Blame it on Buick

Please help me clear up a few things/myths/misconceptions/etc. that I have in my head.

Ive heard (and read) that Buick has had a lot of influence in the design of modern Chevy/Corporate GM engines. For instance, the fast-burn type compression chamber that Buick built into the 455 didnt have a fancy name back then, but was what Chevy starting using in the '90s, calling it Vortec. Is this true?

Ive also heard that the bottom end of the LS series engines has a lot more in common with Buicks 231/3.8 series V6 than the original Chevy small block. If so, what, exactly is it that is so similar?

What gives the 455 such good torque output in the lower RPMs and why does it rev so well when other high revving V8s dont make power down low (or visa-versa)? Is it something to do with the relatively short stroke and intake runners?

Also, what other designs or ideas can be credited to Buick? I know Buick had a REALLY good R&D department in the 50s and 60s. I also know they were involved in the turbo-hydramatic developments and maybe the quadrajet. Anything else?

My technical understanding of engines is pretty limited, as you can see. I was just wondering about this stuff.

 

:gp:
Subscribed in anticipation of answers

Particularly, large bore +short stroke=low rpm torque
Always seemed backwards to me.

 

The Vortec designation is the term they use at chevy for truck motor. It's not really anything specific to the motor itself. The cylinder head design is based on the gen2 motors which were more of a performance design that had been floating around in the aftermarket for years.

Bore vs Stroke isn't very complicated. Basically the big bore short stroke motor will rev higher and make more high-end power. That's because it can move large amounts of air very quickly since the bore holds alot and the piston doesn't have to travel far to open or close the cylinder. The long stroke small bore motors are better for low rpm torque. They take in and expell air at a slower rate due to the long travel of the piston. The increased stroke allows for a leverage advantage which increases the torque output. Basically a big bore short stroke motor should be decent at high rpm numbers, while a small bore long stroke motor of the exact same displacement will rev lower and produce more torque.

The GM v6 motors pretty much all come from the Buick design. The 350 with a couple cylinders chopped off to make the 3.8, turned into the 3800, then series 2, then series 3.

 

Exactly my understanding but the 455 has a short stroke compared to bore. Which is contrary to your answer.

Or am I missing something here?

 

Actually Buick's very 1st. engine was OHV & continue that way until today. Buick was 1st. in many things. It would take me days to list how many!!!!!!

 

If you look at the head design, Denny Manner was the lead engineer on the 455 development....Buick 455 engines made so much torque at such a low rpm due to the head design......even compared to the Olds 455 and Pontiac 455......and no...Rochester was its own division and Buick had nothing to do with it except to specify what carbs it wanted for the engines.

According to Denny Manner...his influence was strong in getting TurboHydromatic to make the BB TH400 Stage1 trans valve body do what he wanted it to do.....so we have a unique valve body for Stage1 cars....see the article on the site below for all the details......very good article!

 

Buick lead the way in 1903. In the '30s and '40s; the Buick Straight 8s out performed Cadillac V8s and Packards. Buick passenger car engines powered the cross country Flxible Buses from the '20s up until the '50s (up until; they went to diesels).
And, don't forget the automatic transmissions. Buick designed the first automatics back in the thirties. Buick automatics were used in the tanks during WW2. Don't believe the trash talk about the Dynaflow. It is fine durable transmission. The TH350 and TH400 have roots in Buick Engineering Dept.

 

George, also the switch pitch is derivitive of the varible pitch from the Dynaflow.

 

The Buick big block is close to a square engine. The 400 would actually be classified by most as a square engine (bore and stroke basically the same). The 455 is the farthest from square but still not far off. I'm betting on a graph the 455 has a bit more topend and a bit less of a torque curve down low than the 400 does. Probably why people still use the 401 nailheads in trucks.

 

Are the intake runners in the 455 heads longer than most big blocks of that era? I always thought that a longer intake runner (such as a high rise intake or carb spacer) increases torque. Also, the 455 intake is a little wider than say the Chevy 454, which makes for a longer runner too. I think that's why the LS motors have those long runners (cross style) on their intakes - to increase velocity for better torque.

And then, yes, the "short stroke" of the 455 allows it to rev well. Sort of weird, since the Buick 350 was the only small block of the era with a longer stroke than bore, but it has plenty of torque too. Don't get me started on the Buick 350 - I'm soooooo waiting for aluminum heads.

Also, I think the 4.3 is what you get when you chop two cylinders off of the Chevy 350. And I thought the 3800 V6 was based off of (if not another generation of) the 231/3.8 that made the GNs so popular. AND, Buick had the first aluminum V6, right? What about sequential fuel injection - Buick's idea?

And don't forget the awesome cross-fire intake with air gap on the nailheads. Too cool!

I think Buick had a say in leaving the ventura rings in the quadrajet on the 800cfm after Pontiac had them removed on their 800's to try and increase cfm. But the rings proved better for throttle response while not really hurting cfm at WOT.

As for the automatics, I should have remembered to mention the switch pitch. The Dynaflow as a great transmission; not very efficient, but super smooth and reliable.

Anyway, I was hoping to find more info on the similarities between the LS design and Buick's V6(s). Anyone?

 

Nope

 

Louis Chevrolet's brother is the one who patented the OHV design.

 

The only real similarity I can think of offhand between the Buick v6 and the LS series motors is the fact that they are both deep skirt block designs.

The LS motors take this a step further, however as the mains are cross bolted for even more strength.

 

That is true, but David Dunbar Buick invented it. Buick was not much of a businessman. Gaston Chevrolet was.

 

It has been written that Buick was heavily involved in the development of the drive train for the Toronado / Eldorado.
GM intended for the '66 Riviera to be front wheel drive also, but Buick didn't feel the drive train was 100% yet. So the Riviera remained rear wheel drive.

 

the first buick v6 was a 300 v8 minus 2 cylinders. same stroke and same deck height and a very close bore size. same exhaust port arrangement except it is missing one port. they did enlarge the rod journals on the later 3.8 v6 and ended up with the 231

 

Are we saying what was good enough for Cadillac and Olds wasn't for Buick ?
or cadillac Olds got the Buick rejects.

 

I've wondered the same thing myself. :laugh:
Wish I could remember off hand where I read this. I would quote my sources.

 

The irony in this was that the Eldorado/Toronado drivetrain actually worked very well. I'm glad the Riviera stayed RWD though.