I'm lusting after a different V12...

"cletus44 aka Clayton Seams" (cletus44) 08/18/2016 at 14:38 • Filed to: None

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While GenuineAlexReid is !!!error: Indecipherable SUB-paragraph formatting!!! , I’m lusting after one of these. It’s the monster 11.5L GMC V12 made from 1962-1965. Lemme lay some specs on you:

It weighs 1,485 pounds sans transmission
It has 4 heads
The crank weighs 180 pounds
It makes 250 hp at 2,400 rpm and 630 lb. ft. at 1,600 rpm

Here’s the rub. There are about 2-300 of these engines left in the world. A ratty non-running GMC V12 will cost $8k. BUT there is one lunatic operation that will sell you a newly restored 702 for $10k. A lot of money, but that’s a lot of engine. I’m far from being able to justify spending $10 grand on an engine but if I ever did, it would be one of these.

E90M3 > cletus44 aka Clayton Seams 08/18/2016 at 14:42

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Needs more power, CAT 3512B for well services, 2250 bhp at ~1900 RPM with 6300 ft/lbs of torque from 1400-1900 RPM.

RamblinRover Luxury-Yacht > cletus44 aka Clayton Seams 08/18/2016 at 14:44

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The line of V6s that they made the Twin Six related with actually goes up some in bore size *and* stroke from what it had. If you had a block and a custom crank and fresh parts for a large bore V6, you could go WAY bigger. Over a thousand CI - I know this for a fact because I’ve calculated it.

jimz > cletus44 aka Clayton Seams 08/18/2016 at 14:46

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how would sir like a 2-stroke V12?

Takuro Spirit > cletus44 aka Clayton Seams 08/18/2016 at 14:46

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I saw one, fittingly inside a GMC truck driving around last year when they kicked off Power Tour in Madison.

I had no idea what it was or that it was a factory thing.

StoneCold > cletus44 aka Clayton Seams 08/18/2016 at 14:46

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Then you’ll need a transmission to handle that torque, then a drive shaft, then axles, when all of a sudden FUNNY CAR

RallyWrench > RamblinRover Luxury-Yacht 08/18/2016 at 14:51

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Of course you did.

cletus44 aka Clayton Seams > jimz 08/18/2016 at 14:53

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I knew those existed but I think they weigh like 2,500 pounds or something. Too bad because they sound AMAZING

Party-vi > cletus44 aka Clayton Seams 08/18/2016 at 14:53

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I’m surprised they’re worth that much. I thought a lot of these were powering oil derricks out west.

cletus44 aka Clayton Seams > Party-vi 08/18/2016 at 14:54

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If that’s true, I might have to take a look. All I know is that the ones on eBay are very pricey.

RamblinRover Luxury-Yacht > RallyWrench 08/18/2016 at 14:55

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Party-vi > cletus44 aka Clayton Seams 08/18/2016 at 14:55

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Just get two old 351 V6 engines and bolt them back to front. Bam. Instant 702 without the 100lb crankshaft.

shop-teacher > cletus44 aka Clayton Seams 08/18/2016 at 14:59

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I am suddenly overcome with the urge to put one of these in the bed of a square body Chevy. How useless! How perfect!

Jcarr > cletus44 aka Clayton Seams 08/18/2016 at 15:00

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Yes. Yes they do.

camaroboy68ss > cletus44 aka Clayton Seams 08/18/2016 at 15:20

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Passed up two of them at the Portland swap meet a couple years ago. Both complete motors, really the only unique thing is the short block everything else was just off the shelf stuff

GenuineAlexReid - The Reidus > cletus44 aka Clayton Seams 08/18/2016 at 15:23

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We need to double-V12 the Vette.

cletus44 aka Clayton Seams > GenuineAlexReid - The Reidus 08/18/2016 at 15:24

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alek pls

GenuineAlexReid - The Reidus > cletus44 aka Clayton Seams 08/18/2016 at 15:25

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WE’LL DO IT LIVE

jimz > GenuineAlexReid - The Reidus 08/18/2016 at 15:28

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how would you like a two stroke V24?

cletus44 aka Clayton Seams > jimz 08/18/2016 at 15:31

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It’s not every day that stuff on the internet surprises me but I had no idea this ever existed. I’m gobsmacked. What would this have been used in? Submarines? Trains? Powerplants?

jimz > cletus44 aka Clayton Seams 08/18/2016 at 15:41

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stationary roles, like pumps, generators, etc. and marine propulsion. The -71 series Detroit Diesels were truly “modular” engines. They were made in 1, 2, 3, 4, 6, V6, V8, V12, V16, and V24 configurations. They all shared common piston/liner/rod assemblies. Each config had to have its own block and crankshaft, but from then on it was mix and match parts. building a 4-71? take a 4-71 block and crank, stuff in four -71 pistons and liners, and plop a 4-71 head on it. want an 8V-71? Take an 8V-71 block and crank, stuff in eight -71 series pistons/liners, put two 4-71 heads on it. and so on.

bhtooefr > cletus44 aka Clayton Seams 08/18/2016 at 15:52

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I’ve actually wondered how long it’ll be before engines like this come back.

Cummins has, with Westport, done the ISL G (an 8.9 liter turbocharged straight 6) and the ISX12 G (an 11.9 liter turbocharged straight 6) as spark ignition engines for natural gas applications. They’re got throttle response issues, though, especially considering that they basically use single point “injection” of the natural gas at the throttle body. And, natural gas doesn’t work so hot for long haul workloads. (Granted, I think long haul trucking is stupid, and rail is better, but hey )

Especially with modern valve actuation strategies, I wonder how long it’ll be before someone decides that the emissions issues with the modern 11-15 liter turbodiesels warrants making a big (maybe 15-20 liter, to avoid turbocharging) gasoline engine, with port injection (to avoid the particulate emissions issues that DI has, and reduce cost), and Atkinsonization. (Alternately, make the engine smaller - the 702 being a good size - and hybridize to help it climb.)

Die-Trying > cletus44 aka Clayton Seams 08/18/2016 at 18:03

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say, just build your own......... all that it actually is, IS two gmc 305 v6 engines that are coupled nose to tail..........(chain coupler)

(something similar to this)

THE rub with your v12, is that the pistons weigh a TON............ its not an rpm engine...... its an industrial torque monster....... you would have to get a custom ordered set of lightweight pistons, in order to get the thing to stay together at any REAL rpm............otherwise the you’ll pull the rods in two.......

305 v6 are more common anyhow......

BayAreaMiataBoi > cletus44 aka Clayton Seams 08/18/2016 at 20:20

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What about the 1,100 cubic inch (18 liter) Ford tank GAA motor, with 1,350 lbs-ft of torque between 2000-3000 rpm?
See: http://www.fordgaaengine.com