, then was replaced by the 2.5 "Pontiac" OHV four, which was
actually a resurrected version of the old Chevy II four cylinder of the
'60s. The Vega became the Monza, which got the 262, 305, and (for '75
only, California only, automatic trans only) the 350 V8. The GM Rotary
Engine's delivery date kept slipping, first due to reliability problems,
then due to fuel economy problems, and finally GM couldn't make it pass
the smog tests. In 1978 the prototype plant was turned over to GM's
Delco division, which converted the plant to make power seat mechanisms.