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View Full Version : GM's 3.9L V6 (that isn't a 3.9L)


Bass-o-Matic
02-05-2005, 08:54 AM
This isn't really NEWS, other than I haven't read anybody else (in the press or elsewhere) mention this. I find it intriguing, nonetheless (or all-the-more?)<p>The new 60-degree 3.9L V6 in the Impala (and going into the G6, apparently) isn't actually 3.9-liters in total displacement. It's actually 3,791cc... which begs the question, "Where did the '3.9L' designation come from?".<p>I think GM's feeling kind of sensitive to the criticisms in the past (hell, on the Pontiac side, that would be right now) of offering old-tech powertrains. In particular, how many more times would GM slap an admittedly old, proven but woefully behind the times Buick 3.8L V6 in an otherwise new car? <p>I think they decided that they had to designate it something other than 3.8L, if only to avoid the possible assumptions that it was the "old" engine.<p>By the way, one of my favorite GM cars from the '80s (if only to drive) was the GNX, so please don't assume that I'm either auto-anti-GM or -Buick or -3.8L V6...

taskbearer
02-05-2005, 09:10 AM
thatys a little odd, if not overtly bizzare. At least they can claim the engine has variable valve timing.

Bass-o-Matic
02-05-2005, 10:18 AM
Isn't it? <IMG NAME="icon" SRC="http://images.zeroforum.com/smile/emwink.gif" BORDER="0"> I thought so when I was looking at specs.<p>I don't have insider info at GM, as to why they did it; Just my best guess as to why you'd call it a 3.9L.<p>Arguably, in this segment dominated by relatively small, high output (in other words, high specific output) engines from Japanese makes, I would think there'd be some concern about aiding the perception that a company like GM has to go to "almost 4.0L" of displacement to compete with the Japanese. I know that 3,791cc is still a big engine, but it's at least in the ballpark, if you consider the Mitsubishi and Hyundai engines. 3.9L just sounds like a displacement from the '60s, for those of us who can remember. I'd have rather called it a "3.7L" (although I think that's the Chrysler Slant Six displacement).

taskbearer
02-06-2005, 11:06 PM
GM is still strugling to cut costs by avoiding new technologies yet their profits are less than mediocre compaired to the tech savy japanese carmakers. The most resounding praise GM can get regarding pushrods is the new LS7 engine, at leat in the Z06 it aceives performance close to Mercedes SLR for a price lower than a viper.

Bass-o-Matic
02-07-2005, 08:00 AM
Agreed<p>I'm not actually against OHV as a matter of principle, especially as we've seen GM evolve it, in production (on Corvette, in particular) and in concept (check out the XV8 engine that was in the original Opel Signum show car).<p><A HREF="http://www.gminsidenews.com/xv82.htm" TARGET="_blank">http://www.gminsidenews.com/xv82.htm</A><br><A HREF="http://www.acarplace.com/brands/gm/xv8-engine.html" TARGET="_blank">http://www.acarplace.com/brands/gm/xv8-engine.html</A><br><A HREF="http://www.orbeng.com.au/orbital/directinjection/csgm.htm" TARGET="_blank">http://www.orbeng.com.au/orbit...m.htm</A><p>Pretty amazing engine, if only it were to come true. This takes the inherent advantages of pushrod engines (lightweight, compact, relatively-simple) and takes them to the level of technical sophistication that the OHC/DOHC engines all purport to offering.

Naga Royal Guard
02-07-2005, 10:46 AM
pushrod engines can have a large displacement but remain TINY, its almost scary

Nick
02-07-2005, 12:51 PM
thats one of the many beauties of pushrods...the fact that not only do they offer a lrger displacement than DOHC's but in smaller spaces....DOHC's with the displacement of pushrods are freaking huge ass engines...

taskbearer
02-07-2005, 06:02 PM
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>CarpFan</b> &raquo;</i></TD></TR><TR><TD CLASS="quote">Agreed<p>I'm not actually against OHV as a matter of principle, especially as we've seen GM evolve it, in production (on Corvette, in particular) and in concept (check out the XV8 engine that was in the original Opel Signum show car).<p><A HREF="http://www.gminsidenews.com/xv82.htm" TARGET="_blank">http://www.gminsidenews.com/xv82.htm</A><br><A HREF="http://www.acarplace.com/brands/gm/xv8-engine.html" TARGET="_blank">http://www.acarplace.com/brands/gm/xv8-engine.html</A><br><A HREF="http://www.orbeng.com.au/orbital/directinjection/csgm.htm" TARGET="_blank">http://www.orbeng.com.au/orbit...m.htm</A><p>Pretty amazing engine, if only it were to come true. This takes the inherent advantages of pushrod engines (lightweight, compact, relatively-simple) and takes them to the level of technical sophistication that the OHC/DOHC engines all purport to offering.</TD></TR></TABLE> <p><br>My goodness, This is the first time I've heard of a pushrod with two camshafts. thought of it before but, never seriously. It makes me wonder why GM is showing no sign of making this a reality. I mean they can replace their current pushrod range with that, considering the 75 degree angle can serve as a V6, V8, V10, V12. the specs match those of OHC and the costs could be significantly lower.

Ghost_In_The_Machine
02-07-2005, 06:43 PM
The 18 Valve 3.9 is supposed to make 270 HP<br>No Firm Announcements of production though<p>The Gm Technology page on the OHV 3 Valve per cylinder<p><A HREF="http://www.gm.com/automotive/gmpowertrain/tech/pdf/OHV_3valve.pdf" TARGET="_blank">http://www.gm.com/automotive/g...e.pdf</A><p><br>

CalinG7
02-08-2005, 11:54 AM
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>CarpFan</b> &raquo;</i></TD></TR><TR><TD CLASS="quote"><br><A HREF="http://www.gminsidenews.com/xv82.htm" TARGET="_blank">http://www.gminsidenews.com/xv82.htm</A><br><A HREF="http://www.acarplace.com/brands/gm/xv8-engine.html" TARGET="_blank">http://www.acarplace.com/brands/gm/xv8-engine.html</A><br><A HREF="http://www.orbeng.com.au/orbital/directinjection/csgm.htm" TARGET="_blank">http://www.orbeng.com.au/orbit...m.htm</A><br></TD></TR></TABLE><p>Those engines sound fantastic, a great combination of technology and low cost. Why haven't we seen these come out yet? Or when will we? Are they geing applied to the current engine lines?

taskbearer
02-09-2005, 07:03 AM
long live the PUSHROD engine....................funny and GM is thinking of bringing extra expensive fuel cell to market first.

Smithie
02-13-2005, 01:26 PM
I think it should be illegal (if it already isn't). It's no different than Pepsi actually taking out some advertising space to say their cans now contain 360ml, when in fact they still have 355ml. How low will this company go?! There seems no end to what they'll do to sell cheap cars to misinformed consumers.