Vortec Engine
Question:
Hi everybody…can any body tell me something about a v8 GMC engine? My question, what is a vortec?. Tnx in advance. Frank
Response:
Here’s the basics as I’ve come to know them…. Since the term Vortec is, I believe, only used in Chevy Trucks (and their GMC twins), then I’ll presume you want info about the truck motors. Vortec is a modification to the standard motors that added a freer-flowing intake and direct fuel direction. It boosts power while making it easier for the motor to meet emission regs. Currently, Chevy is offering a 4.8L, 5.3L and 6.0L V-8 in their new ‘99 Silverado pick-ups (also a 4.3L V-6, but we’re discussing -8’s here). These motors use deep skirt blocks, cross-bolted main bearing caps, sequential electronic fuel injection, and a special ignition system which instead of having one coil which feeds a distributor which in turn fires 8 plugs, it has no distributor and one coil *per cylinder*, which make it more durable (no moving parts) and increases power. These are single camshaft motors with hydraulic lifters and pushrods, and are based on the same design as the LT-1 Corvette motor (now available in Camaros and Firebirds). In ‘96 thru ‘98, Chevy offered a 5.0L and 5.7L (350 cubic inches – my favorite) V-8 with the Vortec improvements. The 5.0L and 5.7L were essentially the same motor with different cylinder dimensions, and the 5.7L is one of the most wildly sucessful motors ever produced, with a heritage that goes back 50 or more years. These motors also had single cams with pushrods and lifters. Much has been made of overhead cams, etc., but these motors worked great as is. I always wanted one of the 5.7L Vortec motors, but ended up getting a diesel instead. In ‘88 thru ‘95, Chevy offered the same 5.0L and 5.7L V-8’s, but the Vortec improvements were only available in the 4.3L V-6. The bottom end is exactly the same all the way thru ‘98. Fuel injection was provided via low-pressure throttle body (which looked all the world like a carburator from the outside, but wasn’t). I owned an ‘88 5.7L V-8 in a Chevy C1500 P/U and that truck ran beautifully until I traded it in back in ‘97 (not because of the motor, but rather I needed an extended cab. I still miss that truck.) For comparison, here are some numbers: ‘88-’95 5.7L V-8 210hp/300 ft-lbs torque ‘96-’98 5.0L V-8 230hp/285 ft-lbs torque ‘96-’98 5.7L V-8 255hp/330 ft-lbs torque ‘99 4.8L V-8 255hp/285 ft-lbs torque ‘99 5.3L V-8 270hp/315 ft-lbs torque ‘99 6.0L V-8 300hp/355 ft-lbs torque Hope this helps – Jonathan — Acta Non Verba – Deeds Not Words Jonathan Race, Firefighter/Paramedic II Orange County (FL) Fire-Rescue Division A-Shift, Station 41 – "The Shark Tank" (http://home.mpinet.net/backdraft) Reply to: jrace at bitstorm dot net
